Arthur Pozner wrote:

Folks, I dismantled this silver puppy. And here is what we found! The
RF board dated 2004.4.15 . TWO PVC tuning capacitors. PVC1 has 4
built-in trimmers,PVC2 got none . PVC2 appears to contain more plates.
IC1 is TA7358AP. Circuitry is indeed purely LC based analogue- there is
not a single crystal in the oscillator/mixer area . So, if the variable
capacitors are using pvc as an insulator I can imagine that would
partially explain such wild frequency drift due to temperature changes
How stable is TA7358AP?

That's why the Panasonic RF-2800 & RF-2900 had a drift problem. The
S-350 is apparently modeled after those two receivers. They used
miniature tuning capacitors like the kind found in small analog
transistor radios. They have thin plastic insulators, probably
polyethylene. The drift can be minimized by adjusting (relaxing) the
compression on the stack of plates and insulators but I don't advise
doing this if you've never had one of these variable cap's apart. There
are many small parts.


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