HP 3310B Malfunction Generator

[rickman]

I bought this thing some 10 years ago used and it has worked ok, mainly
as an audio generator. I fired it up the other day and the upper ranges
seem to output a funky sine wave now. The 10 kHz and 100 kHz ranges
output a distorted waveform that does a direction reversal a little bit
after going negative of the midpoint. It almost looks like a rectified
sine wave, but the waveform is more than half a cycle. I don't see any
issues on the other waveforms.

I can play with the range switch and find that turning it slowly can
have an impact on the point of the waveform where the reversal occurs.
But it doesn't really feel like a switch problem. I would disassemble
the switch to see if there are mechanical issues, but it is one of those
multi-gang wafer switches with components mounted directly on it and
each gang is soldered to the board, a real nightmare to remove. This
thing was made to never break, not to be repaired.

I don't have any info on it. The circuit board has some dozens of
transistors, a couple of what are likely op amps (metal cans) and well
over a hundred passives. I don't know where to begin trying to fix
it... other than connectors and switches are the primary point of
failure. But even removing and reseating boards looks like a bear in
this thing.

Any suggestions on ways to repair this?

I saw the other thread on new units and had looked at some of the little
$8 boards on eBay. Funny that there isn't much in between the $8 boards
and the $400 boxes. I would have thought this is something that could
be done very inexpensively these days. I would use a PC audio output
but my signal is outside the 20 kHz upper limit of audio outputs.

Maybe I'll add a simple sig-gen to the prototype circuit I'm building.
Lots more than $8 of effort, but I'll know what I'm getting.

Rick

[Jamie]

Caps..and power supply.

Jamie

[David & Cheryl Denslow]

"Jamie" <jamie_ka1lpa_not_v...@charter.net> wrote in message
news:tnZMs.134394$pV4....@newsfe21.iad...

Operator and Service Manual for P 3310A/B is available here:
http://cp.literature.agilent.com/litweb/pdf/03310-90003.pdf

[tm]

"rickman" <gnu...@gmail.com> wrote in message
news:ke1n0i$97l$1...@dont-email.me...

Service manual here:

http://www.home.agilent.com/agilent/techSupport.jspx?searchT=3310b&id=3310B:epsg:pro&pageMode=OV&pid=3310B:epsg:pro&cc=US&lc=eng

As always, check the power supplies first.

Then RTFM

[Tim Williams]

Not knowing the 3310 offhand, I thought for a moment you were talking
about a piece of test equipment which intentionally generated malfunctions
for testing purposes.

Hey, it's HP, who knows what kind of stuff they made!...

Tim

--
Deep Friar: a very philosophical monk.
Website: http://seventransistorlabs.com

"rickman" <gnu...@gmail.com> wrote in message
news:ke1n0i$97l$1...@dont-email.me...

[WoolyBully]

On Sun, 27 Jan 2013 00:21:32 -0600, "Tim Williams"
<tmor...@charter.net> wrote:

>Not knowing the 3310 offhand, I thought for a moment you were talking
>about a piece of test equipment which intentionally generated malfunctions
>for testing purposes.
>
>Hey, it's HP, who knows what kind of stuff they made!...

That is kinda funny.

Except for the top post.

[Michael A. Terrell]

Tim Williams wrote:
>
> Not knowing the 3310 offhand, I thought for a moment you were talking
> about a piece of test equipment which intentionally generated malfunctions
> for testing purposes.
>
> Hey, it's HP, who knows what kind of stuff they made!...

They left that market to Wavetek. :(

[rickman]

On 1/27/2013 1:21 AM, Tim Williams wrote:
> Not knowing the 3310 offhand, I thought for a moment you were talking
> about a piece of test equipment which intentionally generated malfunctions
> for testing purposes.
>
> Hey, it's HP, who knows what kind of stuff they made!...

Lol!

I don't care if you top post, but in this case your sig made all of my
post disappear... even better, I didn't have to snip! I'll try top
posting in some of the idiot threads that are so popular here. That
should encourage others to trim a bit... lol

Rick

[rickman]

On 1/26/2013 6:48 PM, David & Cheryl Denslow wrote:
> "Jamie"<jamie_ka1lpa_not_v...@charter.net> wrote in message
> news:tnZMs.134394$pV4....@newsfe21.iad...
>>
>>

>> Caps..and power supply.
>>
>> Jamie
>>
>
> Operator and Service Manual for P 3310A/B is available here:
> http://cp.literature.agilent.com/litweb/pdf/03310-90003.pdf
>
>

Thanks. I'll take a look at it. I guess I'm just intimidated by the
disassembly job alone.

