Derwin wrote:
I tried to re-cap a tube receiver (amplifier + tuner), and now when I turn it
on it starts playing music for a few seconds after it warms up, then the music
fades out and and hum takes over. I don't really know what I'm doing, and the
wiring inside looks like a mess of spaghetti. I'm pretty sure I replaced the
caps properly, but I used .068uf WIMA caps to replace .050uf wax/paper caps,
and I'm wondering if the value difference, added up over 8 caps would make a
difference? Other than that, does anyone have any advice based on my
description of the unit's behavior? Any comments whatsoever might be helpful..


Obviously what you did caused the problem. Check for cold solder
joints and inadvertent connections via solder flash. If you have
enough information (e.g. a detailed log of what you did, or
before/after photos), go back and recheck your work.

Did it look like spaghetti before you started?

From your description, it sounds like maybe it's drawing more current
now than before, so that the power supply capacitors are no longer
adequate. Does it have a rectifier tube in the power supply? Is it
glowing red? Perhaps you've dramatically changed the bias point in
the output stage by some misconnection.

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