hopefully easy electronics question
Stephen Jacobs
and a stamped label on the RF shield is dated 1983.
The system does not power up.
Surrounding many of the solder points on the underside of the
motherboard is some kind of residue that looks like some sort of brown
syrup-ish substance, a bit like old Coca-cola. Might be nothing.
The previous owner indicated that he received the system with the
incorrect power supply. He obtained the correct power supply, and never
got the machine to work.
I noticed 3 components, labelled C30, C32, & C33. These components look
like discs, mostly olive green, with shiny black coloring at the tops.
A) I'm guessing these are capacitors - am I right?
B) Are these components supposed to be all green, and is the black on
the top indicative that they've fried?
C) Is it reasonable to conclude that the wrong power supply was hooked
up, and it fried these capacitors? If so, could I probably get the
system working by replacing these capacitors?
Thanks for any help,
Steve
Heath Young
>motherboard is some kind of residue that looks like some sort of brown
>syrup-ish substance, a bit like old Coca-cola. Might be nothing.
This is flux - it is nothing, although it may indicated that these
components have been replaced if all of the joints don't have this.
>The previous owner indicated that he received the system with the
>incorrect power supply. He obtained the correct power supply, and never
>got the machine to work.
Then the owner previous to the previous owner may have blown the $hit out of
the board with the incorrect power supply - hope you didn't pay too much for
it!
>A) I'm guessing these are capacitors - am I right?
Yes. Sounds like disc cermics
>B) Are these components supposed to be all green, and is the black on
>the top indicative that they've fried?
No, it probably indicates that when the board was made, these components
were marked with black paint to show that they are in the correct place.
>C) Is it reasonable to conclude that the wrong power supply was hooked
>up, and it fried these capacitors? If so, could I probably get the
>system working by replacing these capacitors?
No. And No. There may be other issues, if someone has connected up a power
supply that has a higher voltage than what is supposed to be, they they may
have done irrepairable damage to the board - like I said, I hope you didn't
pay too much for it.
First I would check that all of the chips are installed correctly, but this
is about the most that you can do yourself. I would suggest taking it to a
repair place and getting them to have a look at it, but I don't fancy your
chances, as it is an antique, and a lot of the integrated circuits will now
probably be obsolete.
There may be newsgroups who specialise in Atari gear - or at least
websites...
Cheers
Heath Young
Stephen Jacobs
says...
The Atari 5200 came in 2 flavors - one with 2 controller ports, and one
with 4 controller ports. As a kid I was given a 2-port model, and loved
it, but I always wanted a 4-port. The 4-port used an automatic RF
switchbox that the 2-port could not use. Additionally, there are 2 or 3
games that don't work on the 2-port models.
For this trade, no money changed hands. As I had 2 functioning 2-ports,
and the previous owner agreed to pay shipping both ways, I made the
trade hoping to get something fixable. If not, it's no big loss.
I've also posted to a couple of Atari web-forums, but the Atari
newsgroups seem to have plummeted in quality over the last 2-3 years, so
in all honesty, I didn't even think to post to any of them. It's a good
idea though; I'll give it a try.
As for the chips, there is no visible damage to them, for what little
that's worth. And they seem solidly seated in their sockets, but I
suppose I could always reseat them just in case that's the problem.
Thanks for the help,
Steve
Stephen Jacobs
> >incorrect power supply. He obtained the correct power supply, and never
> >got the machine to work.
>
> Then the owner previous to the previous owner may have blown the $hit out of
> the board with the incorrect power supply
>
> >up, and it fried these capacitors? If so, could I probably get the
> >system working by replacing these capacitors?
>
> No. And No. There may be other issues, if someone has connected up a power
> supply that has a higher voltage than what is supposed to be, they they may
> have done irrepairable damage to the board - like I said, I hope you didn't
> pay too much for it.
>
Per your suggestion, I took this over to the rec.games.video.atari
newsgroup. Somebody there suggested I check the voltage regulator, and
indicated it is supposed to output a steady +5v DC. I found 2 voltage
regulators (I'm confident they were voltage regulators - they were where
he described, and the markings on the board next to them were VR1 &
VR2). Each was attached to a large heatsink with a screw through a metal
plate at the top of the regulator. These are 7805 regulators, supposedly
a standard off-the-shelf part.
To test them, I touched the negative probe of my multimeter to the
aluminum shielding around the system board, and the postive probe to the
rightmost leg of the component. I saw a value of .74v on each regulator.
I then retested, this time touching the negative probe to the screw
through the top of the regulator. I got the same result.
Did I test these properly? If so, is it plausible that the regulators
blew, and this is the result? Assuming I don't mind the possible waste
of time and effort, are 7805 regulators inexpensive enough that I might
try replacing them to get the system running again?
Thanks,
Steve
John Musielewicz
You also need to check the voltage going in to the regulators. It
sounds like the bridge might be blown too. Tough the probe to the leg
on the other side and see if you have voltage.
Jeroni Paul
It's great to see someone trying to repair an old Atari.
To answer your questions:
The 7805 is a voltage regulator with 3 legs:
left: unregulated voltage input (should be minimum 6.5V)
middle: ground (and should be the same as the metal screw)
right: voltage output regulated (5V)
So, to test them attach negative probe to middle leg (or screw) and
test voltage on both legs; left should have at least 6.5V and right
5V.
If the left leg has correct voltage then the regulator is faulty. It
is not expensive and you should find it in any shop selling electronic
components. It's a very standard part. If they are faulty you should
indeed replace them since the Atari has more value than the cost of
these regulators.
If the left leg has a voltage under 6.5V, trace the connection (the
regulator may not be faulty). For that you'll have to unscrew the
board to access its solder side, follow the track on the board and
check where it goes - it should go to the power plug, although there
could be some resistor or fusible in the path that might have open.
Good luck,
Jeroni Paul
Stephen Jacobs <St...@JacobsHome.org> wrote in
news:<MPG.17c79e8c6...@news.speakeasy.org>
Stephen Jacobs
JERON...@terra.es says...
> Hi Stephen
>
> It's great to see someone trying to repair an old Atari.
>
> To answer your questions:
> The 7805 is a voltage regulator with 3 legs:
> left: unregulated voltage input (should be minimum 6.5V)
> middle: ground (and should be the same as the metal screw)
> right: voltage output regulated (5V)
>
> So, to test them attach negative probe to middle leg (or screw) and
> test voltage on both legs; left should have at least 6.5V and right
> 5V.
>
> If the left leg has correct voltage then the regulator is faulty. It
> is not expensive and you should find it in any shop selling electronic
> components. It's a very standard part. If they are faulty you should
> indeed replace them since the Atari has more value than the cost of
> these regulators.
>
> If the left leg has a voltage under 6.5V, trace the connection (the
> regulator may not be faulty). For that you'll have to unscrew the
> board to access its solder side, follow the track on the board and
> check where it goes - it should go to the power plug, although there
> could be some resistor or fusible in the path that might have open.
>
> Good luck,
> Jeroni Paul
>
>
BUT, there is no power jack. This unit gets it's power via the RF cable,
from the Game-switchbox. IE, the AC Adapter plugs into the switchbox,
and the switchbox sends the voltage down the RF wire to the game system.
Thanks for the advice. I'll investigate further and report back my
results.
Steve
Stephen Jacobs
>
> It's great to see someone trying to repair an old Atari.
>
> To answer your questions:
> The 7805 is a voltage regulator with 3 legs:
> left: unregulated voltage input (should be minimum 6.5V)
> middle: ground (and should be the same as the metal screw)
> right: voltage output regulated (5V)
>
> So, to test them attach negative probe to middle leg (or screw) and
> test voltage on both legs; left should have at least 6.5V and right
> 5V.
