[Collins] 30S-1 problem..

[Rolynn PRECHTL K7DFW]

> Perhaps the socket or the wiring is getting less than 6.3 volts to the
6AL5. There's nothing OUTSIDE the tube that could make one heater dimmer
than the other, besides low voltage (heaters probably in parallel inside the
tube) and some difference in heating.
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If he has a 6AL5 in the 30S-1 it's the wrong tube. The circuit calls for a
12AL5.

There were two different circuits for the ALC using tubes before the SS
change. The first had the 12AL5 filament powered directly from the
transformer and second had a 47 ohm resistor (R234) in series.

The last change was to eliminate V203 and go SS.

K7DFW

..._._