[time-nuts] Resoration of 5065A - continued...
ulf_r_k at yahoo.com
Mon Sep 11 05:56:23 EDT 2017
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
Ulf Kylenfall SM6GXV
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