Hp 3326a Service Manual

Download HP 3326A SRV service manual & repair info for electronics experts. Service manuals, schematics, eproms for electrical technicians. This site helps you to save the Earth from electronic waste! HP 3326A SRV. Type: (PDF) Size 9.2 MB. Category METER SERVICE MANUAL.

Hi, I recently acquired an HP 3326A dual output function generator off of eBay. When I fired it up for the first time it went through a short series of self tests which it passed, after that it showed 'error 171'. This means that channel B is overloaded according to the user manual.

However, nothing is connected to the output. Channel A seems to work fine from the limited tests I have run, but when I connect channel B to a scope the output is wrong.

I do get some output, ie for the sine wave option I get a sine wave that is in the millivolts range and if I remember correctly it is dc offset up a bit too. When I run a square wave the output is not square at all, it appears more like pulses at the start and stop point of where the square wave should be. (I'll try and post pictures later.) When I run both channels together and combine them into channel A they seem to add up correctly. If I add two waves together I get an output that looks correct. I have also run all the internal self tests (beyond the start up tests) and it passes all of them. I'm hoping it's something simple that someone on this forum might be able to give me a head start on.

I managed to buy a service manual for it, and I will be going through it more thoroughly when I get some time soon. I would appreciate any head start I can get though! I do have to note that this thing is huge!

So much bigger than it looked in the ebay pictures:-) it weighs around 70lbs and when I opened the top I think that most of the structural internals are cast and machined aluminum! It is really cool looking inside I must say, and I'm looking forward to taking it apart. For the sake of helping anybody else who may run across this particular piece of equipment and have this particular problem with it I will record the solution to the 'error 171 - channel X overloaded' on my HP 3326A function generator. Being relatively new to the repair game it took me some time to work through everything and get a sense of what was going on, and what was causing the failure. As I mentioned earlier, I narrowed it down to the high voltage board (opt 002) for channel B. The symptoms showing on the board were: A: Zener diode CR117 had failed B: Pico fuse F502 was open C: Capacitors C113 and C114 were shorted to ground It took me a while to get see that the capacitors had failed as I was playing around with the fuses and zener diode (which I found first), thinking that they were somehow at fault (rather than a symptom).

Pico fuse F502 is not shown in the attached diagram, but is in series with the -28V circuit coming from the power supply. In hind sight it is fairly easy to guess what was may have happened. Somehow someone overloaded the output and this shorted the caps on the output (C113 and C114). This internal short caused the perpetual error on the generator. Of course as everybody has already mentioned, the answer was a short on the output. Just took me a while to find it. Attached is the relevant part of the schematic.

Hope it helps someone.

• DEPARTMENT OF THE ARMY TECHNICAL BULLETIN CALIBRATION PROCEDURE FOR SYNTHESIZER/FUNCTION GENERATOR HEWLETT-PACKARD MODELS 3325A( ) AND 3325B( ) Headquarters, Department of the Army, Washington, DC Approved for public release; distribution is unlimited REPORTING OF ERRORS AND RECOMMENDED IMPROVEMENTS You can help improve this publication. If you find any mistakes or if you know of a way to improve the procedure, please let us know.

• Final procedure. IDENTIFICATION AND DESCRIPTION 1.

Test Instrument Identification. Calibration of Synthesizer/Function Generator, Hewlett-Packard, Models 3325A( ) and 3325B( ). The manufacturer's manuals and TM 11-6625-3065-14 were used as the prime data sources in compiling these instructions.

Referred to as the TI (test instrument) throughout this bulletin. • Test instrument parameters Harmonic distortion (relative to fundamental at full output) Amplitude modulation Square wave Ramp retrace Frequency Sine wave Square wave Triangle Positive slope ramp Negative slope ramp Phase offset Amplitude Amplitude accuracy with no attenuation (attenuator range 1) into 50 load (no dc offset ) Flatness with no attenuation. • TB 9-6625-2049-35 Test instrument parameters Amplitude accuracy with offset attenuation (range 1) into 50 load Attenuator accuracy (these errors are additive with the amplitude accuracy errors) Amplitude output Amplitude (option 002) (high voltage output) Dc offset Dc offset (option 002) Dc plus ac Not verified below 50 Hz. Accessories Required. Usage accessories, issued as indicated in paragraph 4 above, and are not listed in this calibration procedure.