[frsimen]

Hello Mark,

There's quite a lot that isn't right from your photos. I have measured the results from my 9082, which is very similar the 9081, so the results should be valid. The generator was switched to the 64-128MHz range and tuned to the highest frequency, 134.9MHz, tuning set to fast and 6.25kHz steps.

Starting at TP17. There is a 10V peak to peak near square wave of period 600ns.

TP18, I couldn't identify positively, but what I think is TP18 has a similar waveform to TP17.

TP19 has a waveform that is 12V for 2.5ms and 0V for 0.5ms, repeated.

TP20 has a square wave with some ringing. The base line is about -1V and it rises to +10V. Period 600ns.

TP15 has a 3ms period near square wave, 12V peak to peak.

TP14 has a tricky to trigger on waveform. The base line is at +12V, with 0V pulses of 600ns width every 200 microseconds.

TP7 has 12V pulses that alternate between a single pulse and a double pulse. All pulses are 10 microseconds long, and the double pulses are separated by about 10 microseconds. Between the start of the double and the single pulse is 175 microseconds, from the start of the single pulse to the start of the double is 150 microseconds.

TP8 had 12V 600ns pulses, every 330 microseconds.

TP9 and 10 both have a very short 0V pulse on a +12V baseline when locked. The pulse is too short to measure accurately with my 'scope.

From the above, your problem seems to be early on in the divider chain. Check TP19, I expect that won't be right either. The counters won't do much counting unless the clock is present and that is missing at TP17, before it reaches the counters.

It would be worth checking that Q6 and Q7 are in good health, although if the voltage at TP19 is permanently high that will be enough to stop things working all on its own. To confirm that the clock is missing, check pin 15 of IC5, where you should see a waveform that matches what I had at TP17.

Paula