Re: HP 419A DC Null Voltmeter - INSANE behaviour
Hope this thread is not totally dead. The 3x switch strange behavior with oscillations at TP1 of A4 happened to me. I have two 13.2v hand tool nicads to power my 419.? I had wired in the +13 and -13 battery leads into the instrument,? I failed to connect the neutral wire between the batteries into the instrument power ground (eg. the case). With that wire added, the 3x insane behavior was gone.??
|
My dsylixa got in the way.? The boards are from a 8640b
On Wed, Apr 1, 2020, 8:35 PM n4buq < n4buq@...> wrote: Hi, John,
Just curious: Are those for an 8604B or an 8640B?? I don't know whether there's an 8604B but maybe?
Thanks,
Barry - N4BUQ
----- Original Message -----
> From: "John Corini" <john.corini@...>
> To: [email protected]
> Sent: Wednesday, April 1, 2020 6:45:13 PM
> Subject: [HP-Agilent-Keysight-equipment] HP 8604B parts FS
>
> Hi,
>
> I have a number of PCBs that are available from a non-functional 8604B.
> The boards are 10:00 plus shipping:
>
> 0860-60326
> 0860-60351
> 0860-60014
> 0860-60004
> 0860-60177
> 0860-60005
> 0860-60304
> 0860-60029
>
> Again, I have no idea if these are functional or not.
>
> Regards,
>
> John
> KE1IH@...
>
>
>
>
|
Phase Locking an 8350 Plugin
Hi Group! Has anyone tried doing this? I am going to try it but the manual for the 83590A (2-20 GHZ) is a bit confusing.  I found/bought the 8709A (unknown condition - might be a new topic!) and a 934A mixer. The Sig Gen (8640A, Opt 002) runs up to 1024 MHz. But the 8709A compares to 20 MHz so the Sig Gen I think needs to be much higher than 1024 MHz! What am I missing here? The next part of the manual:  A bit hard to read but it says for Fo less than 2.0 GHz??? That's outside the range of this plugin, so makes no sense. At any rate, gonna play with this. My RF gen only goes to 1024 MHz so can't go to say 10GHz - 20MHz. Hmm. Thoughts appreciated. Mark
|
Hi, John,
Just curious: Are those for an 8604B or an 8640B? I don't know whether there's an 8604B but maybe?
Thanks,
Barry - N4BUQ
toggle quoted message
Show quoted text
----- Original Message ----- From: "John Corini" <john.corini@...>
To: [email protected]
Sent: Wednesday, April 1, 2020 6:45:13 PM
Subject: [HP-Agilent-Keysight-equipment] HP 8604B parts FS
Hi,
I have a number of PCBs that are available from a non-functional 8604B.
The boards are 10:00 plus shipping:
0860-60326
0860-60351
0860-60014
0860-60004
0860-60177
0860-60005
0860-60304
0860-60029
Again, I have no idea if these are functional or not.
Regards,
John
KE1IH@...
|
Harvey, my main problem is identifying the various parts.? The manual isn't the easiest for me.? Perhaps you can walk me around to the various places where I can make measurements.? I certainly have no shortage of sources of dc or ac of any reasonable frequency and amplitude.
I did measure the 10V reference with my 3456A at 10.00007 I think.? (not sure how many zeros)? So what we have here are all the pieces of a good meter if I can make it play.
Bob
On Wednesday, April 1, 2020, 05:09:17 PM PDT, Harvey White <madyn@...> wrote:
If I might:
generally, a signal goes through attenuators, then? is converted
to digital.? This is done in a floating processing environment
called (by HP) the inguard processor.? That is optically coupled
to an "outguard" processor, which is the main processor driving
the display.? Any break in the chain can result in zeros.?
Firstly, I'd take the signal from the inputs, then see how far it
gets.? If you can see anything changing in the digitally coupled
outputs (optically isolated), might be working.? You'll need to
check on both ends of the optical isolators.? That's assuming they
have them.? The 3456 has two very isolated transformers that need
to be checked.? What I found is that one of the processors itself
was dead when I was trying to resurrect some of them.
So the bottom line is to try to follow the signal.? An AC signal
would be easiest but you'd have to tell it that it's really DC,
otherwise you to the AC converter.? If you should try to do an AC
signal into the DC input, what you're looking for is the presence
or absence of a signal (to a point where the circuitry gets
confused and/or ignores it) and after that, the signal isn't
there.? At that point, you need to match the AC signal to an AC
input, or DC to DC.
This is based on my experiences with a 3456, so YMMV
Harvey
On 4/1/2020 1:36 PM, Bob Albert via
groups.io wrote:
Well Chuck, I don't know what
to do next with this beast.? It acts as though it works but
the display gives nothing useful.? Yet the display electronics
seem to be working okay.
