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Old 28th Jul 2020, 4:30 pm   #10
Join Date: Mar 2015
Location: Milton Keynes, Buckinghamshire, UK.
Posts: 69
Default Re: Marconi TF2431 Counter Service Manual / Schematic

I spoke too soon.

After fixing the AGC detector fault, I am still seeing HF parasitic oscillations / ringing in the wide band amp and the schmitt trigger.
Whatever the problem is, the result is false counter readings.
It appears to depend to some extent on the input signal and the AGC gain setting. Without a service manual I'm not sure how to set the AGC gain trimmer.
I haven't figured out if this is a design problem or a fault condition.
I'm still investigating.
brian_mk is offline   Reply With Quote