>
> If the left leg has correct voltage then the regulator is faulty. It
> is not expensive and you should find it in any shop selling electronic
> components. It's a very standard part. If they are faulty you should
> indeed replace them since the Atari has more value than the cost of
> these regulators.
>
> If the left leg has a voltage under 6.5V, trace the connection (the
> regulator may not be faulty). For that you'll have to unscrew the
> board to access its solder side, follow the track on the board and
> check where it goes - it should go to the power plug, although there
> could be some resistor or fusible in the path that might have open.
>
> Good luck,
> Jeroni Paul
I've tested the left leg (unregulated voltage) both voltage regulators -
one reads 4.2v, the other 4.0. What should I try next?
Thanks,
Steve
Shaun Davy
fine. it is usually very hard to blow up a 7805, they are internally
protected and limited. if the meter you were testing was set to DC not AC
then it now appears that something between your AC input and the regulator
is dead. there should be basically a bridge rectifier labeled something like
BR1 (or possably 4 diodes marked D1, D2 etc) and a few caps on the input of
the regulator. ASSUMING THERE IS A LOW INPUT VOLTAGE (no transformer or 240V
input!!!!) with the unit powered set your meter to AC and measure the AC
input. it wants to be alteast 6V and should be in the ball park of what is
written on the AC plug pack. if that is fine switch your meter back to DC
and put it on the bridge rectifer pins marked + (red lead) and - (black
lead). the reading here should be a bit higher than the AC input measured eg
for a 6V in be about 8V or so. if not then the bridge looks dead. after this
the + leg on the bridge should end up on the left pin on the 7805(possible
not directly). if the voltage on the bridge is good than something in
between the bridge and 7805 is dead. caps etc. if not the bridge could be
dead or something pulling it down. can do further testing if this is the
case.
let us know when u have tested a bit more or need more help understanding
what ive just written and will be happy to help. (either via newsgroup or
email)
Good luck,
Shaun
"Stephen Jacobs" <St...@JacobsHome.org> wrote in message
news:MPG.17ca20ceb...@news.speakeasy.org...
Stephen Jacobs
shau...@bigpond.com says...
> Am not familiar with the atari but it appears that the voltage regulator is
> fine. it is usually very hard to blow up a 7805, they are internally
> protected and limited. if the meter you were testing was set to DC not AC
> then it now appears that something between your AC input and the regulator
> is dead. there should be basically a bridge rectifier labeled something like
> BR1 (or possably 4 diodes marked D1, D2 etc) and a few caps on the input of
> the regulator. ASSUMING THERE IS A LOW INPUT VOLTAGE (no transformer or 240V
> input!!!!) with the unit powered set your meter to AC and measure the AC
> input. it wants to be alteast 6V and should be in the ball park of what is
> written on the AC plug pack. if that is fine switch your meter back to DC
> and put it on the bridge rectifer pins marked + (red lead) and - (black
> lead). the reading here should be a bit higher than the AC input measured eg
> for a 6V in be about 8V or so. if not then the bridge looks dead. after this
> the + leg on the bridge should end up on the left pin on the 7805(possible
> not directly). if the voltage on the bridge is good than something in
> between the bridge and 7805 is dead. caps etc. if not the bridge could be
> dead or something pulling it down. can do further testing if this is the
> case.
> let us know when u have tested a bit more or need more help understanding
> what ive just written and will be happy to help. (either via newsgroup or
> email)
> Good luck,
> Shaun
Wow, thanks for the help. You guys are giving me far more useful
information than I was expecting. I'm getting excited to think it might
be possible to resurrect this thing. At the very least, I'm learning
more about electronics, which by itself is a small thrill for me.
Anyway, to the topic at hand...
I don't know what a bridge rectifier looks like. I found a couple of
dissimilar images using Google Images; one looked like a small cylinder,
which to my eye could just as easily been a resistor, capacitor, or any
other small cylindrical electronic component. The other looked like a
black square with 4 legs.
Using Google Images for diodes, it looks to me like a diode is another
small black cylinder, this one with a stripe at one end to indicate
polarity.
Examining the board, I found no markings with 'BR' or 'D' at all,
anywhere. There is only one section I can't examine, and I don't think
power-related circuitry is located there. But, in case I'm wrong, this
area is small, maybe 1.5-2 inches by 1 inch. It has a metal shield
covering it up, and I can't figure out how to remove the metal shield.
(Obviously I don't want to break anything further.) On one side is a
small hole, no wider than a cigarette, and there is a red plastic tubeon
the inside of the hole - it looks like the type of socket that
technicians can insert a screwdriver-like tool into to adjust things. It
reminds me of the tuner component inside analog-tuner radios, that often
have a tiny hole, I believe for precise adjustments. Sticking out of one
side of this shielded area is a small board with 3 ceramic disc
(resistors?) components attached. As I said, I don't think this is where
the components I'm looking for are, but I don't want to leave out
anything that might be useful.
This system has an unusual power supply system. It uses an AC Adapter
that puts out 13v DC to an automatic switchbox. The switchbox connects
to the antenna inputs on the TV, and an RF signal cable connects the
videogame console to the switchbox. The 13v DC voltage travels along the
RF signal cable to the console. If I test the voltage at the end of the
RF cable where it is soldered to the motherboard the voltage is still at
13v, so the problem isn't a bad cable. Obviously I need to find where
the voltage goes away (sounds like a Larry Niven story).
Would it help if I took close-up pictures of the board and it's
components, and posted them to a webpage? I could do that without too
much trouble, and maybe you could then get a better image than from my
weak descriptions.
Thanks,
Steve
Jeroni Paul
> This system has an unusual power supply system. It uses an AC Adapter
> that puts out 13v DC to an automatic switchbox. The switchbox connects
> to the antenna inputs on the TV, and an RF signal cable connects the
> videogame console to the switchbox. The 13v DC voltage travels along the
> RF signal cable to the console. If I test the voltage at the end of the
> RF cable where it is soldered to the motherboard the voltage is still at
> 13v, so the problem isn't a bad cable. Obviously I need to find where
> the voltage goes away (sounds like a Larry Niven story).
Since the wall adapter is putting out DC voltage, there is NO
rectifier bridge to look at, so forget about it.
Good, you found where the 13V arrive at the board. Now you've to
follow the copper track on the board to see where these 13V go and
where they are lost. I belive you'll probably find a burned or open
fuseable resistor or fusible. (A resistor looks like a small cylinder
but has colours painted on it).
Attach the negative probe to the negative of these 13V and use the
positive probe to test voltages following the copper track on the
board. Follow resistors or diodes. You can check resistors and diodes
with your multimeter, using this page to obtain the resistor values:
http://www.csgnetwork.com/resistcolcalc.html
You should use your DC meter to measure the voltages after the
components you find when you follow the copper track on the board. So,
you can see where these 13V drop down to lower than 6.5V. Keep in mind
this may not be the culprit, so repost with this information.
> Using Google Images for diodes, it looks to me like a diode is another
> small black cylinder, this one with a stripe at one end to indicate
> polarity.
Yep, looks like this is a diode.
Good luck,
Jeroni Paul
Stephen Jacobs <St...@JacobsHome.org> wrote in message news:<MPG.17ca42792...@news.speakeasy.org>
>
Stephen Jacobs
I've added a quick, dirty annotated photo of part of the system board
I'm discussing to my website. Admittedly, the website is lousy, so don't
bash it, please. It's not a high priority.
More relevant, I have posted a picture of the corner of the system board
that I believe contains the power input circuitry and components. I have
labelled a few of the components, as best I can.