If I put a signal in, it
ignores it.? Open or short on Ohms, voltage or no on volts,
gives zeros and no autorange activity.? So perhaps it's an
input circuit issue.? In Test I get error 11.? I press test
repeatedly and it gives error numbers 10, 9, etc down to 0.
The manual sucks.? It tells
me to look on module such and such but nowhere does it seem to
show me which module is where.
Bob
On Wednesday, April 1, 2020, 10:22:56 AM PDT, Chuck
Harris <cfharris@...> wrote:
Hi Bob,
I don't see how you can come to that conclusion.
The 3455A is highly reparable, and should be well
within your abilities.? Lots of people have fixed
their own successfully.
What you won't be able to do is send its calibration
module out for calibration.? You will have to do that
yourself.? But, it is not any more difficult to
calibrate than the 3456A.
It is not my meter of choice, as I greatly prefer
the 3456A, but for many, it is a useful addition to
their labs.
-Chuck Harris
Bob Albert via groups.io wrote:
>? I don't see a whole lot of encouragement here
regarding the possibility of getting my 3455A working.?
Maybe I will just put it aside and wait for a scrap unit
to swap out boards or parts.? My 3456A still works so I am
grateful for that.
> Bob
>? ? On Wednesday, April 1, 2020, 06:40:17 AM PDT,
Chuck Harris < cfharris@...>
wrote:
>
>? The 3455A was a dinosaur when it was first released.
>
> The 3455A and 3456A were sold side by side, with the
> 3455A being about twice as expensive as the much more
> capable 3456A.? The 3455A's interesting feature was
> it was supposed to be cheap to calibrate.? All you
> had to do to do a complete calibration was to unplug
> the module in the back panel, and replace it with a
> recently calibrated module.? The idea was you could
> order up a calibration by mail, and return your old
> calibration module as a core... never having to send
> the full meter in for calibration.
>
> Interesting idea, but surely not worth twice the
price
> of a 3456A.
>
> I say it was a dinosaur, because it used all small
> scale logic rather than large highly capable hybrid
> circuitry, like the 3456A.? It should be much easier
> to repair, but it should also be much less reliable.
>
> And, that is my experience with the two units.
>
> -Chuck Harris
>
> paul swedberg wrote:
>> With respect to the 3455 and 3456 the difference
is night and day. I have
>> numbers of 3456s and was given a seriously
troubled 3455. Quite a
>> interesting meter.
>> Replaced at least 11 actually malfunctioning
chips on the logic board. The
>> logics simple so easy to verify the chips were
bad. No shot gunning
>> involved. Never really did get it working but
ended up with a different
>> 3455 that needed help and the AC board and it is
in fine shape. With
>> respect to the old 3455 it has both a logic and
voltmeter issue. The 3455
>> uses an unusual processor and teh DVM uses the
same proc and a masked eprom
>> that is known to go bad. It acts as a state
machine.
>> The 3456s are losing there eproms and copies can
be found on the net. Thank
>> heavens.
>> Regards
>> Paul
>> WB8TSL
>>
>>
>>
>>
>
>
>
>
>
>
>
>
|
If I might:
generally, a signal goes through attenuators, then? is converted
to digital.? This is done in a floating processing environment
called (by HP) the inguard processor.? That is optically coupled
to an "outguard" processor, which is the main processor driving
the display.? Any break in the chain can result in zeros.?
Firstly, I'd take the signal from the inputs, then see how far it
gets.? If you can see anything changing in the digitally coupled
outputs (optically isolated), might be working.? You'll need to
check on both ends of the optical isolators.? That's assuming they
have them.? The 3456 has two very isolated transformers that need
to be checked.? What I found is that one of the processors itself
was dead when I was trying to resurrect some of them.
So the bottom line is to try to follow the signal.? An AC signal
would be easiest but you'd have to tell it that it's really DC,
otherwise you to the AC converter.? If you should try to do an AC
signal into the DC input, what you're looking for is the presence
or absence of a signal (to a point where the circuitry gets
confused and/or ignores it) and after that, the signal isn't
there.? At that point, you need to match the AC signal to an AC
input, or DC to DC.
This is based on my experiences with a 3456, so YMMV
Harvey
On 4/1/2020 1:36 PM, Bob Albert via
groups.io wrote:
toggle quoted message
Show quoted text
Well Chuck, I don't know what
to do next with this beast.? It acts as though it works but
the display gives nothing useful.? Yet the display electronics
seem to be working okay.
If I put a signal in, it
ignores it.? Open or short on Ohms, voltage or no on volts,
gives zeros and no autorange activity.? So perhaps it's an
input circuit issue.? In Test I get error 11.? I press test
repeatedly and it gives error numbers 10, 9, etc down to 0.
The manual sucks.? It tells
me to look on module such and such but nowhere does it seem to
show me which module is where.
Bob
On Wednesday, April 1, 2020, 10:22:56 AM PDT, Chuck
Harris <cfharris@...> wrote:
Hi Bob,
I don't see how you can come to that conclusion.
