I bought an HP 651B test oscillator on eBay, the listing said "This has been tested and it is in good working order".
When I powered it on, I was not able to get a signal out of either of the output jacks, nor was I able to make the needle move. I did get it to bounce when switching some of the knobs and things, but that's it.
I was about to return it, but I thought "Maybe I'm just an idiot". Does the needle only move when connected to a proper load? Is running this straight in to my oscilloscope not the correct way to test it? I would much prefer to keep and use this unit than return it, so if theres any possibility that it was user error, I'd like to correct that.
When I powered it on, I was not able to get a signal out of either of the output jacks, nor was I able to make the needle move. I did get it to bounce when switching some of the knobs and things, but that's it.
I was about to return it, but I thought "Maybe I'm just an idiot". Does the needle only move when connected to a proper load? Is running this straight in to my oscilloscope not the correct way to test it? I would much prefer to keep and use this unit than return it, so if theres any possibility that it was user error, I'd like to correct that.
I'm not familiar with this machine, but I'll give your thread a bump.
The operating instructions say: "Connect load to output connector having an impedance which matches impedance of load".
https://ia903200.us.archive.org/0/items/manualsbase-id-422343/422343_text.pdf
There is also mention of "feed-thru terminating resistances" (50 or 600 ohm).
The operating instructions say: "Connect load to output connector having an impedance which matches impedance of load".
https://ia903200.us.archive.org/0/items/manualsbase-id-422343/422343_text.pdf
There is also mention of "feed-thru terminating resistances" (50 or 600 ohm).
Ask the seller how to test it seen as the seller states it was tested.
Also there are YouTube videos of testing and a good thread here:
https://www.eevblog.com/forum/testgear/hp-651b-test-oscillator-teardown-and-repair/
Also there are YouTube videos of testing and a good thread here:
https://www.eevblog.com/forum/testgear/hp-651b-test-oscillator-teardown-and-repair/
Turn the output attenuator knob and the fine/coarse knobs all the way clockwise. The needle should be pegged regardless of a load being attached or not. If you still have no needle movement, something is wrong with it.