If any other pictures would be helpful, let me know and I'll see what I
can do.
To look at the page in question, go to http://64.81.193.244, and click
the link on the left labelled 'Videogames'.
Thanks,
Steve
Shaun Davy
on the board seen u have a DC input. Have looked for a schematic for the
atari 5200 but cannot find 1 so what your going to have to do is probaly
remove board so u can see the underneath side and then follow where in 13V
DC input goes by following the copper tracks.it may split off in 2 or more.
1 will probaly go into the silver box (forget it not power section) but it
will end up on the left (input leg) of the 7805. write down what components
are between them (can use R3, C45 etc if u want!) it may take a bit to suss
things out but will be well worth it. also see if u can see components
running from the input to ground(which will be connected to the outer of the
coax). also there are points where the track runs from top to bottom layer
on the board and vice versa. they will be shown by a dot matching up on the
top and bottom of board. when u find out the path to the 7805 u can go ahead
and stick the black lead on ground and step it through your components and
see if u can see where u loose the voltage. before u check any of these
suggestions check that u have 13V DC or what ever it is supposed to be at
the input of the atari when plugged in and on.
OK i know i have waffled on a fair bit too much again but try it, and be
patient with tracing circuit. also the "what is this" section is a capacitor
also.
PS check the compoent on the lower side of the L13 marking i think is on on
the pic. looks a bit black!
"Stephen Jacobs" <St...@JacobsHome.org> wrote in message
news:MPG.17cb8eeeb...@news.speakeasy.org...
Ralph Wade Phillips
"Stephen Jacobs" <St...@JacobsHome.org> wrote in message
news:MPG.17cb8eeeb...@news.speakeasy.org...
I'd first pull the two 7805's and see what voltage I got on the
input. If it's back to 13V, then I've got a bad 7805 pulling it down (or a
bad cable, causing excessive voltage drop!)
If it's still at 4V, then I'd check that electrolytic capacitor (the
one labeled "What's that?") by pulling IT.
Past that, check out the schematics available from Bomarc
(www.bomarc.org) which will make it somewhat easier to trace out what's
happening where.
RwP
Stephen Jacobs
copy was sent to the cited author.]
In article <ajtjdf$1dsp1n$1...@ID-81734.news.dfncis.de>,
ral...@techie.com says...
> Howdy!
>
> I'd first pull the two 7805's and see what voltage I got on the
> input. If it's back to 13V, then I've got a bad 7805 pulling it down (or a
> bad cable, causing excessive voltage drop!)
>
> If it's still at 4V, then I'd check that electrolytic capacitor (the
> one labeled "What's that?") by pulling IT.
>
By pulling, do you mean I should physically remove them
from the board? I have little faith in my soldering skills,
and am hoping to minimize any soldering work I need to do.
Of course, it's possible I might just have inadequate
tools. The only soldering equipment I have (or have ever
used) is a large-tipped soldering gun from Radio Shack.
> Past that, check out the schematics available from Bomarc
> (www.bomarc.org) which will make it somewhat easier to trace out what's
> happening where.
>
> RwP
I have found schematics at
http://www.atariage.com/5200/archives/schematics/ . I
believe the section I'm interested in is contained in the
'switchbox' schematic. I think that drawing includes the
power-related circuitry in the console itself, as well as
the circuitry in the actual physical switchbox that
attaches to the TV.
-Steve
Jeroni Paul
Indeed as Shaun Davy mentioned the component on top left of the
picture, just under the L13 inductor looks like a burned resistor!
I can't see where the copper trace goes because there's that green
capacitor in front, but maybe the copper trace from the left leg of
the regulator goes to the leg of that resistor?
To test, put negative probe of your DC voltage meter to negative of
13V supply, then with positive probe measure voltage on both legs of
that burned resistor - you might measure 13V on one leg and 4.5V on
the other - if this is the case you know where the 13V are dropping.
Then that resistor will need to be replaced.
Take a look at the board to see if there are more components looking
burned like this one.
Good luck,
Jeroni Paul
Stephen Jacobs <St...@JacobsHome.org> wrote in message news:<MPG.17cb8eeeb...@news.speakeasy.org>
Ralph Wade Phillips
"Stephen Jacobs" <St...@JacobsHome.org> wrote in message
news:MPG.17cc34a47...@news-remote.speakeasy.net...
> [This followup was posted to sci.electronics.repair and a
> copy was sent to the cited author.]
>
> In article <ajtjdf$1dsp1n$1...@ID-81734.news.dfncis.de>,
> ral...@techie.com says...
> > Howdy!
> >
> > I'd first pull the two 7805's and see what voltage I got on the
> > input. If it's back to 13V, then I've got a bad 7805 pulling it down
(or a
> > bad cable, causing excessive voltage drop!)
> >
> > If it's still at 4V, then I'd check that electrolytic capacitor
(the
> > one labeled "What's that?") by pulling IT.
> >
>
> By pulling, do you mean I should physically remove them
> from the board? I have little faith in my soldering skills,
> and am hoping to minimize any soldering work I need to do.
> Of course, it's possible I might just have inadequate
> tools. The only soldering equipment I have (or have ever
> used) is a large-tipped soldering gun from Radio Shack.
>
Yes, that's what I mean. And, if you're not feeling comfortable
with your soldering skills, I'd not recommend you learn how on this project
(grins!)
Pick up a few small project kits and practice on them first.
Yes, you DO need better tools, but that big gun might be needed for
power components, so I wouldn't ditch it.
> > Past that, check out the schematics available from Bomarc
> > (www.bomarc.org) which will make it somewhat easier to trace out what's
> > happening where.
> >
> > RwP
>
> I have found schematics at
> http://www.atariage.com/5200/archives/schematics/ . I
> believe the section I'm interested in is contained in the
> 'switchbox' schematic. I think that drawing includes the
> power-related circuitry in the console itself, as well as
> the circuitry in the actual physical switchbox that
> attaches to the TV.
Ah. Yep, that helps some.
I'd also check the two MJE-210's to see what it looks like around
them, since they appear to be switches to turn the DC on to the regulators.
BTW - The "LM340T5" is an exact replacement for the 7805, so they're
the same (just different numbers from different manufacturers.)
RwP
Ralph Wade Phillips
"Stephen Jacobs" <St...@JacobsHome.org> wrote in message
news:MPG.17cc34a47...@news-remote.speakeasy.net...
> [This followup was posted to sci.electronics.repair and a
> copy was sent to the cited author.]
In addition to the other posts, for information, Cxx parts are
typically capacitors, Lxx parts are inductors, Rxx parts are resistors, and
ICxx or Qxx are ICs or semiconductors.
The big green thing is the .22uF capacitor shown on the input of
both regulators. It would have been nice if the schematic author had
annotated them with the reference IDs on the board, but still ... <grins>
RwP
Stephen Jacobs
copy was sent to the cited author.]
In article <6c768c09.0208200833.69487330
@posting.google.com>, JERON...@terra.es says...
> Hi,
>
> Indeed as Shaun Davy mentioned the component on top left of the
> picture, just under the L13 inductor looks like a burned resistor!
> I can't see where the copper trace goes because there's that green
> capacitor in front, but maybe the copper trace from the left leg of
> the regulator goes to the leg of that resistor?
> To test, put negative probe of your DC voltage meter to negative of
> 13V supply, then with positive probe measure voltage on both legs of
> that burned resistor - you might measure 13V on one leg and 4.5V on
> the other - if this is the case you know where the 13V are dropping.
> Then that resistor will need to be replaced.
>
> Take a look at the board to see if there are more components looking
> burned like this one.