The 3455A is highly reparable, and should be well
within your abilities.? Lots of people have fixed
their own successfully.
What you won't be able to do is send its calibration
module out for calibration.? You will have to do that
yourself.? But, it is not any more difficult to
calibrate than the 3456A.
It is not my meter of choice, as I greatly prefer
the 3456A, but for many, it is a useful addition to
their labs.
-Chuck Harris
Bob Albert via groups.io wrote:
>? I don't see a whole lot of encouragement here
regarding the possibility of getting my 3455A working.?
Maybe I will just put it aside and wait for a scrap unit
to swap out boards or parts.? My 3456A still works so I am
grateful for that.
> Bob
>? ? On Wednesday, April 1, 2020, 06:40:17 AM PDT,
Chuck Harris < cfharris@...>
wrote:
>
>? The 3455A was a dinosaur when it was first released.
>
> The 3455A and 3456A were sold side by side, with the
> 3455A being about twice as expensive as the much more
> capable 3456A.? The 3455A's interesting feature was
> it was supposed to be cheap to calibrate.? All you
> had to do to do a complete calibration was to unplug
> the module in the back panel, and replace it with a
> recently calibrated module.? The idea was you could
> order up a calibration by mail, and return your old
> calibration module as a core... never having to send
> the full meter in for calibration.
>
> Interesting idea, but surely not worth twice the
price
> of a 3456A.
>
> I say it was a dinosaur, because it used all small
> scale logic rather than large highly capable hybrid
> circuitry, like the 3456A.? It should be much easier
> to repair, but it should also be much less reliable.
>
> And, that is my experience with the two units.
>
> -Chuck Harris
>
> paul swedberg wrote:
>> With respect to the 3455 and 3456 the difference
is night and day. I have
>> numbers of 3456s and was given a seriously
troubled 3455. Quite a
>> interesting meter.
>> Replaced at least 11 actually malfunctioning
chips on the logic board. The
>> logics simple so easy to verify the chips were
bad. No shot gunning
>> involved. Never really did get it working but
ended up with a different
>> 3455 that needed help and the AC board and it is
in fine shape. With
>> respect to the old 3455 it has both a logic and
voltmeter issue. The 3455
>> uses an unusual processor and teh DVM uses the
same proc and a masked eprom
>> that is known to go bad. It acts as a state
machine.
>> The 3456s are losing there eproms and copies can
be found on the net. Thank
>> heavens.
>> Regards
>> Paul
>> WB8TSL
>>
>>
>>
>>
>
>
>
>
>
>
>
>
|
Hi,
I have a number of PCBs that are available?from a non-functional 8604B.? The boards are 10:00 plus shipping:
0860-60326 0860-60351 0860-60014 0860-60004 0860-60177 0860-60005 0860-60304 0860-60029
Again, I have no idea if these are functional or not.
Regards,
John KE1IH@...
|
Re: HP 3325A/B Option 002 HV output kit - who wants one?
Ok, I've got everyone who has posted or messaged me on the list now.
I'll put the current list up this weekend so you can all double check and correct me if I made any mistakes.
?
A little bad news though.... Due to the Corona virus, Japan Post has basically shut down all deliveries to 153 countries as of yesterday....
It ultimately won't stop me from completing this, but it will delay things for a while, and I have no idea how long.
?
I'll keep the updates coming, and if I can get the PCB's delivered (The major carriers like Fedex, DHL, UPS, etc are currently still delivering into Japan) then pictures and a few performance tests will be forthcoming too.
Anyway, orders will remain open until the last minute, so keep the list growing! I got 53 PCB's to order on the list so far (and a big portion of those are full kits, so I'll have a good amount of parts to sort through too!)
|
Re: Maximum depth of HP rack mountable gear?
A good point, especially for wooden floors.
No worries on my part though as I have a steel framed house with very strong floors. Being in Japan, the building is rated for the big earthquakes we get here so a rack is easy work for the structure. :)
toggle quoted message
Show quoted text
On Thu, Apr 2, 2020 at 05:52 AM, Matt Corbett wrote:
You guys already know this, but just in case: an important consideration in rack mounting your gear is the weight that the floor can support.? With some of the taller racks filled with equipment, you will have hundreds of kgs. of weight.? As an extreme (and fabricated) example, a common 7 foot (44U) rack could physically accommodate eleven HP8664A signal generators.? At 35kg each, these generators would weigh a total of 385 kg. (850 lbs.) -- and this doesn't including the weight of the rack itself, and any mounting accessories.? Be safe, everyone!
|
Re: Fixing a sick 4332A LCR meter
Hi Joel,
I will pick up the Artek version. Probably won't do any more work on it till the weekend, but to follow along with your thoughts:
- none of the ranges work. in R, the needle pegs HARD off scale high unless the leads are shorted. In C, it registers very low, and there's a lot of random needle movement, same for L.