It doesn't really look like a PSU issue to me. I would suspect the
switches, but when I work them it just doesn't feel like that's the
problem. The unit has tons of test points so that should make it easier
to see what is going on.

Rick

[Jamie]

I am not sure the age of that unit but I hope it's newer than the tube
era :) A LCR meter would serve you will, along with a DMM.

Oh, and lets us not for get to use a scope on the power supply for cap
ripples and possible linkage in selenium devices and maybe germanium.

Jamie

[rickman]

Thanks for the suggestions, after several folks have said to check power
I guess I'd better do that. But what's with the selenium and germanium
devices? This thing wasn't built in the 50's I'm pretty sure. What do
you mean about "linkage"? Do you mean leakage?

Rick

[Robert Baer]

I have an HP 3312A Function Generator, and the manual.
The looks are quite different, but the general operation should be
very similar.
Basically, it starts with a triangle / square generator,and the sine
is created with a DFG from the triangle.
So,your sine waveform problem is due to a bad diode or resistor in
the diode / resistor chain on the polarity side where you see the defect.
I could scan and send diagrams as need.

[Robert Baer]

[Robert Baer]

NOTE: The OP _only_ complained about the sine output, and mostly at
higher frequencies; definitely not PS oriented; prob is in one of the
DFG chains.

[Robert Baer]

Tim Williams wrote:
> Not knowing the 3310 offhand, I thought for a moment you were talking
> about a piece of test equipment which intentionally generated malfunctions
> for testing purposes.
>

Reminds me of the Missing Pulse Generator used in the Nike/Ajax
missle test van....

[tm]

"Robert Baer" <rober...@localnet.com> wrote in message
news:n4lNs.128399$Id.3...@newsfe24.iad...

So you would not recommend first checking the power supplies on a 40+ year
piece of test equipment before doing any follow-up trouble shooting? Even
when it is a well known fact that electrolytic capacitors that old are often
found degraded.

Oh well, whatever.

[rickman]

Hey, that is one of the "rules of thumb" for repairing any circuit fault
in my opinion. First check the supplies, then if a digital circuit,
check the clocks. They are fast, easy checks to make.

I think Robert is saying he has some insight into the failure based on
the symptoms, so maybe the PSU can be skipped this time. I will be
looking at the manual I download and if it has good info on the test
points, I'll be checking the power supplies.

Thanks,

Rick

[rickman]

Oh, how long has it been missing?

lol

Rick

[Tim Williams]

"rickman" <gnu...@gmail.com> wrote in message

news:ke4h9k$jqe$1...@dont-email.me...

> I don't care if you top post, but in this case your sig made all of my
> post disappear... even better, I didn't have to snip! I'll try top
> posting in some of the idiot threads that are so popular here. That
> should encourage others to trim a bit... lol

That's the spirit! ;-)

Plus it's nice if you're just slapping something on which isn't very
relevant to quoted material. Saves time, makes it easy to read.

[Michael A. Terrell]

Listen to Maynard Philbrick at your own risk.

HP used germanium transistors in the '60s designs, like everyone
else, then moved to silicon. They weren't penny pinching, they were
cutting edge designs.

You should always verify the power supply is in spec on test
equipment before doing anything else. Slight errors are compounded, and
can cause you all kinds of headaches including a dead piece of
equipment. Start with the +/-25 volt outputs are right and have no
ripple. I see no Germanium transistors listed. I see are bipolar
silicon, and a few FET. The parts list is in the middle of the manual,
the manual is dated 1973, and has a lot of design changes in the back
and sorted by serial number groups. Unless you are very familiar with
troubleshooting, you may need help.

[Robert Baer]

I did NOT say that; i mentioned where the problem was most likely to
be found.
Yes, it is possible that there may be one or two degraded
'lytics..even the old wet electrolytics lasted 20 years at best and even
then many could be recovered by adding electrolyte.
On old tube equipment, powering them up with a variac at zero and s l
o w l y raising the line voltage to full will allow most of degraded
'lytics to re-form and perform adequately at worst.