>
I think it just looks that way in the picture - otherwise I
can't believe I wouldn't have spotted that upon visual
examination. I'll check it when I get home.
There are several components, the same size and shape as
resistors, but made of what looks like glass, and have
writing/numbering printed on them. I think that is what
that component you are talking about is.
As I said, I'll look at it again tonight and post back.
Thx again for all the help you guys are giving. I can't
wait to get this system running again, and assuming I do
you all will deserve a lot of the credit.
-Steve
Jeroni Paul
leg that does NOT mean the regulator is bad or shorted.
Imagine there's a high value resistance in series, pulling the regulator
will get you full 13V there, that due to the current draw being zero.
Looking at the schematic there aren't many places to look at: check the
MJE-210 transistors and these two resistors that are connected in it. You
can do that with the ohms and diode test of your multimeter. Check for
shorts (any reading of 0 ohm on any pins of the transistor is indication of
a bad transistor).
Chances are there is a collector to base short and the 182 ohm resistor is
burned - you should check for 0 or few ohms of continuity bewteen the legs
of the transistor before replacing the resistor. Could also be the
transistor is ok and the resistor is burned. And the regulators could also
be bad.
As an aid the schematic includes voltage readings on different points of the
circuit. Use them as a reference and check voltages on the legs of the
components. The faulty part resides where they start not matching.
And you should know, if you remove a regulator you can test it easily: use
the available 13V, contact negative to middle leg and positive to left leg.
Then measure voltage between middle leg and right leg: should be 5V. If you
measure less voltage it's bad (keeping in mind the 7805 can output from 4.5V
to 5.5V). If you measure 13V in the output, it could be bad or not, that
depends: some ST regulators didn't regulate without a load, it could be one
of these. Anyway, if you measure 13V, the regulator is not the cause for the
Atari not to work.
Good luck,
Jeroni Paul
"Ralph Wade Phillips" <ral...@techie.com> wrote in
news:ajts6n$1dfgrf$1...@ID-81734.news.dfncis.de
Jeroni Paul
if the input is shortcircuited; that is if there is little resistance
between the left and middle leg (for example less than 100 ohm), in this
case the regulator is faulty and don't test it or you would shortcircuit the
13V supply!
Jeroni Paul
"Jeroni Paul" <JERON...@terra.es> wrote in
news:aju69d$7f4$1...@nsnmpen2-gest.nuria.telefonica-data.net
Jeroni Paul
> [This followup was posted to sci.electronics.repair and a
> copy was sent to the cited author.]
>
> can't believe I wouldn't have spotted that upon visual
> examination. I'll check it when I get home.
Assuming it's not a resistor and is not burned: you'll have to match the
schematic you found with your machine. This is the best way to properly
troubleshoot something. See how the lines drawn in the schematic match with
the copper (green) traces on the board. So, you can identify the components
we've spoken in a previous thread even if the labelings do not match. You
should be able this way to find the transistor we mentioned you should
check, and check it, and also the resistors you should check, this all
starting from the RF plug and following the green copper traces on the
board. When you're not sure if you followed a trace correctly, use your
ohmeter - two points are connected if they show 0 ohm between them.
Once transistors MJE-210 and two resistors are checked, if they check fine
you'll have to suspect the voltage regulators - remove them and test them as
I explained in a previous post. A failure of one of the regulators will pull
down its supply and cause nothing at all to work, so you'll have to remove
and test them separately.
Lastly, when you replace a part keep an eye at its temperature the first
time you power the system, just in case there's still some fault that would
otherwise burn the component again. If it gets hot quickly disconnect the
power immediately and search for more defective parts.
> There are several components, the same size and shape as
> resistors, but made of what looks like glass, and have
> writing/numbering printed on them. I think that is what
> that component you are talking about is.
Looks like a diode. There are many kinds of diodes, ones being black and
others being transparent, or others having other colours. They all should
have a bar at one end to mark the polarity.
> As I said, I'll look at it again tonight and post back.
>
> Thx again for all the help you guys are giving. I can't
> wait to get this system running again, and assuming I do
> you all will deserve a lot of the credit.
You are welcome.
> -Steve
Jeroni Paul
Stephen Jacobs
--------------------------------
I ask some very ignorant, untrained questions here. Please bear with
me....
--------------------------------
I've added more pics to the webpage: http//64.81.193.244 , hit the
'videogames' link on the left.
The burned-out resistor-looking component near L13 is actually labelled
C127. It looks like a small glass cylinder with bronze-colored ends, and
has 50v printed on the side. I don't know what it is, but it doesn't >
look< burned out.
*IF* I followed the traces on the board accurately, it looks to me like
the MJE-210s mentioned on the schematic are components that look to me
like the voltage regulators, and have 7805a stamped on them. The contact
points on the board are labelled E, C, & B - Emitter, collector, base?
If these are indeed the MJE210s, I tried to read them. They both gave
the same results:
I had my multimeter set to Ohms, 2k. Next to the 2k was a small picture
that looked like an arrow merged with a + sign -- is this symbol
supposed to represent a diode? An image of the multimeter, set the way
it was set when I took these readings, is on the webpage. The image also
shows where I had the probes plugged in. The black probe was plugged in
to the socket labelled 10A, and the red probe was plugged in to the
socket labelled A(ohm symbol). I took these readings with the power NOT
connected to the system.
With the red probe touching the B contact, and the black probe touching
the C contact, I read a value of about 1.6-1.7.
Touching Red to C, and black to B, I read a value of .6-.7.
One thing that definitely doesn't make sense to me about the multimeter:
In the Ohms section of the dial, there is a '200' position, and a '2k'
position. As I understand things, this simply adjusts the scale of the
display, and where the decimal appears. You simply set the knob to
something that will be in the range of what you are testing. BUT, when I
tested the components above in the 200 setting, there was no reading,
yet in 2k (2000) I saw values much smaller than 200, smaller than 2 for
that matter. The only thing I see that might explain this is the symbol
next to the 2k is only next to the 2k, none of the other settings. I
assume this symbol means something relevant to this.
Thanks again,
Steve
Ralph Wade Phillips
"Stephen Jacobs" <St...@JacobsHome.org> wrote in message
news:MPG.17ccbe8be...@news.speakeasy.org...
> OK, moving along....
>
> --------------------------------
> I ask some very ignorant, untrained questions here. Please bear with
> me....
> --------------------------------
>
>
> I've added more pics to the webpage: http//64.81.193.244 , hit the
> 'videogames' link on the left.
>
> The burned-out resistor-looking component near L13 is actually labelled
> C127. It looks like a small glass cylinder with bronze-colored ends, and
> has 50v printed on the side. I don't know what it is, but it doesn't >
> look< burned out.
It isn't. It's a small silicon diode with a glass case. Used to be
VERY common, but most today are epoxy.
>
> *IF* I followed the traces on the board accurately, it looks to me like
> the MJE-210s mentioned on the schematic are components that look to me
> like the voltage regulators, and have 7805a stamped on them. The contact
> points on the board are labelled E, C, & B - Emitter, collector, base?
> If these are indeed the MJE210s, I tried to read them. They both gave
> the same results:
No, unless 7805 is also the date code. The schematic ALSO shows
some LM340T5, which were identical in form, fit, and circuit function to the
7805. If they are MJE210's produced in the second week of 78, then they'll
ALSO have at least the MJE210 on them.
A MJE210 is probably what's right above the coax in the picture on
your web site - the specs I have say it's in a TO220 case, just like a
LM340T would be.
