20 Jul
2006
20 Jul
'06
4:45 p.m.
O.K. - now on to the power supply.
The +5v channel 1 supply is good, 69 mV peak to peak AC noise (measured on a scope with AC
coupling)
the +-12v channels are ~292 mV of noise
the -5v channel has 500 mV of noise, even with an additional 1000 ?F capacitor across the
output (to hopefully filter this junk out)
(-5V also has periodic fluctuations at a lower frequency)
All of this is high-frequency, excluding the -5v hum.
In short, it doesn't look like adding an external filter cap will help much, unless I
go all the way and throw in a LC filter.
Pulled the P/S apart, and the board with +-12V and -5V has peculiar capacitors mounted on
it - 3 lead Mallory Aerovox.
Are these really the multipart electrolytics that went out of style (I thought) with solid
state?
The wiring is 2 leads connected to one side of the power rail, one lead to the other.
Could twin-lead caps be substituted?