Omega Race repair questions
Shaggy
working when I picked it up (which is why I got it cheap). There is glow
in the neck of the tube but the spot-killer LED is on. Also, the fuse in
the PSB glows. Should it do that??? I haven't had any luck finding a
troubleshooting guide online like I did for my Williams PSB. Can anyone
tell me how to test the PSB? Should I just test the voltage where it
comes into the mother board and logic board?
Thanks,
shaggy
zektor
Un plug the monitor for now as you could fry it if the game pcb isn't
working properly. Download the game manual then test the voltages on
the power supply board to make sure they are within spec. If the
voltages check out then place the game in test mode by flicking the
switch on the coin door to test, you will hear a series of tones if
you have bad ram, the last tone will indicate which ram is bad, the
manual will tell you which IC it could be. If the board doesn't enter
self test and the voltages are correct it's a bit more complicated.
Shaggy
post my results. Should I leave the power supply board connected to the
game board while I am testing the voltages?
zektor
>
> - Show quoted text -
Yes you will need to for the sense wires, I do a mod similar to the
ARII mod for the Atari on the Omega Race power supply. If you remove
the power PCB and look at the trace side there is a 9 pin connector
marked "C1" you will see 2 lots of holes for jumper wires..they
weren't installed at the factory but you can just solder in 2 wire
links, if you look on the scematics its clear to see. Like on the
Atari games if you get dirty connection at the game PCB the power
board ramps up the voltage by mistake in turn frying the game. Once
you have the jumper wires in place you can test the power board with
the game board disconnected.
Good luck!
Shaggy
transistors and the capacitors. I had to replace the fuse as even though
it looked ok it tested bad. The output voltages on the voltage
regulators is good, 12v and 5v. The LED on the mainboard which was not
lit before now comes on which I assume is just indicating that it is
getting power.
But the spot-killer LED on the monitor is still on so there is no picture.
I would assume that if it was a problem with the monitor only, that I
could play the game blind correct? Well, I can't get the game to do
anything by tripping the coin switches. Not a peep. So wouldn't this
indicate a problem with the mainboard? When I got the game, there was
some minor battery acid damage. I did not think it was bad enough to
take out any components but maybe I am wrong.
The acid only made it to the SN74LS245N just under the battery and the 4
resistors and 2 diodes in between. I took a fiberglass pen to them and
the legs all cleaned up pretty well. I guess I will go ahead and replace
them though just in case.
Anyone have any other suggestions?
Thanks,
shaggy
On 3/5/2010 3:13 AM, zektor wrote:
John Robertson
> Ok. The power supply is working now. I replaced the three main
> transistors and the capacitors. I had to replace the fuse as even though
> it looked ok it tested bad. The output voltages on the voltage
> regulators is good, 12v and 5v. The LED on the mainboard which was not
> lit before now comes on which I assume is just indicating that it is
> getting power.
>
> But the spot-killer LED on the monitor is still on so there is no picture.
>
> I would assume that if it was a problem with the monitor only, that I
> could play the game blind correct? Well, I can't get the game to do
> anything by tripping the coin switches. Not a peep. So wouldn't this
> indicate a problem with the mainboard? When I got the game, there was
> some minor battery acid damage. I did not think it was bad enough to
> take out any components but maybe I am wrong.
>
> The acid only made it to the SN74LS245N just under the battery and the 4
> resistors and 2 diodes in between. I took a fiberglass pen to them and
> the legs all cleaned up pretty well. I guess I will go ahead and replace
> them though just in case.
>
> Anyone have any other suggestions?
>
> Thanks,
> shaggy
OMEGA RACE is a sad case - usually when you get any battery leakage the
stuff gets into everything and the board is very hard to bring back to life.
To start I would check all EPROM sockets near the battery, heck just
replace the IC sockets near the battery...
After that, if still dead, then you need some Technical Tool power -
borrow/buy a Fluke 9010 and a Z80pod and learn about troubleshooting CPU
boards...
Leave the monitor unplugged (no point in blowing it up too) when testing
until you get game sounds and both X and Y AC outputs (varies from 1 -
3VAC unless in self-test when it should be stable) from the board.
You did wash the board with vinegar/water and then rinse really well?
John :-#)#
>
> On 3/5/2010 3:13 AM, zektor wrote:
>> On Mar 4, 2:32 pm, Shaggy<cardinalsfan...@gmail.com> wrote:
>>> Finally getting around to working on my Omega Race upright. It wasn't
>>> working when I picked it up (which is why I got it cheap). There is glow
>>> in the neck of the tube but the spot-killer LED is on. Also, the fuse in
>>> the PSB glows. Should it do that??? I haven't had any luck finding a
>>> troubleshooting guide online like I did for my Williams PSB. Can anyone
>>> tell me how to test the PSB? Should I just test the voltage where it
>>> comes into the mother board and logic board?
