Hi all,
I have problems with the calibration of my HP 339A Distortion Analyzer. According to the manual at the ADJUSTMENTS SECTION V 5-10, I zeroed the meter without power and the result is okay (Pic 1). But when I switched on the 339A there is a deviation (Pic 2).
The next problem is that I can't adjust the 3 Vrms according to 5-12. The maximum voltage I can adjust is 2.93 Volts (Pic 3).
My power source unfortunately is not an AC calibrator but a HP 3325A with a quite clean 1000 Hz signal at 3.0005 Vrms.
Does anyone has an idea where to start the trouble shooting?
Many thanks in advance for your help
Michael
I have problems with the calibration of my HP 339A Distortion Analyzer. According to the manual at the ADJUSTMENTS SECTION V 5-10, I zeroed the meter without power and the result is okay (Pic 1). But when I switched on the 339A there is a deviation (Pic 2).
The next problem is that I can't adjust the 3 Vrms according to 5-12. The maximum voltage I can adjust is 2.93 Volts (Pic 3).
My power source unfortunately is not an AC calibrator but a HP 3325A with a quite clean 1000 Hz signal at 3.0005 Vrms.
Does anyone has an idea where to start the trouble shooting?
Many thanks in advance for your help
Michael
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Hi Tabloka, Michael:
If you have the manual, it describes how to adjust the needle using two pots.
One for the left side (0,0) and one for the right side (0,1) of the meter.
I forget where exactly the manual say to set the needle.
Unfortunately, HP screwed up the manual, use the other pot that is described in the
manual, that is for the left side (0,0) use the trimmer the manual advises
for adjusting the right side (0,1) and vice versa.
It was listed in the changes to the manual.
Hope that helps at least it points you in the right direction.
Cheers,
Post Script - If you get board, there are a couple of HP339A threads with good information in them.
And then there is the HP339A in the Wiki. Maybe if you search you'll find it.
If all else fails you can go to the Low-distortion Audio-range Oscillator thread (LINK)
and around posts 1495-2500, +- 750 there is raw trouble shooting and upgrade information there.
If you have the manual, it describes how to adjust the needle using two pots.
One for the left side (0,0) and one for the right side (0,1) of the meter.
I forget where exactly the manual say to set the needle.
Unfortunately, HP screwed up the manual, use the other pot that is described in the
manual, that is for the left side (0,0) use the trimmer the manual advises
for adjusting the right side (0,1) and vice versa.
It was listed in the changes to the manual.
Hope that helps at least it points you in the right direction.
Cheers,
Post Script - If you get board, there are a couple of HP339A threads with good information in them.
And then there is the HP339A in the Wiki. Maybe if you search you'll find it.
If all else fails you can go to the Low-distortion Audio-range Oscillator thread (LINK)
and around posts 1495-2500, +- 750 there is raw trouble shooting and upgrade information there.
Last edited:
Did anyone ever find a replacement LDR for the HP339A?
If so, which was it? If you have good working two, four, or six,
LDRs please PM me.
Cheers,
If so, which was it? If you have good working two, four, or six,
LDRs please PM me.
Cheers,
Hi SyncTronX,
what a mess in the manual. I found the part where HP switches the pots. You can find it in the Change No. 38 as the last enumeration.
I quote:
Page 5-7/5-8. Figure 5-3. Switch the part designators and adjustment descriptions on A2R37 and A2R17 shown in the lower left corner of the drawlng.
So I did it as the now 'changed' manual says and it works!!! GREAT!
Thanks a lot for the lightning fast and exact hint. I never read any of the changing stuff in the manual - until now. Now its time to continue the calibration.
Best Regards Michael
what a mess in the manual. I found the part where HP switches the pots. You can find it in the Change No. 38 as the last enumeration.
I quote:
Page 5-7/5-8. Figure 5-3. Switch the part designators and adjustment descriptions on A2R37 and A2R17 shown in the lower left corner of the drawlng.
So I did it as the now 'changed' manual says and it works!!! GREAT!
Thanks a lot for the lightning fast and exact hint. I never read any of the changing stuff in the manual - until now. Now its time to continue the calibration.
Best Regards Michael
Hi Michael,
Glad I solved your issue 🙂 I know because I went through the same thing
in a WTF moment, made things worse off. Until I happened to think of looking
at the changes and then fixed my meters display.
Yes, I couldn't recall the name, Full Scale ADJ and 1/3 Scale ADJ.
I'm glad you could make it out what I was saying too.
Thanks for the pdf of the change. I should put that in the 339A wiki
as it's and important piece of information.
Prost,
Glad I solved your issue 🙂 I know because I went through the same thing
in a WTF moment, made things worse off. Until I happened to think of looking
at the changes and then fixed my meters display.
Yes, I couldn't recall the name, Full Scale ADJ and 1/3 Scale ADJ.
I'm glad you could make it out what I was saying too.
Thanks for the pdf of the change. I should put that in the 339A wiki
as it's and important piece of information.
Prost,