- In C, there's a ~12 KHz ~20 mVpp sine present on some ranges, not present on others.
Sean
|
Re: Maximum depth of HP rack mountable gear?
You guys already know this, but just in case: an important consideration in rack mounting your gear is the weight that the floor can support.? With some of the taller racks filled with equipment, you will have hundreds of kgs. of weight.? As an extreme (and fabricated) example, a common 7 foot (44U) rack could physically accommodate eleven HP8664A signal generators.? At 35kg each, these generators would weigh a total of 385 kg. (850 lbs.) -- and this doesn't including the weight of the rack itself, and any mounting accessories.? Be safe, everyone!
|
Re: Maximum depth of HP rack mountable gear?
As already mentioned, the 8664A and 8665A/B signal generators have to be some of the deepest products that HP made.? This is especially true if you have an option -010 unit: the low rf leakage version.? They're heavy too, like a sack of cement!? Mine still have the yellow, "two person lift" safety labels attached to the cabinets.? Lots of good exercise in moving these beasts around.? Since purchasing the units, I was able to save money by canceling my gym membership! :-)
|
Re: Fixing a sick 4332A LCR meter
Hello again Sean,
Indeed, Artek has a good manual (actually, I was the one who lent them a paper copy for scanning).
The R36 burn may have occurred when someone accidentally fed an external voltage to the Guard terminal. This voltage would have been fed to R36 directly via the S1A(R) function switch. If this is what happened, obviously the cause of the burn is not within the meter, and replacing R36 will take care of this failure.
Then, of course, the real repair project starts ! I would think along these lines:
- First, are there any functions that DO work ? Try R, L, C, try several ranges, and see what happens.
- Since the power supplies are OK, the next step would be to check whether the oscillator and output amplifier are working. Set the function to Capacitance, and connect an oscilloscope at the HIGH input terminal. You should see a nice sine wave at 1 kHz or 100 kHz depending on range, with 77 mV RMS amplitude.
If you don't see this sinewave, then the problem is either in the oscillator (look at the emitter of A2Q2) or the low-Zout amplifier (A1 IC5).
If the sine wave on the HIGH output is OK, we'll continue the search in the measurement circuits. So, please let me know what you see... I'm more than happy to share the fun !!!
Sincerely,
Joel
|
Like most DVM's, there is a relay between the terminals on the
front panel, and the internal circuitry. If that relay is not
closing... for whatever reason... you would have behavior like
you are describing.
I have found lots of relay failures on the sorts of reed relays
that are used in the 3456 and 3455. I would suggest looking
there.
-Chuck Harris
Bob Albert via groups.io wrote:
toggle quoted message
Show quoted text
How do I know if the tests fail?? It just presents the test number and that changes each time I press TEST.
My level of hope has been raised.? I think this is repairable.? Yes, Inguard to Ourguard communication seems to be the clue.? When I put a signal in it does not change ranges.? The Auto range takes it to the lowest range every time, regardless.
Bob On Wednesday, April 1, 2020, 11:18:39 AM PDT, Orin Eman <orin.eman@...> wrote:
Figure 8-H-1 in my manual shows where the assemblies and test points are.
Do all the tests 11 down to 0 fail?
I'd do the cal constant tests (Section 8-B-11), monitoring A10 TP4 () to see if the right voltages are getting to the AtoD.? Table 8-B-5 has the voltages to look for.? The procedure is a little tricky, but you are looking to see if A10 TP4 gets different voltages as you step through the constants at this stage.
If these voltages look reasonable, I'd look at the inguard to outguard communication - there are test points on A3 in the outguard section.
On Wed, Apr 1, 2020 at 10:36 AM Bob Albert via groups.io <bob91343@...> wrote:
Well Chuck, I don't know what to do next with this beast.? It acts as though it works but the display gives nothing useful.? Yet the display electronics seem to be working okay.
If I put a signal in, it ignores it.? Open or short on Ohms, voltage or no on volts, gives zeros and no autorange activity.? So perhaps it's an input circuit issue.? In Test I get error 11.? I press test repeatedly and it gives error numbers 10, 9, etc down to 0.
The manual sucks.? It tells me to look on module such and such but nowhere does it seem to show me which module is where.
Bob
On Wednesday, April 1, 2020, 10:22:56 AM PDT, Chuck Harris <cfharris@...> wrote:
Hi Bob,
I don't see how you can come to that conclusion.
The 3455A is highly reparable, and should be well
within your abilities.? Lots of people have fixed
their own successfully.
What you won't be able to do is send its calibration
module out for calibration.? You will have to do that
yourself.? But, it is not any more difficult to
calibrate than the 3456A.
It is not my meter of choice, as I greatly prefer
the 3456A, but for many, it is a useful addition to
their labs.