>
> I had my multimeter set to Ohms, 2k. Next to the 2k was a small picture
> that looked like an arrow merged with a + sign -- is this symbol
> supposed to represent a diode? An image of the multimeter, set the way
> it was set when I took these readings, is on the webpage. The image also
> shows where I had the probes plugged in. The black probe was plugged in
> to the socket labelled 10A, and the red probe was plugged in to the
> socket labelled A(ohm symbol). I took these readings with the power NOT
> connected to the system.
Yes, the arrow merged with the "+" symbol is for diode tests. One
way should show a voltage drop, the other should show open circuit.
>
> With the red probe touching the B contact, and the black probe touching
> the C contact, I read a value of about 1.6-1.7.
>
> Touching Red to C, and black to B, I read a value of .6-.7.
>
> One thing that definitely doesn't make sense to me about the multimeter:
> In the Ohms section of the dial, there is a '200' position, and a '2k'
> position. As I understand things, this simply adjusts the scale of the
> display, and where the decimal appears. You simply set the knob to
> something that will be in the range of what you are testing. BUT, when I
> tested the components above in the 200 setting, there was no reading,
> yet in 2k (2000) I saw values much smaller than 200, smaller than 2 for
> that matter. The only thing I see that might explain this is the symbol
> next to the 2k is only next to the 2k, none of the other settings. I
> assume this symbol means something relevant to this.
Well, at 200 ohm, it might not have had enough voltage and/or
current to turn a semiconductor on.
RwP
Stephen Jacobs
St...@JacobsHome.org says...
One thing i forgot to ask -
My multimeter also has a 4-contact socket with hFE printed above it, and
ECBE printed below, corresponding to the 4 contacts. I'm guessing this
is for testing transistors? How would I use it, and what does the hFE
stand for?
Ralph Wade Phillips
"Stephen Jacobs" <St...@JacobsHome.org> wrote in message
news:MPG.17cccc929...@news.speakeasy.org...
> One thing i forgot to ask -
> My multimeter also has a 4-contact socket with hFE printed above it, and
> ECBE printed below, corresponding to the 4 contacts. I'm guessing this
> is for testing transistors? How would I use it, and what does the hFE
> stand for?
I forget the derivation, but it's basically maximum DC gain. It's
also known as the "beta" of a transistor (which is easier to pronounce than
'hFE' is ... <grins>)
The actual circuit gain, if below the hFE of the transistor, is
usually set in the ratio of the input resistance to the output resistance.
RwP
Stephen Jacobs
link). I opened up another, older Atari 5200. This one had some slightly
different components, and I've got some side-by-side comparisons online.
Of particular note: where the broken system has a couple of components
labelled 7805a, the older system has a couple of components labelled
MJE-210. The schematic calls for MJE-210s. Assumedly the board was
slightly revised at some point, explaining the discrepancy.
How would I test the 7805a(s) ? FWIW, when I tried to test them before,
the legs were very soft & flexible. This seemed somehow wrong to me. In
my experience things like this are usually stiffer than these were.
-Steve
Ralph Wade Phillips
"Stephen Jacobs" <St...@JacobsHome.org> wrote in message
news:MPG.17cce1a7b...@news.speakeasy.org...
> Added more pictures to website ( http://64.81.193.244 , videogames
> link). I opened up another, older Atari 5200. This one had some slightly
> different components, and I've got some side-by-side comparisons online.
>
> Of particular note: where the broken system has a couple of components
> labelled 7805a, the older system has a couple of components labelled
> MJE-210. The schematic calls for MJE-210s. Assumedly the board was
> slightly revised at some point, explaining the discrepancy.
Of course, the two parts that you see the 7805a on - might be
MJE-210's made in the fifth week of 1978. I really can't tell from here,
but what's on the "transistors" over on the heatsink (to the left of the RF
modulator, that shiny metal thing) on both boards?
>
> How would I test the 7805a(s) ? FWIW, when I tried to test them before,
> the legs were very soft & flexible. This seemed somehow wrong to me. In
> my experience things like this are usually stiffer than these were.
Again, it would be helpful to know what the full number is.
If the newer machine was made in 1978 or 1979, any number such as
"7805" needs to be verified that it's not a date code (which some folks here
might be too young to remember that. Or 74xx logic made in 1974, which had
the same problem!)
RwP
Shaun Davy
My advice would be to get out your mulitmeter and put the black lead in the
"-" socket and the red in the "+" socket, switch on and put on 20V DC range.
Put the black lead on ground which should be on the metal clamp around the
outside of the coax input. now put the red lead on the MJE 210 (and yes in
your pics they do appear to be the MJE 210's) closest to the metal box on
the leg going into board where E is written. now there should be 13 or so
volts on this leg.
Now on the schematic diagram there is something about a "jumper in the plug
in rom cartridge" sounds as if the unit will only attempt to pwer on with
game in the unit, so have a game in the unit.
Now hold the red lead on the same MJE 210 but on the leg that has a C on the
board and press the power button on the atari and release. now there should
be around 13V again on the C leg. if not repeat pressing the button and see
if it makes any difference by pressing and holding the button or anything u
can do to get that voltage to change.
Ok if this test works then it had just ruled out a more complicated section
of circuity. if not (don't be alarmed) then the problem is not in the actual
power supply its self but in the section to switch the power supply on. if u
are careful and confident u can retest this on the other running 5200.
Also can u report back exactly what is written on the MJE 210's on your
machine, check if they have been removed. it looks like they could have
replaced in the picture due to package type and the board looks a bit messy.
u can check on the bottom of the board to see if the solder joint looks
different to the others, as in look messy cause it does on the top from pic.
OK good luck with it!
"Stephen Jacobs" <St...@JacobsHome.org> wrote in message
news:MPG.17cc6224e...@news-remote.speakeasy.net...
Shaun Davy
1 to the right of it) as well almost guaranteed to be exactly the same but
better check anyway.
"Shaun Davy" <shau...@bigpond.com> wrote in message
news:P_K89.11456$g9.3...@newsfeeds.bigpond.com...
Jeroni Paul
them.
You more easily test transistors using the diode test functions of your
multimeter that should be found near the ohm scales.
Jeroni Paul
"Stephen Jacobs" <St...@JacobsHome.org> wrote in
news:MPG.17cccc929...@news.speakeasy.org
Jeroni Paul
> Added more pictures to website ( http://64.81.193.244 , videogames
> link). I opened up another, older Atari 5200. This one had some slightly
> different components, and I've got some side-by-side comparisons online.
>
> Of particular note: where the broken system has a couple of components
> labelled 7805a, the older system has a couple of components labelled
> MJE-210. The schematic calls for MJE-210s. Assumedly the board was
> slightly revised at some point, explaining the discrepancy.
This confirms these components are the MJE-210 transistors, but they're
another model.
What are the texts writen on top of the 7805a? It appears to me something
starting with 'u'?
> How would I test the 7805a(s) ? FWIW, when I tried to test them before,
> the legs were very soft & flexible. This seemed somehow wrong to me. In
> my experience things like this are usually stiffer than these were.
MJE210 is a PNP transistor; for PNP transistors:
Emitter-Base (E-B) should behave like a diode - so use the diode test of
your multimeter to check if it conducts in one direction (positive to
emitter and negative to base) and does not in the opposite direction. A
diode conducts when the multimeter shows a voltage drop of 0.5-0.7V (that
the multimeter shows in milliVolts, so something between 500 and 799). A
diode does not conduct when the multimeter shows nothing (i. e. a 1 in the
left side of the display as most multimeters show).
Okay, now to test the collector: keep whatever probe you have in the base
when the diode Emitter-Base conducts (should be the negative probe but some
multimeters have the probes reversed) and place the other probe in the
collector. The multimeter should show a similar voltage drop as it did in
the E-B test (i.e. between 0.5 and 0.7V). Reverse the probes and check it
now shows no conduction.
