Hi,
Thanks for all the replies - I'm a bit like the rabbit in the headlights - and beginning to realize how much I don't know!
As a bit of background, the signal gen is a HP 8656A and has no output. Looking at the output on an SA I see some sort of haphazard signal that appears to be sweeping rapidly over the entire output range, but there is no stable output anywhere - so it is pretty broken. Working through the T/S manual I have verified that all the power rails are good and the attenuators all seem to be working (no sticking etc).
The manual next suggests setting the frequency to 500MHz at 0dBm and checking the oscillator input to the main output amplifier stage (A6). This should be 500MHz @ -3 to +4 dBm.? It is the input from the main oscillator to the dividers,filters and output amplifier. I believe this checks whether an appropriate signal is entering the A6 board but it not leaving it correctly.
This is the stage at which I posted my original question regarding probing the trace as the manual suggests doing this with an SA and I've never used a probe on my SA.
thanks
Tony