-Chuck Harris
Bob Albert via groups.io wrote:
? I don't see a whole lot of encouragement here regarding the possibility of getting my 3455A working.? Maybe I will just put it aside and wait for a scrap unit to swap out boards or parts.? My 3456A still works so I am grateful for that.
Bob
? ? On Wednesday, April 1, 2020, 06:40:17 AM PDT, Chuck Harris <cfharris@...> wrote:
? The 3455A was a dinosaur when it was first released.
The 3455A and 3456A were sold side by side, with the
3455A being about twice as expensive as the much more
capable 3456A.? The 3455A's interesting feature was
it was supposed to be cheap to calibrate.? All you
had to do to do a complete calibration was to unplug
the module in the back panel, and replace it with a
recently calibrated module.? The idea was you could
order up a calibration by mail, and return your old
calibration module as a core... never having to send
the full meter in for calibration.
Interesting idea, but surely not worth twice the price
of a 3456A.
I say it was a dinosaur, because it used all small
scale logic rather than large highly capable hybrid
circuitry, like the 3456A.? It should be much easier
to repair, but it should also be much less reliable.
And, that is my experience with the two units.
-Chuck Harris
paul swedberg wrote:
With respect to the 3455 and 3456 the difference is night and day. I have
numbers of 3456s and was given a seriously troubled 3455. Quite a
interesting meter.
Replaced at least 11 actually malfunctioning chips on the logic board. The
logics simple so easy to verify the chips were bad. No shot gunning
involved. Never really did get it working but ended up with a different
3455 that needed help and the AC board and it is in fine shape. With
respect to the old 3455 it has both a logic and voltmeter issue. The 3455
uses an unusual processor and teh DVM uses the same proc and a masked eprom
that is known to go bad. It acts as a state machine.
The 3456s are losing there eproms and copies can be found on the net. Thank
heavens.
Regards
Paul
WB8TSL
|
Its been years since I've repaired one of these, but it sounds like the opto coupler may be a problem.
Quoting Orin Eman <orin.eman@...>:
toggle quoted message
Show quoted text
The test number is the test that failed. If you press test, it goes onto
the next test - so all the numbers it displays are failures.
It does sound like it's getting all zeros from the inguard. A10 TP4 will
tell if anything is getting close to the AtoD.
On Wed, Apr 1, 2020 at 11:34 AM Bob Albert via groups.io <bob91343=
[email protected]> wrote:
How do I know if the tests fail? It just presents the test number and
that changes each time I press TEST.
My level of hope has been raised. I think this is repairable. Yes,
Inguard to Ourguard communication seems to be the clue. When I put a
signal in it does not change ranges. The Auto range takes it to the lowest
range every time, regardless.
Bob
On Wednesday, April 1, 2020, 11:18:39 AM PDT, Orin Eman <
orin.eman@...> wrote:
Figure 8-H-1 in my manual shows where the assemblies and test points are.
Do all the tests 11 down to 0 fail?
I'd do the cal constant tests (Section 8-B-11), monitoring A10 TP4 () to
see if the right voltages are getting to the AtoD. Table 8-B-5 has the
voltages to look for. The procedure is a little tricky, but you are
looking to see if A10 TP4 gets different voltages as you step through the
constants at this stage.
If these voltages look reasonable, I'd look at the inguard to outguard
communication - there are test points on A3 in the outguard section.
On Wed, Apr 1, 2020 at 10:36 AM Bob Albert via groups.io <bob91343=
[email protected]> wrote:
Well Chuck, I don't know what to do next with this beast. It acts as
though it works but the display gives nothing useful. Yet the display
electronics seem to be working okay.
If I put a signal in, it ignores it. Open or short on Ohms, voltage or no
on volts, gives zeros and no autorange activity. So perhaps it's an input
circuit issue. In Test I get error 11. I press test repeatedly and it
gives error numbers 10, 9, etc down to 0.
The manual sucks. It tells me to look on module such and such but nowhere
does it seem to show me which module is where.
Bob
On Wednesday, April 1, 2020, 10:22:56 AM PDT, Chuck Harris <
cfharris@...> wrote:
Hi Bob,
I don't see how you can come to that conclusion.
The 3455A is highly reparable, and should be well
within your abilities. Lots of people have fixed
their own successfully.
What you won't be able to do is send its calibration
module out for calibration. You will have to do that
yourself. But, it is not any more difficult to
calibrate than the 3456A.
It is not my meter of choice, as I greatly prefer
the 3456A, but for many, it is a useful addition to
their labs.
-Chuck Harris
Bob Albert via groups.io wrote:
I don't see a whole lot of encouragement here regarding the possibility of getting my 3455A working. Maybe I will just put it aside and wait for a
scrap unit to swap out boards or parts. My 3456A still works so I am
grateful for that.
Bob
On Wednesday, April 1, 2020, 06:40:17 AM PDT, Chuck Harris < cfharris@...> wrote:
The 3455A was a dinosaur when it was first released.