Keep one important thing in mind: the rest of the circuit could have an
effect in the test. If you get strange readings in this test remove the
transistor and check it alone. If alone still gives strange readings, it's
probably defective. Or, to aboid soldering work, perform the test on the
known good Atari and compare the results.
Of course these tests must be done with NO power applied to the Atari.
And this could also be of some use: check with the diode test between the
middle and left pins of the 7805 regulator. I've taken a good 7805 and mine
measures like a diode - 0.6V drop in one direction and open in the reverse
direction. I've no idea if all regulators will read the same results.
> -Steve
Good luck,
Jeroni Paul
Jeroni Paul
MJE210 transistors (those bigger cylinders with green background and colours
brown-gray-red-black-(gold?). They seem fuseable resistors, so even though
they don't seem burned it would be wise to check them. Just put your
multimeter in the 200 or 2K ohm scale and place the probes one on each leg
that comes out of these resistors. It should read 182 ohm (or 181 or 183 but
not too far).
Also, compare the voltage on the pins of the MJE210 transistors with the
working Atari. Attach negative probe to the negative of the incoming 13V and
with the positive probe measure voltage on these three legs. Post the
results.
> How would I test the 7805a(s) ? FWIW, when I tried to test them before,
> the legs were very soft & flexible. This seemed somehow wrong to me. In
> my experience things like this are usually stiffer than these were.
Do the pins move where they are held to the board? - these could be bad
solder joints, thus they need resoldering.
Jeroni Paul
"Stephen Jacobs" <St...@JacobsHome.org> wrote in
news:MPG.17cce1a7b...@news.speakeasy.org
Stephen Jacobs
JERON...@terra.es says...
Hi guys,
Sorry I seem to have stopped posting - things have been busy with work,
and I haven't had time the last couple of days to pursue this much.
Wednesday evening I did get some help over the phone from a coworker. It
looks as though the 7805a components (transistors?) that are in the
place on the circuit board that the schematic designates as MJE-210s are
fried. I am going to try and find time this weekend to get a higher-
quality soldering iron than what I have, and some replacement MJE-210s,
and replace them, and see what happens.
So, in advance of that minor adventure, I have a few questions:
1) You guys seem to think the pieces I have that are clearly labelled
7805a aren't transistors, yet the schematic has MJE-210s (transistors,
right?) in that spot. Also, the area on the board for the components is
labelled Q6 & Q7. Obviously I don't know, but I don't think the 7805a is
a date code. It looks more like a part# to me. Also, I guess the parts
could have been in a warehouse for a long time, but the system wasn't
made until 1982 at the very earliest, and right next to the suspect
components is a clear datestamp on another part that reads 1983. Is it
probably OK for me to put MJE-210s in their place? If I bring the
suspect components to an electronics shop, would they be able to
identify them and sell me functionally-equivalent replacements?
2) The current components are soldered to the board in fairly close-
quarters; there isn't a whole lot of room to work in there. Could you
recommend any particular soldering irons, or types of soldering iron, I
should get? When installing the replacement pieces, I currently have 96%
tin, 4% silver Radio Shack lead-free solder, melting temp 430º. I also
have Radio Shack Rosin Core Solder, 60/40, .050. Are either of those OK,
and which should I use? If neither of those is best, what should I get?
--
Steve
Shaun Davy
works, just try to get 2 new MJE 210's and stick them in there, it looks as
if someone has replaced these parts before, possibly with the incorrect ones
As for the soldering iron, if u are going to buy one ask the dude in the
store where u are getting transistors. doesn't need to be anything to flash.
Just a standard iron (not gun). can get away with the cheapest one there
more than likely.
"Stephen Jacobs" <St...@JacobsHome.org> wrote in message
news:MPG.17d0c662...@news.speakeasy.org...
Jeroni Paul
>
> Hi guys,
> Sorry I seem to have stopped posting - things have been busy with work,
> and I haven't had time the last couple of days to pursue this much.
> Wednesday evening I did get some help over the phone from a coworker. It
> looks as though the 7805a components (transistors?) that are in the
> place on the circuit board that the schematic designates as MJE-210s are
> fried. I am going to try and find time this weekend to get a higher-
> quality soldering iron than what I have, and some replacement MJE-210s,
> and replace them, and see what happens.
>
> So, in advance of that minor adventure, I have a few questions:
>
> 1) You guys seem to think the pieces I have that are clearly labelled
> 7805a aren't transistors, yet the schematic has MJE-210s (transistors,
> right?) in that spot.
No, since they are in the same place as the MJE210 I always thought they
were transistors.
> Also, the area on the board for the components is
> labelled Q6 & Q7. Obviously I don't know, but I don't think the 7805a is
> a date code. It looks more like a part# to me.
But this is the only text on it?
> Also, I guess the parts
> could have been in a warehouse for a long time, but the system wasn't
> made until 1982 at the very earliest, and right next to the suspect
> components is a clear datestamp on another part that reads 1983. Is it
> probably OK for me to put MJE-210s in their place? If I bring the
> suspect components to an electronics shop, would they be able to
> identify them and sell me functionally-equivalent replacements?
Watch out they don't sell you 7805 regulators!
You can explain this is a transistor not a voltage regulator, and if they
don't recognize it, then request MJE210.
Could also be someone replaced them before, or even wrongly put there 7805
voltage regulators !?!
Jeroni Paul
Stephen Jacobs
copy was sent to the cited author.]
In article <ak7rs3$o24$1...@nsnmpen2-gest.nuria.telefonica-
data.net>, JERON...@terra.es says...
I've replaced the 2 7805a(s) with a pair of MJE-210s. The
unit still doesn't power on, but if I short the Collector &
Base of each of the MJE-210s it will power up. For the most
part, it seems to operate fine after that, with one
exception - the controller (in jack 1, all I've tried)
doesn't seem to be calibrated quite right - in Pole
Position I could not upshift (Joystick UP), in Defender I
could turn Left, but not Thrust left (wouldn't go far
enough left?), and in Missile Command I could move the
cursor right, but it would not go all the way to the right
side of the screen, stopping maybe 2/3 of the way to the
right.
I had the pins on the MJE-210s shorted by simply placing
the tips of 2 multimeter probes between the legs. It was
not a secure connection, and inserting/removing a cartridge
or plugging in a controller obviously caused the power to
fluctuate as the probes momentarily made and lost contact.
Is it likely the various controller issues were just due to
flaky power (like what people coined 'frying' in regards to
the 2600 - if you rapidly flipped the 2600 power on & off,
due to the unsteady power the programs would malfunction
and produce unintended results on-screen. In Space
Invaders, for example, you could have 2 missiles
simultaneously onscreen instead of one) ?
Unfortunately I haven't had time to pursue this project
much over the last 2 weeks, but it hasn't been forgotten.
I'll continue to keep you guys updated as any updates
happen.
Thanks for any help,
Steve
Jeroni Paul
I think there are more bad parts: my first candidate is the 4013 integrated
circuit (U29). Since it runs out of the unregulated voltage and it is easily
damaged, it is likely to be the cause. It's very cheap (probably cheaper
than the transistors you bought)
So now please, test the 4013: first attach negative probe of your voltmeter
to an available ground (for example pin 7 of 4013 should be ground). Measure
pin 14 has around 14V. Check pin 4 has around 13V when Power push depressed
and 0V with Power push pressed. Check pin 6 has 0V with Power push depressed
and around 13V with power push pressed. If that is OK the inputs to 4013 are
fine, so let's check outputs:
Check voltage in pin 1: it must be around 14V when Power push is pressed and
0V when is depressed (this acts as a push debouncer). Pin 1 is connected to
pin 11 so they must give the same results. Check pin 10 has 0V (reset input)
and now look at pin 13. Pin 13 behaves this way: it should be 0V the first
time you plug the power. The first time you press the Power button pin 13
must change to 14V and remain that way until you press again the Power
button. Then it remains at 14V until you press Power button again, and so
on...