[rickman]

Ok, I'll bite, who is Maynard Philbrick? I thought the name was
familiar, but googling it doesn't provide anything useful, mainly
genealogy pages. I can't even seem to exclude them they are so
pervasive. Linking the name to HP doesn't do it either.

The name does sound familiar. Is that a name here?

> HP used germanium transistors in the '60s designs, like everyone
> else, then moved to silicon. They weren't penny pinching, they were
> cutting edge designs.
>
> You should always verify the power supply is in spec on test
> equipment before doing anything else. Slight errors are compounded, and
> can cause you all kinds of headaches including a dead piece of
> equipment. Start with the +/-25 volt outputs are right and have no
> ripple. I see no Germanium transistors listed. I see are bipolar
> silicon, and a few FET. The parts list is in the middle of the manual,
> the manual is dated 1973, and has a lot of design changes in the back
> and sorted by serial number groups. Unless you are very familiar with
> troubleshooting, you may need help.

I've mainly worked on digital stuff including state of the art (at the
time of course) floating point array processors. Analog is not my
forte, but I'm comfortable with it.

It seems I am spending more time getting a new lab setup than actually
working on anything. I cleared out some old appliances and now have
room for an 8 foot workbench which I plan to build. But before I do
that I am turning my hand router and hand saw into table tools to help
with the workbench construction. The test gear is the same way, I need
this to fix that and before I can use that I need this other thing...
I've let things slide too long.

Wasn't it Lincoln who said, "Give me six hours to chop down a tree and I
will spend the first four sharpening the axe"?

I'd prefer to use a chain saw...

Rick

[Michael A. Terrell]

rickman wrote:
>
> On 1/27/2013 11:03 PM, Michael A. Terrell wrote:
> >
> > rickman wrote:
> >>
> >> On 1/27/2013 8:12 PM, Jamie wrote:
> >>> rickman wrote:
> >>>
> >>>> On 1/26/2013 6:48 PM, David& Cheryl Denslow wrote:
> >>>>
> >>>>> "Jamie"<jamie_ka1lpa_not_v...@charter.net> wrote in
> >>>>> message
> >>>>> news:tnZMs.134394$pV4....@newsfe21.iad...
> >>>>>
> >>>>>>
> >>>>>>
> >>>>>> Caps..and power supply.

> ??????
> ?????? Jamie
> ??????
> ?????
> ????? Operator and Service Manual for P 3310A/B is available here:
> ????? http://cp.literature.agilent.com/litweb/pdf/03310-90003.pdf
> ?????
> ?????
> ????
> ???? Thanks. I'll take a look at it. I guess I'm just intimidated by the
> ???? disassembly job alone.
> ????
> ???? It doesn't really look like a PSU issue to me. I would suspect the
> ???? switches, but when I work them it just doesn't feel like that's the
> ???? problem. The unit has tons of test points so that should make it
> ???? easier to see what is going on.
> ????
> ???? Rick
> ??? I am not sure the age of that unit but I hope it's newer than the tube
> ??? era :) A LCR meter would serve you will, along with a DMM.
> ???
> ??? Oh, and lets us not for get to use a scope on the power supply for cap
> ??? ripples and possible linkage in selenium devices and maybe germanium.
> ???
> ??? Jamie
> ??
> ?? Thanks for the suggestions, after several folks have said to check power
> ?? I guess I'd better do that. But what's with the selenium and germanium
> ?? devices? This thing wasn't built in the 50's I'm pretty sure. What do
> ?? you mean about "linkage"? Do you mean leakage?
> ?
> ?

> ? Listen to Maynard Philbrick at your own risk.
>
> Ok, I'll bite, who is Maynard Philbrick? I thought the name was
> familiar, but googling it doesn't provide anything useful, mainly
> genealogy pages. I can't even seem to exclude them they are so
> pervasive. Linking the name to HP doesn't do it either.
>
> The name does sound familiar. Is that a name here?

That is 'Jamie's real name.

> ? HP used germanium transistors in the '60s designs, like everyone

> ? else, then moved to silicon. They weren't penny pinching, they were
> ? cutting edge designs.
> ?
> ? You should always verify the power supply is in spec on test
> ? equipment before doing anything else. Slight errors are compounded, and
> ? can cause you all kinds of headaches including a dead piece of
> ? equipment. Start with the +/-25 volt outputs are right and have no
> ? ripple. I see no Germanium transistors listed. I see are bipolar
> ? silicon, and a few FET. The parts list is in the middle of the manual,
> ? the manual is dated 1973, and has a lot of design changes in the back
> ? and sorted by serial number groups. Unless you are very familiar with
> ? troubleshooting, you may need help.