The 3455A and 3456A were sold side by side, with the
3455A being about twice as expensive as the much more
capable 3456A. The 3455A's interesting feature was
it was supposed to be cheap to calibrate. All you
had to do to do a complete calibration was to unplug
the module in the back panel, and replace it with a
recently calibrated module. The idea was you could
order up a calibration by mail, and return your old
calibration module as a core... never having to send
the full meter in for calibration.
Interesting idea, but surely not worth twice the price
of a 3456A.
I say it was a dinosaur, because it used all small
scale logic rather than large highly capable hybrid
circuitry, like the 3456A. It should be much easier
to repair, but it should also be much less reliable.
And, that is my experience with the two units.
-Chuck Harris
paul swedberg wrote:
With respect to the 3455 and 3456 the difference is night and day. I
have
numbers of 3456s and was given a seriously troubled 3455. Quite a
interesting meter.
Replaced at least 11 actually malfunctioning chips on the logic board.
The
logics simple so easy to verify the chips were bad. No shot gunning
involved. Never really did get it working but ended up with a different
3455 that needed help and the AC board and it is in fine shape. With
respect to the old 3455 it has both a logic and voltmeter issue. The
3455
uses an unusual processor and teh DVM uses the same proc and a masked
eprom
that is known to go bad. It acts as a state machine.
The 3456s are losing there eproms and copies can be found on the net.
Thank
heavens.
Regards
Paul
WB8TSL
|
The test number is the test that failed.? If you press test, it goes onto the next test - so all the numbers it displays are failures.
It does sound like it's getting all zeros from the inguard.? A10 TP4 will tell if anything is getting close to the AtoD.
How do I know if the tests fail?? It just presents the test number and that changes each time I press TEST.
My level of hope has been raised.? I think this is repairable.? Yes, Inguard to Ourguard communication seems to be the clue.? When I put a signal in it does not change ranges.? The Auto range takes it to the lowest range every time, regardless.
Bob
On Wednesday, April 1, 2020, 11:18:39 AM PDT, Orin Eman < orin.eman@...> wrote:
Figure 8-H-1 in my manual shows where the assemblies and test points are.
Do all the tests 11 down to 0 fail?
I'd do the cal constant tests (Section 8-B-11), monitoring A10 TP4 () to see if the right voltages are getting to the AtoD.? Table 8-B-5 has the voltages to look for.? The procedure is a little tricky, but you are looking to see if A10 TP4 gets different voltages as you step through the constants at this stage.
If these voltages look reasonable, I'd look at the inguard to outguard communication - there are test points on A3 in the outguard section.
Well Chuck, I don't know what to do next with this beast.? It acts as though it works but the display gives nothing useful.? Yet the display electronics seem to be working okay.
If I put a signal in, it ignores it.? Open or short on Ohms, voltage or no on volts, gives zeros and no autorange activity.? So perhaps it's an input circuit issue.? In Test I get error 11.? I press test repeatedly and it gives error numbers 10, 9, etc down to 0.
The manual sucks.? It tells me to look on module such and such but nowhere does it seem to show me which module is where.
Bob
On Wednesday, April 1, 2020, 10:22:56 AM PDT, Chuck Harris < cfharris@...> wrote:
Hi Bob, I don't see how you can come to that conclusion. The 3455A is highly reparable, and should be well within your abilities.? Lots of people have fixed their own successfully. What you won't be able to do is send its calibration module out for calibration.? You will have to do that yourself.? But, it is not any more difficult to calibrate than the 3456A. It is not my meter of choice, as I greatly prefer the 3456A, but for many, it is a useful addition to their labs. -Chuck Harris Bob Albert via wrote: >? I don't see a whole lot of encouragement here regarding the possibility of getting my 3455A working.? Maybe I will just put it aside and wait for a scrap unit to swap out boards or parts.? My 3456A still works so I am grateful for that. > Bob >? ? On Wednesday, April 1, 2020, 06:40:17 AM PDT, Chuck Harris < cfharris@...> wrote: > >? The 3455A was a dinosaur when it was first released. > > The 3455A and 3456A were sold side by side, with the > 3455A being about twice as expensive as the much more > capable 3456A.? The 3455A's interesting feature was > it was supposed to be cheap to calibrate.? All you > had to do to do a complete calibration was to unplug > the module in the back panel, and replace it with a > recently calibrated module.? The idea was you could > order up a calibration by mail, and return your old > calibration module as a core... never having to send > the full meter in for calibration. > > Interesting idea, but surely not worth twice the price > of a 3456A. > > I say it was a dinosaur, because it used all small > scale logic rather than large highly capable hybrid > circuitry, like the 3456A.? It should be much easier > to repair, but it should also be much less reliable. > > And, that is my experience with the two units. > > -Chuck Harris > > paul swedberg wrote: >> With respect to the 3455 and 3456 the difference is night and day. I have >> numbers of 3456s and was given a seriously troubled 3455. Quite a >> interesting meter. >> Replaced at least 11 actually malfunctioning chips on the logic board. The >> logics simple so easy to verify the chips were bad. No shot gunning >> involved. Never really did get it working but ended up with a different >> 3455 that needed help and the AC board and it is in fine shape. With >> respect to the old 3455 it has both a logic and voltmeter issue. The 3455 >> uses an unusual processor and teh DVM uses the same proc and a masked eprom >> that is known to go bad. It acts as a state machine. >> The 3456s are losing there eproms and copies can be found on the net. Thank >> heavens. >> Regards >> Paul >> WB8TSL >> >> >> >> > > > > > > > >
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How do I know if the tests fail?? It just presents the test number and that changes each time I press TEST.