>>>
>>> Thanks,
>>> shaggy
>>
>> Un plug the monitor for now as you could fry it if the game pcb isn't
>> working properly. Download the game manual then test the voltages on
>> the power supply board to make sure they are within spec. If the
>> voltages check out then place the game in test mode by flicking the
>> switch on the coin door to test, you will hear a series of tones if
>> you have bad ram, the last tone will indicate which ram is bad, the
>> manual will tell you which IC it could be. If the board doesn't enter
>> self test and the voltages are correct it's a bit more complicated.
>
--
(Please post followups or tech inquiries to the newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."
zektor
>
> - Show quoted text -- Hide quoted text -
>
> - Show quoted text -
Have you tried the self test switch? Make sure the volume is up or you
may not hear the beeps, also the leds on the start switched can flash
out the bad ROM/RAM if its a video RAM and unable to produce video on
screen.
LyonsArcade
but I was able to repair a badly damaged board. I switched 19 sockets
and chips, and 16 resistors, 4 diodes. The game is booting and
coining up, now i"m on the monitor.
I'm just letting you know, you can do it. I would replace the sockets
near the end of the extent of the battery damage, they will likely
still have corroded pins even though you can't see it from the top.
Shaggy
the SN74LS245N as they are out but have them on order. I started
removing the components affected by the acid damage. The acid seems to
make the whole process more difficult. When I would melt the solder, a
black sludge would sometimes seem to form. I don't think it was just the
flux.
I also had problems with a new solder braid I had bought. It just didn't
seem to draw the solder up into it like my old braid. I wondered if that
had to do with the corrosion but I found a small piece of the old braid
and it worked just fine. I am going to pick up some more tomorrow.
Pretty sure I got the old stuff from Radio Shack.
It didn't help that when the resistors and diodes were installed, they
bent the leads at an almost 90 degree angle making them harder to remove.
I was just wondering if anyone has any advice that might help me in
dealing with the corrosion.
A picture of the board before I began any of this is here:
http://www.wiredtechnician.com/omega.htm
-Shaggy
vintagegamer
>
> - Show quoted text -
I need to bookmark this for when I start working on my Omega Race!
VG
vintagegamer
> Also, the fuse in
> the PSB glows. Should it do that???
>
> shaggy
Shaggy, did this go away when you replaced the capacitors and
transistors on the PSB? Mine does the same thing when I have the game
PCB hooked up. If the game PCB is not hooked up, that fuse does not
glow.
LyonsArcade
Man yours looks like a cakewalk compared to mine! I'm getting lots of
lightening all around the screen when I hook mine up now, can't get it
to go into test, so I"m going to start by testing the ram I replaced,
I used some of the used chips. Luckily I replaced all the sockets so
it's fairly simple now.
Shaggy
and transistors, I hooked it all back up and it didn't glow, but the LED
on the mainboard still didn't light up either. I started testing and the
input leg of the 5v voltage regulator wasn't showing anything so I
tested the fuse and it had no continuity even though it visibly looked
ok. So I had to order new fuses from Mouser (or Digikey, I forget which)
since I could not locate it locally. But I now get a steady 5v and 12v
with no glowing fuse.
Let me know if you want any part numbers and prices of what I ordered.
Paladin
that I sold a while ago to open up some space, but another one popped
up 10 minutes from my house and I had one open spot so I picked it
up. The seller said it gets through the first 4 sections of the test
menu before locking up. I pulled the board before even trying it due
to seeing the dreaded battery still on the board. I've never done
battery damage repair before, so it's encouraging to see other folks
giving it a shot.
I checked Mouser for the chips that have visible damage, but most of
them were listed as backordered with a couple unavailable. I searched
around a little and found American Microsemiconductor. They had all
of the chips I needed, although they don't have the nice pictures like
Mouser. I've got my fingers crossed that they'll be the correct size/
form factor. It was only $22 shipped for 10 74LS chips and 5 2114
RAM.
I've been looking around the web for acid repair tips (learning that
it's actually not acid), and have found some people just clean up the
flaking, brush with vinegar/water and then plug in the board to start
troubleshooting. Others completely replace all chips that show damage
before plugging it in. I was curious what the folks here think. Some
of the chips on my board don't look too bad, just some of the cracking
at the pin to board solder joint. I'll be getting a fiberglass pencil
to see what they look like when I clean them up. If they clean up OK
and meter out with continuity should I leave them, or go ahead and
replace since I'll have the chips?