>
> I've mainly worked on digital stuff including state of the art (at the
> time of course) floating point array processors. Analog is not my
> forte, but I'm comfortable with it.

Just remeber to check all the 'Backdates' at the rear of the manual
if you find something that doesn't match the schematic or parts lists.
Some HP semiconductors have replacements available from www.nteinc.com

> It seems I am spending more time getting a new lab setup than actually
> working on anything. I cleared out some old appliances and now have
> room for an 8 foot workbench which I plan to build. But before I do
> that I am turning my hand router and hand saw into table tools to help
> with the workbench construction. The test gear is the same way, I need
> this to fix that and before I can use that I need this other thing...
> I've let things slide too long.
>
> Wasn't it Lincoln who said, "Give me six hours to chop down a tree and I
> will spend the first four sharpening the axe"?

You can make a good ax in four hours. You can sharpen a good ax in
15 minutes.

> I'd prefer to use a chain saw...

I need a front end loader, after my shop roof was damaged. I've been
using a coal shovel to scoop up service manuals destroyed by water.
Next will be a rake, folled by a scraper & a push broom to clean uo the
debris where termites ate into the damp paper. There were a bunch of
new boxes of greenbar paper destroyed, as well.

[tm]

"Robert Baer" <rober...@localnet.com> wrote in message

news:zzzNs.2337$Sq4....@newsfe14.iad...

OK then. Sorry for the comment. I miss-understood what you were implying.
And agree with your assessment.

[tm]

"rickman" <gnu...@gmail.com> wrote in message

news:ke70ge$6vh$1...@dont-email.me...

Hey, I like all that old HP, Tektronix, Fluke, Boonton, etc. equipment. It
is still serviceable, unlike all the new stuff. And pennies on the pound.
Although it's lots of pounds.

[rickman]

On 1/28/2013 6:28 PM, tm wrote:
>
> OK then. Sorry for the comment. I miss-understood what you were implying.
> And agree with your assessment.

I'm sorry tm, with an attitude like that, you won't be allowed to
continue posting in this group. You need to get an attitude to hang
here. Oh yeah, you need to never trim any posts too! lol

Rick

[rickman]

I didn't realize he was being literal. But then maybe part of that was
getting the grinding wheel in really good condition. lol

>> I'd prefer to use a chain saw...
>
>
> I need a front end loader, after my shop roof was damaged. I've been
> using a coal shovel to scoop up service manuals destroyed by water.

> Next will be a rake, folled by a scraper& a push broom to clean uo the

> debris where termites ate into the damp paper. There were a bunch of
> new boxes of greenbar paper destroyed, as well.

That has got to suck! Not as bad as a fire though. With those you get
fire, smoke *and* water damage, the tri-fecta! I saw a web page once
where a guy had a terminal (it was a long time ago) start a fire. He
had all sorts of problems and gave a lot of good info on how to protect
things. Mostly it was about preventing smoke and water damage.

Rick

[rickman]

I have to admit I haven't had time to look at the schematic of this
unit, but the more I think about it, the less I think it would be the
diode function generator (DFG). That just turns the triangle wave into
a sine, right? This fault reverses the direction of the sine wave in
mid course and changes the frequency as a consequence.

But then I am not that familiar with the operation of the DFG in any
detail. If the triangle wave were to change and not go as far negative
as it should, that would produce the waveform I am describing, right?
In fact, you could consider this to be a sine wave that is clipped in
time rather than amplitude. It has a phase section clipped out of it,
maybe 210° to 330°. Without disturbing the circuit at all, the point of
clipping changes on its own a bit too. So a freq counter won't give a
stable display. I guess I should look into the time base circuit...
after checking all the supply voltages of course.

--

Rick

[josephkk]

How about posting a scope trace of the wonky waveform in abse? or some
picture hosting site?

?-)

[rickman]

Sorry this took me a while. Here is a drawing of what I see. Not
exactly like the oscope display, but shows the important stuff.

http://arius.com/stuff/HP3310B/HP3310B_malfunction.png

Note that when set for 50 kHz, the measured frequency varies around 80
kHz.