My level of hope has been raised.? I think this is repairable.? Yes, Inguard to Ourguard communication seems to be the clue.? When I put a signal in it does not change ranges.? The Auto range takes it to the lowest range every time, regardless.
Bob
On Wednesday, April 1, 2020, 11:18:39 AM PDT, Orin Eman <orin.eman@...> wrote:
Figure 8-H-1 in my manual shows where the assemblies and test points are.
Do all the tests 11 down to 0 fail?
I'd do the cal constant tests (Section 8-B-11), monitoring A10 TP4 () to see if the right voltages are getting to the AtoD.? Table 8-B-5 has the voltages to look for.? The procedure is a little tricky, but you are looking to see if A10 TP4 gets different voltages as you step through the constants at this stage.
If these voltages look reasonable, I'd look at the inguard to outguard communication - there are test points on A3 in the outguard section.
Well Chuck, I don't know what to do next with this beast.? It acts as though it works but the display gives nothing useful.? Yet the display electronics seem to be working okay.
If I put a signal in, it ignores it.? Open or short on Ohms, voltage or no on volts, gives zeros and no autorange activity.? So perhaps it's an input circuit issue.? In Test I get error 11.? I press test repeatedly and it gives error numbers 10, 9, etc down to 0.
The manual sucks.? It tells me to look on module such and such but nowhere does it seem to show me which module is where.
Bob
On Wednesday, April 1, 2020, 10:22:56 AM PDT, Chuck Harris < cfharris@...> wrote:
Hi Bob, I don't see how you can come to that conclusion. The 3455A is highly reparable, and should be well within your abilities.? Lots of people have fixed their own successfully. What you won't be able to do is send its calibration module out for calibration.? You will have to do that yourself.? But, it is not any more difficult to calibrate than the 3456A. It is not my meter of choice, as I greatly prefer the 3456A, but for many, it is a useful addition to their labs. -Chuck Harris Bob Albert via wrote: >? I don't see a whole lot of encouragement here regarding the possibility of getting my 3455A working.? Maybe I will just put it aside and wait for a scrap unit to swap out boards or parts.? My 3456A still works so I am grateful for that. > Bob >? ? On Wednesday, April 1, 2020, 06:40:17 AM PDT, Chuck Harris < cfharris@...> wrote: > >? The 3455A was a dinosaur when it was first released. > > The 3455A and 3456A were sold side by side, with the > 3455A being about twice as expensive as the much more > capable 3456A.? The 3455A's interesting feature was > it was supposed to be cheap to calibrate.? All you > had to do to do a complete calibration was to unplug > the module in the back panel, and replace it with a > recently calibrated module.? The idea was you could > order up a calibration by mail, and return your old > calibration module as a core... never having to send > the full meter in for calibration. > > Interesting idea, but surely not worth twice the price > of a 3456A. > > I say it was a dinosaur, because it used all small > scale logic rather than large highly capable hybrid > circuitry, like the 3456A.? It should be much easier > to repair, but it should also be much less reliable. > > And, that is my experience with the two units. > > -Chuck Harris > > paul swedberg wrote: >> With respect to the 3455 and 3456 the difference is night and day. I have >> numbers of 3456s and was given a seriously troubled 3455. Quite a >> interesting meter. >> Replaced at least 11 actually malfunctioning chips on the logic board. The >> logics simple so easy to verify the chips were bad. No shot gunning >> involved. Never really did get it working but ended up with a different >> 3455 that needed help and the AC board and it is in fine shape. With >> respect to the old 3455 it has both a logic and voltmeter issue. The 3455 >> uses an unusual processor and teh DVM uses the same proc and a masked eprom >> that is known to go bad. It acts as a state machine. >> The 3456s are losing there eproms and copies can be found on the net. Thank >> heavens. >> Regards >> Paul >> WB8TSL >> >> >> >> > > > > > > > >
|
Hello, Glenn--
You wrote...
"Has anyone seen abnormalities at 60, 120
and 180 Hz sine wave output?
