[Hallicrafters] MOD. S-38A Recap Issue - Help!
Mac McAtee
mac4 at mindspring.com
Thu Oct 19 17:32:42 EDT 2006
I just got the radio in today's mail.
I have plugged it in and it works, picks up AM and broadcasts on the SW
bands.
I started recapping it. I have replaced all the paper/foil caps except
on .25 MFD that I don't have and will order shortly.
Then I get to the electrolytic and that is where the problem lies.
I have the schematic that apparently has been with the unit since it was
new. On the parts list there is the following:
"C-29 40-30-30 mfd 150V, 20 mfd 25V electrolytic"
In the chassis is the following:
1 ea. multi part 150V cap with 80, 40, 20mfd taps
1 ea. multi part 150V cap with 50, 30 mfd taps
The two part cap has the two positive leads joined together on pin 4 of
the 50L6GT tube base. If I understand correctly, when you run caps
parallel you add the two ratings together. If that is correct that
makes that connection 80 mfd. This cap does not look like original work,
the solder connections look like they are different from the rest.
The three part cap is hooked up with positive leads as follows. 80 mfd
to pin 4 on the 35Z5GT tube base. 40 mfd to pin 6 on the 50L6GT tube
base. 20 mfd to pin 8 on the 50L6GT tube base.
I am not the best at reading schematics but it looks to me like the two
part cap with the joined leads is installed where cap C29D goes. Cap
C29D is supposed to be 30 mfd.
Pin 4 of tube 50L6 has the joined two part cap connected, a 220,000 ohm
resistor that goes to pin 6 on 12SQ7. From that pin a wire that goes to
what I think is terminal 21 on the T3 Osc. Transformer.
Does anyone have this model and can tell me the proper electrolytic caps
and the proper connection of them.
I don't know if the higher value caps are factory or changed at some
point. I also don't know why they are so much higher than what is
specified.
If I need to look at anything else, let me know. Thanks for any help
that is forthcoming.
Regards,
Mac
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