--

Rick

[George Herold]

> Rick- Hide quoted text -
>
> - Show quoted text -

Weird, I understand this is a basically analog device (Not a DDS).
Then it looks like some inverter falling out of the signal chain.
Intermitent power to some section.... maybe? Does it change if you
load down the output? Have you opened it up and wiggled things?

George H.

[rickman]

No, I haven't loaded the output. I have probed and prodded with my
fingers. I think there was a point where it had some impact. I just
haven't taken the time to look at the docs yet. I'm thinking the ramp
generator is messing up and triggering the switch to the up ramp too soon.

--

Rick

[tm]

"rickman" <gnu...@gmail.com> wrote in message

news:kf1jev$3ml$1...@dont-email.me...

What were your measured power supply voltages? Ripple?

+25 = ?
-25 = ?
+10 = ?
-10 = ?

[rickman]

I didn't write them all down, but they are all within 0.2 volts of
nominal and I don't see any ripple on the supplies.

On the other hand, the fact that the problem is only on the two upper
ranges indicates it is within the "High Frequency Level Detector". I
measured some voltages there and the lower half seems to be way out of
whack. There are two symmetrical circuits to generate what would seem
to be a reference voltage for the +-5 volt level detector. But I'm not
sure that is how it works really. According to the schematic notes,
changing the switch from the lower ranges to the two higher ranges
changes the "references" from +10 / -10 volts to -10.6 / +10.6 volts.
What?

Something else I don't get is one transistor in each half is reverse
biased, yes, the CB junction is reverse biased, but the BE junction is
also reverse biased by 6 volts! The emitter resistor is connected to
+10 volts, the collector is connected to -10 volts and the emitter is
supposed to be at +10.6 volts! What??? The transistor is a PNP and the
base is supposed to be at +16.8 volts. How is this supposed to work?
Have I forgotten my transistor notation? PNP is arrow pointing to base
which should be more negative than the emitter, right?

Anyway, the half that is whacked out has some random fluctuations that I
can see on the scope which don't appear on the supplies. I figure one
of the components is bad but I can't trace it to anything in particular.
The circuit all interacts somewhat and the "noise" signal appears
through nearly all of it.

Parts of the large schematic pages are missing. I assume somewhere they
tell you the conditions for taking the measurements, but I haven't found
them yet. They do have a troubleshooting section that clearly tells you
to look in this circuit.

--

Rick

[tm]

"rickman" <gnu...@gmail.com> wrote in message

news:khj0oj$c3h$1...@dont-email.me...

All the conditions for the measurements are on PDF page 71, schematic 2, at
the lower right side of the page. Look for all the waveforms just to the
right of the notes section.

What you describe cries out leaky capacitor. Since it is only doing it on
the upper two ranges, that sure points to that circuit.

All of the transistors in that circuit are 2N3904 (N) or 3906 (P) so a
shotgun approach might be worth it in case it is a leaky transistor.

Take note of Note-5.

[rickman]

Thanks. My copy doesn't have complete pages of the schematics. They
are cut off at the bottom and when they span two pages there is a gap in
the middle. I think I got this from the Agilent site. Is there a
better copy available somewhere else?

BTW, to make it more viewable I rearranged the schematics a bit and
rotated the vertical pages. I see notes on page 70 of 87 and this page
also has assemblies A2 and A3 and waveforms 12 through 16. Is this the
page you mean?

It includes notes 1 through 3 which is cut off a bit. I don't have
notes 4 and 5 at all. On my page 68 I see notes, but all of the data on
the right is cut off and note 5 is missing.

Wait! I found an intact set of notes on page 77. I will recheck the DC
measurements with the settings indicated. This may bring the good
section into alignment with the schematic values, but I'm sure the bad
half will still be bad. Problem is I just don't know how transistors
are expected to behave when both junctions are reverse biased like the
schematic says they should be.

I think your shotgunning idea is good, I just don't relish the idea of
taking this thing apart, but I guess it can't be too bad. When they
have front panel switches soldered to the board it makes me twinge. I'm
probably just being overly worried, I expect it is made to be repaired
as well as assembled, unlike today's stuff.

Heck, I might want to get a second one so I can use it to make a sweep
generator!