Specifically AM modulation or changing amplitude."
The oscillator design is a Wien bridge, and I dimly recall reading
something
about the sensitivity of the bridge circuit at the dialed-in frequency. Specifically,
at a 60 Hz
frequency setting, any stray 60 Hz pickup will interact? with the 60 Hz
oscillation frequency
setting and exhibit "pulling" or modulation of the desired 60 Hz output.
I've seen this
effect many years ago with an older tubed HP oscillator (a HP 200CD).
The 120 Hz and 180 Hz frequencies are harmonics of 60 Hz and may be
exhibiting
the same "beat" with stray 60 Hz fields.
So, I'm not sure if the effect is a "feature" or a "bug", but I'd check
the 209A's power supply
for ripple, and if there are screws that connect the PC boards' ground
planes to the
chassis, make sure that they're tightened.
Perhaps someone in the group can offer further insights?
73--
Brad? AA1IP
*??? *?? *
For some April 1st fun, go to...
..
|
Figure 8-H-1 in my manual shows where the assemblies and test points are.
Do all the tests 11 down to 0 fail?
I'd do the cal constant tests (Section 8-B-11), monitoring A10 TP4 () to see if the right voltages are getting to the AtoD.? Table 8-B-5 has the voltages to look for.? The procedure is a little tricky, but you are looking to see if A10 TP4 gets different voltages as you step through the constants at this stage.
If these voltages look reasonable, I'd look at the inguard to outguard communication - there are test points on A3 in the outguard section.
Well Chuck, I don't know what to do next with this beast.? It acts as though it works but the display gives nothing useful.? Yet the display electronics seem to be working okay.
If I put a signal in, it ignores it.? Open or short on Ohms, voltage or no on volts, gives zeros and no autorange activity.? So perhaps it's an input circuit issue.? In Test I get error 11.? I press test repeatedly and it gives error numbers 10, 9, etc down to 0.
The manual sucks.? It tells me to look on module such and such but nowhere does it seem to show me which module is where.
Bob
On Wednesday, April 1, 2020, 10:22:56 AM PDT, Chuck Harris < cfharris@...> wrote:
Hi Bob, I don't see how you can come to that conclusion. The 3455A is highly reparable, and should be well within your abilities.? Lots of people have fixed their own successfully. What you won't be able to do is send its calibration module out for calibration.? You will have to do that yourself.? But, it is not any more difficult to calibrate than the 3456A. It is not my meter of choice, as I greatly prefer the 3456A, but for many, it is a useful addition to their labs. -Chuck Harris Bob Albert via wrote: >? I don't see a whole lot of encouragement here regarding the possibility of getting my 3455A working.? Maybe I will just put it aside and wait for a scrap unit to swap out boards or parts.? My 3456A still works so I am grateful for that. > Bob >? ? On Wednesday, April 1, 2020, 06:40:17 AM PDT, Chuck Harris < cfharris@...> wrote: > >? The 3455A was a dinosaur when it was first released. > > The 3455A and 3456A were sold side by side, with the > 3455A being about twice as expensive as the much more > capable 3456A.? The 3455A's interesting feature was > it was supposed to be cheap to calibrate.? All you > had to do to do a complete calibration was to unplug > the module in the back panel, and replace it with a > recently calibrated module.? The idea was you could > order up a calibration by mail, and return your old > calibration module as a core... never having to send > the full meter in for calibration. > > Interesting idea, but surely not worth twice the price > of a 3456A. > > I say it was a dinosaur, because it used all small > scale logic rather than large highly capable hybrid > circuitry, like the 3456A.? It should be much easier > to repair, but it should also be much less reliable. > > And, that is my experience with the two units. > > -Chuck Harris > > paul swedberg wrote: >> With respect to the 3455 and 3456 the difference is night and day. I have >> numbers of 3456s and was given a seriously troubled 3455. Quite a >> interesting meter. >> Replaced at least 11 actually malfunctioning chips on the logic board. The >> logics simple so easy to verify the chips were bad. No shot gunning >> involved. Never really did get it working but ended up with a different >> 3455 that needed help and the AC board and it is in fine shape. With >> respect to the old 3455 it has both a logic and voltmeter issue. The 3455 >> uses an unusual processor and teh DVM uses the same proc and a masked eprom >> that is known to go bad. It acts as a state machine. >> The 3456s are losing there eproms and copies can be found on the net. Thank >> heavens. >> Regards >> Paul >> WB8TSL >> >> >> >> > > > > > > > >
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On 4/1/20 1:45 PM, Glenn Little wrote: Has anyone seen abnormalities at 60, 120 and 180 Hz sine wave output?
Specifically AM modulation or changing amplitude. Hmm, suspicious! Heterodyning with AC ripple from dried-out filter capacitors in the power supply? -Dave -- Dave McGuire, AK4HZ New Kensington, PA
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Jared Cabot
Dave McGuire