Author Topic: About HP8903A. Other version of output attenuator A6 board.  (Read 274 times)

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Offline BlancTopic starter

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About HP8903A. Other version of output attenuator A6 board.
« on: September 23, 2024, 12:22:54 pm »
I need someone's help to resolve my long-standing frustration.

A few years ago I acquired a used HP8903A.
Completely restored except for output the attenuator board A6. Because my HP8903A has a different version of the A6 board. Looking at the service manual, the A6 board has two large relays. However, my A6 board has three large relays.

If anyone has a service manual for the 3-relay version A6, please provide the A6 circuit diagram and troubleshooting steps page in PDF or other format.

My HP8903A is working very well up to 60mV rms output. However, if the value is lower than that, the output amplitude will be 10 times the specified value. For example, if you specify 6mV rms, the output will be 60mV rms. So if you want to get 1mV rms, specify 0.1mV rms. It's not that serious, but it's annoying.

The service manual I have has detailed instructions on how to repair the A6 board. Unfortunately, this explanation doesn't work for my other version of the A6 board.
 


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