If that test fails (and pin 14 there are 14V (supply to the 4013) and pin 10
there are 0V (reset signal)) the 4013 is defective. Notice that 4013
activates the two 2N3904 transistors, and these in turn switch the MJE210.
If 4013 fails to start with, it'll cause your problem. If 4013 works in the
above test then check the two transistors 2N3904 (numbered 8 and 9) and
associated resistors. There are no more things that can cause a missing
drive to the base of MJE210.
Start fixing this problem before trying to run a game. The system probably
does not initialize correctly thus causing all the problems you describe.
The sympthoms you mention sound normal to a digital system where the supply
is not stable.
As for the calibration problem, check that both 7805 regulators are working
and output 5V (maximum deviation between 4.5V and 5.5V). If some outputs a
higher voltage that could cause your problem.
Good luck,
Jeroni Paul
"Stephen Jacobs" <St...@JacobsHome.org> wrote in
news:MPG.17e12890e...@news-remote.speakeasy.net
Jeroni Paul
http://www.hanssummers.com/electronics/datasheets/pixs.gif
Good luck,
Jeroni Paul
"Jeroni Paul" <JERON...@terra.es> wrote in
news:al82in$emm$1...@nsnmpen2-gest.nuria.telefonica-data.net
Stephen Jacobs
copy was sent to the cited author.]
In article <WcMd9.207141$6K3.1...@telenews.teleline.es>,
JERON...@terra.es says...
Thx! I'll try to get to that as soon as I can, now that I
know where to look & what to do. I should point out that
the power switch is a momentary-switch, in case that makes
a difference. In other words, it hasn't got an 'on'
position & an 'off' position. While it does make a tactile,
satisfying click when pressed, it functions more like a
modern laptop computer's power switch in that it is
physically in the same position whether the unit is on or
off. I'm guessing (but I think you'll know) that the 4013
chip is actually doing the real switching.
Steve
Jeroni Paul
> [This followup was posted to sci.electronics.repair and a
> copy was sent to the cited author.]
>
> know where to look & what to do. I should point out that
> the power switch is a momentary-switch, in case that makes
> a difference. In other words, it hasn't got an 'on'
> position & an 'off' position. While it does make a tactile,
> satisfying click when pressed, it functions more like a
> modern laptop computer's power switch in that it is
> physically in the same position whether the unit is on or
> off.
Exactly what I assumed, that is why there is a 4013 there.
> I'm guessing (but I think you'll know) that the 4013
> chip is actually doing the real switching.
Exactly. Since it's a low power device it uses transistors 2N3904 and MJE210
to switch power to voltage regulators.
> Steve
Jeroni Paul
Stephen Jacobs
JERON...@terra.es says...
OK, I performed the first few tests you suggested. How do pros do these
tests? I found myself needing 3 hands. I had my wife assist me for 3 of
the tests, and then she went to bed, which is why I didn't perform the
others.
Anyway, I'm pretty sure my results will shed enough new information to
give me something to work with:
I set the voltmeter to read DC volts, with the scale adjusted to a range
of 20v.
Assuming I read the pin numbering right, I held negative to pin 7 for
each test. I then touched positive to the other pins and read the values
on the display.
Pin 14: about 12.2v
Pin 4: about 11v. When the power button was pressed, the power dropped
to around 2 or 3v, and then slowly went down to 0, bouncing up and down
a little bit after reaching 0. When the button was released the reading
went back up to about 11v.
Pin 6: 0v, about 10v when the power button was pressed.
That covers your input tests. My readings didn't quite match what you
described, so I'm thinking the chip is shot.
In your paragraph on the outputs, I only tested Pin 13, due to my lack
of a 3rd hand. You indicate that immediately after connecting power,
before the system has initially been turned on, Pin 13 should read 0v.
I disconnected the power and waited about 15 seconds. I then reconnected
the power. THEN, I touched the negative probe to Pin 7. Applying the
positive probe to Pin 13 caused the relay in the TV-Switchbox to click,
and the power LED illuminated. I was startled and immediately pulled the
probe off the pin.
It seems to me this action turned the unit on. I don't know for certain,
though. The switchbox is not presently connected to the TV, so naturally
I can't know what actually happened.
At this point should I get a 4013 and try to replace the chip that is
currently on the board? Is it likely I might be able to find another
4013 in any common consumer electronics? Off the top of my head I can
scavenge parts from a very old VCR, or from a 4 year old automobile CD
Changer I've got that is mechanically broken. i can probably find other
dead electronics to rip apart as well.
Thanks,
Steve
Stephen Jacobs
copy was sent to the cited author.]
Just another bit of education for me, if you've got the
patience for it -
All this time, when looking at the schematic, I've been
assuming there are 2 physical 4013 components in the
circuit. I saw one 4013 chip (IC) on the board near the
power switch. Upon closer examination, I notice the
schematic has what appears to be numbering of each
connection to the 4013s drawn there. The numbers are not
duplicated between the 2 representations on the paper. Are
the 2 4013s drawn on the schematic actually the same
physical component? (This seems obvious to me now.)
AND, I don't see any marking for Pin 2 - is it simply not
present on the schematic because it isn't connected to the
circuit at all?
Thanks,
Steve (dense, but trying...)
In article <MPG.17e1de926...@news.speakeasy.org>,
St...@JacobsHome.org says...
Dbowey
component? >>
Probably, yes. The only way I have ever bought them is in a 14 pin package
with two independant circuits in the pkg.
<< AND, I don't see any marking for Pin 2 - is it simply not
present on the schematic because it isn't connected to the
circuit at all? >>
Pin 2 is the "NOT Q" output of the first 4013 half. It is too common to see
pins that are not used, ignored..... a sloppy practice.
Don
Jeroni Paul
See below:
"Stephen Jacobs" <St...@JacobsHome.org> wrote in
news:MPG.17e1de926...@news.speakeasy.org
> OK, I performed the first few tests you suggested. How do pros do these
> tests? I found myself needing 3 hands. I had my wife assist me for 3 of
> the tests, and then she went to bed, which is why I didn't perform the
> others.
Grins.
I attach negative probe to an available ground permanently with clips. Then
use positive ground with one hand and push the Power push with the other.
> Anyway, I'm pretty sure my results will shed enough new information to
> give me something to work with:
>
> I set the voltmeter to read DC volts, with the scale adjusted to a range
> of 20v.
>
> Assuming I read the pin numbering right, I held negative to pin 7 for
> each test. I then touched positive to the other pins and read the values
> on the display.
>
> Pin 14: about 12.2v
It is correct. I said 14V because this is what is marked in the schematic
but this voltage isn't critical. 4013 can work from 3V to 18V. And since the
wrong adapter was used, if the supply exceeded 18V the 4013 was probably
destroyed.
> Pin 4: about 11v.
For the same reason as above, if supply would be 14V then voltage here would
be 13V. Since the actual supply is 12V the voltage here is 11V which is
correct and will trigger the 4013 correctly.
> When the power button was pressed, the power dropped
> to around 2 or 3v, and then slowly went down to 0, bouncing up and down
> a little bit after reaching 0. When the button was released the reading
> went back up to about 11v.