--

Rick

[Robert Baer]

See my posting "Re: HP 3310B Malfunction Generator" in a.b.s.electronic.

[DaveC]

Join the Yahoo group for HP Test Equipment. LOTS of engrs and techs have tons
of experience with the "boat anchor" HP's. I'm sure more than one has been
down this road with your particular gen.

http://groups.yahoo.com/group/hp_agilent_equipment

Good luck.

Dave

[Michael A. Terrell]

rickman wrote:
>
>
> Thanks. My copy doesn't have complete pages of the schematics.

Print all the partial schematics and try piecing them together.

[rickman]

That won't generate the missing pieces. In my copy of the manual from
Agilent the schematics are not complete.

--

Rick

[rickman]

Great idea, thanks!

--

Rick

[rickman]

I don't seem to have access to binary groups. My server doesn't host
them and Google Groups doesn't seem to support them either.

Thanks for the effort.

--

Rick

[tm]

"rickman" <gnu...@gmail.com> wrote in message

news:kho3l8$sv1$1...@dont-email.me...

Look here:

http://www.ko4bb.com/manuals/index.php?dir=HP_Agilent

About 1/2 way down the page.

[rickman]

Hi tm,

I was just going to post thanking DaveC for pointing me to the yahoo
group where I found info pointing me to this link. It is downloading as
I type. It is a slightly older copy, but it is much better quality and
larger, 72 MB vs. 5 MB!

Thanks for the advice. This site is a treasure trove. I will feel much
better about buying old equipment on eBay. In fact, I may work on my
oscope to see if I can get the second channel working again. I wish I
could find a source for the horizontal position pot. It has been
terribly dirty for years. I asked HP about it once and they wanted $50
for a replacement, but that was way back when I could barely afford the
scope, much less money for expensive repairs. I think I wouldn't pay
$50 now, but only because the scope is barely worth that I think.

I'll say one thing about this unit, it is a field service model with a
vertically oriented front panel. So it takes up much less space on the
workbench than the horizontal units. Why don't they use this profile
with *all* the scopes? The screen fits nicely above most of the
controls and inputs with a small panel of buttons beside the screen
(power, brightness, etc.). With today's scopes they are very thin, but
still are wide horizontally. Why not thin and taller? I guess they
might be more tipsy... Makes me want to build my own.

--

Rick

[rickman]

On 3/12/2013 1:36 PM, DaveC wrote:

Dave,

Thanks a lot for this link. I found some discussions on this unit and
one pointed me to a more complete manual! Great suggestion!!!

Now I just need to figure the durn thing out. One of the posts I read
seems to be saying that the voltages in the manual require some mods to
the circuit and I see what they mean. Voltages on the output are -16V
when the output, as we know, should be 0 volts. I may be seeing
something similar on the high frequency circuit.

--

Rick

[DaveC]

> Thanks a lot for this link. I found some discussions on this unit and
> one pointed me to a more complete manual! Great suggestion!!!
>
> Now I just need to figure the durn thing out. One of the posts I read
> seems to be saying that the voltages in the manual require some mods to
> the circuit and I see what they mean. Voltages on the output are -16V
> when the output, as we know, should be 0 volts. I may be seeing
> something similar on the high frequency circuit.

Glad to turn on someone else to a great resource.

It looks like you're off and running!

Good luck.

Cheers,
Dave

[Robert Baer]

OK; go to: http://www.oil4lessllc.org/HP3312A/

[rickman]

Ok, I can get to that one. But what is it for? That is not the same
unit at all. It looks like a much more modern unit with wide use of op
amps rather than a bazillion transistors? I guess it might be a better
unit to buy?

--

Rick

[Robert Baer]

Yes, i figured that the design was different even tho the function
seemed to be the same.
Been awhile since i looked at the incomplete Agilent schematic, but
the diode array and biasing should be the same.
In this schematic, except for Q306 and Q309, all transistors are
fully active (no reversed biased E-B or forward biased B-C junctions).
Maybe i should look at their crummy schematic..

..still looking at it; will respond later.

