Continuing my efforts to fix the 5065A... There was something wrong in the A7 (AC Amplifier assembly).
DC balance of the input stage was completely off-scale and one of the 1854-0023 transistors had an open junction.Luckily I had a small supply of them but I also discovered that the OP-Amps were old "seven of nines" (709). There are several different manuals floating around on the internet, and the hard copy that I have shows two different versions of A7. One with 709 and one using 741 that is also different in terms of circuit design and layout. I am considering redesigning A7 using modern CAD and also purchasing boards from a professional vendor, but first I would like to know if anyone has tried both versions and if there are any improvements. The modern 741-version uses DIP-socketed OP-Amps so that version could be tried with even better types. BR Ulf Kylenfall SM6GXV _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