>
> Pin 6: 0v, about 10v when the power button was pressed.
Seems correct. 10V will also trigger the 4013
> That covers your input tests. My readings didn't quite match what you
> described, so I'm thinking the chip is shot.
Since the inputs check out correct one concludes the chip is shot since it's
not outputing the proper signals.
> In your paragraph on the outputs, I only tested Pin 13, due to my lack
> of a 3rd hand. You indicate that immediately after connecting power,
> before the system has initially been turned on, Pin 13 should read 0v.
>
> I disconnected the power and waited about 15 seconds. I then reconnected
> the power. THEN, I touched the negative probe to Pin 7. Applying the
> positive probe to Pin 13 caused the relay in the TV-Switchbox to click,
> and the power LED illuminated. I was startled and immediately pulled the
> probe off the pin.
>
> It seems to me this action turned the unit on. I don't know for certain,
> though. The switchbox is not presently connected to the TV, so naturally
> I can't know what actually happened.
4013 controls the Atari through pin 13. You
should try to keep the probe and see if the Atari really turns on. If this
is true that means that all the 2N3904 transistors are fine, and so the
problem is the 4013. All you can do from that pin is turn the machine on and
off. Probably your voltmeter pulls pin 13 to ground thus causing the machine
to start.
> At this point should I get a 4013 and try to replace the chip that is
> currently on the board?
Before that try to keep the DC meter to measure voltage on pin 13: then
press the Power push to see if it makes any difference. If the 4013 was
fine, the little load of a voltmeter would not cause any change and you
would see the expected result.
On the other hand it is very easy to influenciate a state change on an
unconnected input. It could be that it turned on due to some input
unconnected and influenced by you working near it. The problem probably is
some internal break.
> Is it likely I might be able to find another
> 4013 in any common consumer electronics?
> Off the top of my head I can
> scavenge parts from a very old VCR, or from a 4 year old automobile CD
> Changer I've got that is mechanically broken. i can probably find other
> dead electronics to rip apart as well.
Consider the time you'll spend looking for it and then desoldering will not
compensate the cost of a new one. You may try a search if you're so
inclined.
CD4013, HEF4013, MC14013, TC4013, etc. are names that designate the same IC.
You can take your 4013 and go to the same shop where you bought the
transistors. They should have it.
In the shop you should ask for '4013' and they should know. If they seem to
doubt you may be more specific: this is a CMOS dual D-type flip-flop.
'4xxx' are a well known series of CMOS digital circuits.
> Thanks,
> Steve
Greetings,
Jeroni Paul
Jeroni Paul
> [This followup was posted to sci.electronics.repair and a
> copy was sent to the cited author.]
>
>
> Just another bit of education for me, if you've got the
> patience for it -
You're welcome.
> All this time, when looking at the schematic, I've been
> assuming there are 2 physical 4013 components in the
> circuit. I saw one 4013 chip (IC) on the board near the
> power switch. Upon closer examination, I notice the
> schematic has what appears to be numbering of each
> connection to the 4013s drawn there. The numbers are not
> duplicated between the 2 representations on the paper. Are
> the 2 4013s drawn on the schematic actually the same
> physical component? (This seems obvious to me now.)
Yes. This is a dual D-type flip-flop. 'dual' means there are two D-type
flip-flops in the same chip.
> AND, I don't see any marking for Pin 2 - is it simply not
> present on the schematic because it isn't connected to the
> circuit at all?
Pin 2 is the inverted signal output in pin 1. The circuit doesn't need this
signal so is left unconnected.
> Thanks,
> Steve (dense, but trying...)
Jeroni Paul
Stephen Jacobs
JERON...@terra.es says...
> Hi Stephen,
>
> See below:
>
> "Stephen Jacobs" <St...@JacobsHome.org> wrote in
> news:MPG.17e1de926...@news.speakeasy.org
>
>
> It is correct. I said 14V because this is what is marked in the schematic
> but this voltage isn't critical. 4013 can work from 3V to 18V. And since the
> wrong adapter was used, if the supply exceeded 18V the 4013 was probably
> destroyed.
>
> > Pin 4: about 11v.
>
> For the same reason as above, if supply would be 14V then voltage here would
> be 13V. Since the actual supply is 12V the voltage here is 11V which is
> correct and will trigger the 4013 correctly.
>
> > When the power button was pressed, the power dropped
> > to around 2 or 3v, and then slowly went down to 0, bouncing up and down
> > a little bit after reaching 0. When the button was released the reading
> > went back up to about 11v.
> >
> > Pin 6: 0v, about 10v when the power button was pressed.
>
> Seems correct. 10V will also trigger the 4013
>
> Since the inputs check out correct one concludes the chip is shot since it's
I tried again tonight to test Pin 13. It no longer shows any voltage at
all, whether the machine has been powered on or not, whether or not the
power button is pressed, etc... Pin 13 shows 0 volts, consistently, no
matter what. Could I have destroyed it last night? It was late and I was
tired; perhaps I accidentally shorted it when I tested it? or maybe it
was already damaged, and I just pushed it over the edge?
Jeroni Paul
> I tried again tonight to test Pin 13. It no longer shows any voltage at
> all, whether the machine has been powered on or not, whether or not the
> power button is pressed, etc... Pin 13 shows 0 volts, consistently, no
> matter what. Could I have destroyed it last night? It was late and I was
> tired; perhaps I accidentally shorted it when I tested it? or maybe it
> was already damaged, and I just pushed it over the edge?
Ok, showing always 0V confirms the 4013 is defective and has to be
replaced.
This makes more sense: I couldn't belive a digital voltmeter pulling
pin 13 anywhere to start up the machine. You probably shorted pin 13
to pin 14. And you did not damage the chip doing that. I've done this
practice many times while working with these 4xxx chips: you can pull
an output to V+ or ground momentarily without any damage to the chip.
It's a bit rude but you sure did not damage the IC doing that.
Actually this is a good way to test the Atari. Short pin 13 to pin 14
only momentarily and confirm the Atari starts up. If it does it is a
sign the Atari works great and the 4013 is (should be) the only
defective part.
Good luck,
Jeroni Paul
ehf...@gmail.com
> I have an Atari 5200 videogame system. The motherboard is dated (c)1982,
> and a stamped label on the RF shield is dated 1983.
>
> The system does not power up.
>
> Surrounding many of the solder points on the underside of the
> motherboard is some kind of residue that looks like some sort of brown
> syrup-ish substance, a bit like old Coca-cola. Might be nothing.
>
> The previous owner indicated that he received the system with the
> incorrect power supply. He obtained the correct power supply, and never
> got the machine to work.
>
> I noticed 3 components, labelled C30, C32, & C33. These components look
> like discs, mostly olive green, with shiny black coloring at the tops.
>
> A) I'm guessing these are capacitors - am I right?
> B) Are these components supposed to be all green, and is the black on
> the top indicative that they've fried?
> C) Is it reasonable to conclude that the wrong power supply was hooked
> up, and it fried these capacitors? If so, could I probably get the
> system working by replacing these capacitors?
> Thanks for any help,
> Steve
Allodoxaphobia
> On Thursday, August 15, 2002 at 12:30:56 AM UTC-4, Stephen Jacobs wrote:
>> I have an Atari 5200 videogame system. The motherboard is dated (c)1982,
> I am so sorry if I am sounding like a complete novice in this, but I
> AM ONE!
Why _the hell_ did you reply to a FOURTEEN-YEAR OLD posting instead
of starting a new one to request help for your problem(s)?
sheeesh!! google groopers!!
Rheilly Phoull
it would seem you havent googled "repair atari 5200" ??
Theres a heap of posts on that one !!