[Robert Baer]

Robert Baer wrote:
> rickman wrote:
>> On 3/13/2013 4:00 PM, Robert Baer wrote:

*********** BIG SNIP

>>>>> See my posting "Re: HP 3310B Malfunction Generator" in
>>>>> a.b.s.electronic.
>>>>
>>>> I don't seem to have access to binary groups. My server doesn't host
>>>> them and Google Groups doesn't seem to support them either.
>>>>
>>>> Thanks for the effort.
>>>>
>>> OK; go to: http://www.oil4lessllc.org/HP3312A/
>>
>> Ok, I can get to that one. But what is it for? That is not the same unit
>> at all. It looks like a much more modern unit with wide use of op amps
>> rather than a bazillion transistors? I guess it might be a better unit
>> to buy?
>>
> Yes, i figured that the design was different even tho the function
> seemed to be the same.
> Been awhile since i looked at the incomplete Agilent schematic, but the
> diode array and biasing should be the same.
> In this schematic, except for Q306 and Q309, all transistors are fully
> active (no reversed biased E-B or forward biased B-C junctions).
> Maybe i should look at their crummy schematic..
>
> ..still looking at it; will respond later.
>
>

See Agilent PDF page 71 TP5 is equivalent to junction on mine
described by CR322, CR321, R353, R351 and R350. Likewise, TP7 is
equivalent to junction on mine described by CR323, CR319, R352, R346 and
R344.
Lastly, the "center", (sinewave) of TP6 is my TP13.

Now on mine, it is mostly obvious that the incoming triangle wave via
R369 (from output of op amp U301) is/must be symmetrical about ground
and (going from left to right) each pair of diodes will "clip" that
waveform at a level set by their common resistor at the output line
TP13; each clipping point being more severe (lower common R value) and
at a higher level (further away from ground).
Finally, the peak is clipped at the top, set by R348 and R342.

On the Agilent, PDF page 18, note there is NO "high frequency" monkey
business WRT the sine forming, as i seem to have seen mentioned. Ditto
with mine. Exception may be small trim caps or such.
TP6 appears to be at ground with the waveform symmetrical, just like
mine.
So...at "low" frequencies (10-1000 cps) the triangle coming from the
triangle amp (Pg 18 again) better the hell be EXACTLY symmetrical and
well behaved.
And it should stay that way all the way to the high end on the top range.
I think that may be the key, and so there may be more than one
problem - the first being this triangle waveform ain't not nowhere near
symmetrical (to use bad Engrish).

TP5 should be as negative as TP7 is positive; i derived that from the
necessary biasing for that DFG, and the schematic voltages noted confirm
that.
Resistor and voltage values from one to the other in the DFG will be
different, but more-or-less on a ratio basis, they should track.

Once you get the triangle symmetrical, then it should be fairly easy
to find a bad resistor or diode in the DFG (am guessing this as being a
secondary problem).
Maybe one of the stared capacitors in the sine shaper amplifier is
bad, but i doubt it; if there is a problem there HF-wise, it would be
due to a transistor (Q2 or Q3).

[rickman]

On 3/14/2013 5:55 AM, Robert Baer wrote:

Yes, that is exactly the problem. The triangle is not symmetrical. The
high speed circuit is not about clipping the triangle into a sine wave,
it "adjusts" the circuit that detects the triangle has reached +-5 volts
and reverses the direction of the waveform. The -5 volt detect seems to
work ok on the lower ranges. On the 10k and 100k ranges the high speed
circuit kicks in to modify the operation of the +-5 volt detect circuit
so that it triggers just early enough to give a proper +-5 volt triangle
in spite of whatever delays it has. This is when it malfunctions and
looks like it is not going far enough negative, which is confirmed on
the scope. The trigger level seems to vary erratically which is also
seen on the internal test points.

The symptom is clearly a malfunction of the high speed circuit, plus, I
can see erratic drift of the DC values both on the meter and with the
scope. The drift is small, but the DC values are also wrong on the -5
volt half of this circuit. I just can't pin any of this down since I'm
not clear on how the circuit works. The parts I understand will all
affect each other if any of them malfunction.

> TP5 should be as negative as TP7 is positive; i derived that from the
> necessary biasing for that DFG, and the schematic voltages noted confirm
> that.
> Resistor and voltage values from one to the other in the DFG will be
> different, but more-or-less on a ratio basis, they should track.
>
> Once you get the triangle symmetrical, then it should be fairly easy to
> find a bad resistor or diode in the DFG (am guessing this as being a
> secondary problem).
> Maybe one of the stared capacitors in the sine shaper amplifier is bad,
> but i doubt it; if there is a problem there HF-wise, it would be due to
> a transistor (Q2 or Q3).

