Hey all.
I have an old HP 204C that I mainly use for troubleshooting guitar amps and pedals (inject a 1 volt 1k sine into the front end of an amp or pedal and figure out where the signal stops).
The problem is that the 204C has this problem:
When the dial and factor switch are set to a particular frequency (say 1 on the dial, x1k on the selector) the frequency seems much slower. Now, I may be testing this wrong, but I took a Fluke with frequency counting and put it with banana plugs right into the 600Ohm outs on the front.
I got the following:
Lowest selector (x5), dial at 1 = 14.09 Hz
Dial at 1 and selector at x1k = 2.76 kHz
Where I use it (1volt at 1k) is achieved by setting the selector at x100 and the dial at 3.8 (which should be giving a 380 Hz wave)
Now, I am not testing with a scope and maybe when you just output the sine directly into a Fluke you affect the reading, but does this seem right?
I have not opened it up. I am handy with a soldering iron, can read a schematic, and know my way around Mains voltages (and 400+ vDC tube amp B+) so feel free to suggest. I downloaded the service manual, but to service it, you need a whole bunch of test equipment I don't have.
I could just leave it as is and know where I need to set it to trick it into giving me the wave I desire, but if it is just a few resistors that have floated due to age and heat, I wouldn't mind making it close to correct as possible.
Thanks guys
I am not an EE but have learned a bunch on this forum)