Pics of my board can be seen here:
http://home.comcast.net/~dark.paladin/omega2
You can see the top 3 chips under the battery that are pretty bad.
Not shown are the 7 chips at the bottom of row E, odd the way the
damage skipped from one row to the other and bypassed a couple chips.
Since this is my first attempt, I've decided to go ahead and do the
top chip that's in the worst shape first. I figure if I'm going to
screw one up that'll be it, so I may as well start there.
I'll post pictures and results as I go for posterity.
Tom
zektor
That's actually a really clean board, you should see some the boards I
have. Vinegar and baking soda mixed applied with an old toothbrush
around the damaged area then rinse with distilled water and dry out on
a low heat in the over or a warm place. I'd just replace that 74245
and give it a go, you will most likely get some ram errors, they are
easy enough to swap out.
Good luck!
Paladin
goosneck lamp with built in magnifier along with sockets, a fiberglass
pencil and some trace repair wire - none of which I've used before.
Everything went extremely well, so well that I didn't need to use the
trace repair wire.
Since the repair of the top of the board worked so well, I think I'll
also do the worse of the chips in the middle of row 2 as well. I've
got the chips on the way, so I may as well keep going.
Pictures have been added to my webpage listed above.
Paladin
cleaning the board and going over the pins with the fiberglass pencil,
but if you look at the pictures you'll see quite a bit of gunk that
was under the chips. There are 3 more that I've decided to just leave
alone until I get my replacement chips in. I don't think they're too
bad, so if the game works I'll leave them be but keep the replacement
chips and sockets with the game just in case.
Getting close!
Paladin
look OK, but nothing on the screen. After a minute of being powered
on, the coin meter starts tripping over and over and some lightning on
the screen. I unplugged the monitor so I don't fry it. Just now I
got 2 beeps from the speaker after unplugging the coin meter, and a
couple of the start buttons are flashing at a constant rate.
Paladin
replaced them and still no go.
Then the disaster happened, I was checking the voltage regulators and
shorted one. Spark, zap! Now I'm toast. No tools or knowledge on how
to find out what I fried.
And here I was doing to well with the socket replacements. Oh well..
Paladin
I replaced the 7812 that I shorted, but the fuse still blows on power
up. Not sure what I've fried, game board power board or both. Funny
thing is, I had removed 4 RAM chips but only put back the 3 in the
sockets I replaced. I had been trying to run it with a missing RAM
chip when I fried it! I'm taking a break on the game until next week.
zektor
Maybe you blew a fuse on the power supply board, don't worry too much
it happens to us all. Take alook at that section the schematics and
check the volatges at the input of the regulators before checking the
output. You will get it running in the end.
Paladin
I just played a game of Omega Race!!
I found that I had blown the diodes at D113 and D114 when I zapped the
regulator. I was confused because the manual stated they were IN4004
diodes, but they're the glass type. A local collector friend informed
me that diodes have come in different packages over the years, and
that I could use the 'normal' black plastic type that can be found at
Radio Shack. I replaced the 2 diodes, and also the 5v regulator since
it looked like it was connected to the diodes.
I powered the game up with the switch in test mode with the monitor
unplugged and didn't hear any beeps or see the LED's flashing, so I
thought I still had a problem. I then tripped the coin mechs and was
rewarded with sound and LED's. I started a game and could hear
gameplay from the left speaker! I then powered it down and plugged in
the monitor and saw that it was indeed passing all the self tests. I
then took it out of test mode and started a 2 player game. While it
was playing I adjusted the right speaker volume, and now have a
completely working game!
The picture is a bit too wide and the image is pretty shaky, so I'll
be ordering a cap kit.
I've done 4 or 5 cap kits before and replaced a few sockets, but never
dealt with corrosion before. I'm simply amazed that I was able to get
this game up and running!
Tom
protoVision
Great to see so many people bringing Omega Races back from the dead.
Highly under rated game in my opinion and one of my favorites.
Paladin
the PDF manual, these should be .01 MF 50v ceramic caps. On the board
I repaired there are diodes in those 3 positions, in the spare board I
picked up to try and fix there are resistors. I found a web page
where someone repaired a board, and they had resistors there but
changed them to the caps listed in the manual.
I'm not very good with schematics and haven't traced where they go,
but was wondering why a game board would seem to work whether it had
caps, resistors or diodes in those locations.