I'm not worried about the DFG actually, I'm confident the problem is in
the high speed circuit. I just can't figure out which part is bad.
Someone suggested the caps often fail, at least the electrolytics
anyway. There is one cap that looks like an electrolytic, but the
schematic says it is 0.1 uF and the parts list says it is a 1.0 uF part.
I'm starting to loose confidence in HP docs. I may have to shotgun
it... or just use it on the lower ranges only.

--

Rick

[josephkk]

May i presume that you are using this document for the schematic?:

http://cp.literature.agilent.com/litweb/pdf/03310-90003.pdf

So that we can all be on the same pages.

?-)

[tm]

"josephkk" <joseph_...@sbcglobal.net> wrote in message
news:gr45k8dlrdb3kabpb...@4ax.com...

+++++++++++++++++++++++++++++++++++


http://ko4bb.com/Manuals/HP_Agilent/HP_3310AB_OS.pdf


This is a better copy.

[Robert Baer]

Yes, better, but still a lot missing.
At least, see page 76 there for a complete DFG schematic, and pages
79 & 80 for a complete A3 (order is srdawkcab).

HF problems aside, fix the triangle FIRST and make it as perfect as
possible.

[rickman]

That schematic has missing info. I found a better copy at KO4BB.com and
edited the pages a bit to make it easier to view.

HP_3310AB_OS_1971_edited.pdf

--

Rick

[rickman]

On 3/15/2013 1:39 AM, Robert Baer wrote:

> tm wrote:
>>
>> May i presume that you are using this document for the schematic?:
>>
>> http://cp.literature.agilent.com/litweb/pdf/03310-90003.pdf
>>
>> So that we can all be on the same pages.
>>
>> ?-)
>>
>> +++++++++++++++++++++++++++++++++++
>>
>>
>> http://ko4bb.com/Manuals/HP_Agilent/HP_3310AB_OS.pdf
>>
>>
>> This is a better copy.
>>
>>
> Yes, better, but still a lot missing.
> At least, see page 76 there for a complete DFG schematic, and pages 79 &
> 80 for a complete A3 (order is srdawkcab).
>
> HF problems aside, fix the triangle FIRST and make it as perfect as
> possible.

The HF circuit is the *cause* of the triangle problems. The triangle is
just a constant current into a cap. When it reaches +5 volts the detect
circuit switches the current source to ramp down to -5 volts, then the
cycle repeats. The HF circuit modifies the threshold of the +-5 volt
detect circuit which is part of forming the triangle wave. The problem
is the -5 volt detect is happening too soon and the triangle is not
going far enough negative. The *only* happens when switched to the 10k
or 100k ranges. The only difference in the ranges is that the HF
circuit is kicked in (and the value of the integrating cap, but they are
different between the 10k and 100k ranges).

Just to be clear, the triangle still looks just like a triangle. The
symptoms are:

1) doesn't go negative enough,
2) faster than it should be,
3) frequency is erratic,
4) sine wave is truncated on the negative half

To me, this clearly points to the HF circuit. The wave shaper only
affects the sine wave and won't change the frequency. The sine wave is
affected because the triangle doesn't go negative enough.

--

Rick

[Jamie]

Good site, thats.. Put that in my Book marks.

Jamie

[rickman]

On 3/15/2013 9:46 PM, Jamie wrote:

> rickman wrote:
>
>> That schematic has missing info. I found a better copy at KO4BB.com
>> and edited the pages a bit to make it easier to view.
>>
>> HP_3310AB_OS_1971_edited.pdf
>>
> Good site, thats.. Put that in my Book marks.
>
> Jamie

Yeah, I thought it was pretty impressive too. BTW, are you British?
That sounds like a British expression to me... "Good site, that". Or
maybe an Aussie?

--

Rick

[Jamie]

My grand father was British born (Holmes), but I was born in Maine
where every one is related. THe tree does not branch out too far!!!!!!!!!!

Some one told me the other day they don't bother to do crime
investigations with DNA in Maine any more, the results are always
inconclusive.

Jamie

[rickman]

LOL!

--

Rick

[Robert Baer]

Well, then work on the negative threshold sense circuit as well as
its "compensation": threshold first at low frequencies for symmetry and
then the comp.