25 Jul
2012
25 Jul
'12
2:12 p.m.
The frequency of the ripple is indeed 120 Hz.
--------
Paul Anderson -- VE3HOP
On 2012-07-25, at 3:23 PM, ard at p850ug1.demon.co.uk (Tony Duell) wrote:
The ripple is on the output. I figure the filter cap is causing the
problem.
Right. I think that is a problem. Firstly, what is the ripple freuqency?
If the capcitor is the problem it will be twice the mains frequency (so
120Hz for you I guess). If it's at mains frequency, the problem is likely
to be that half of the full-wave rectifier isn't working, maybe an O/C
diode, less pleasantly an open-circuit in half of the transformer secondary.
As for the capacitor, I think you said the original was 4000uF [1]. I
would fit a 4700uF, the extra capacitance won't matter and it'll be
easier to get.
[1] Why this is _necer_ [2] written as 4mF is beyond me
[2] Actually, 'never' is too strong. I am pretty sure I've seen at least
one schematic that does thta, maybe an HP one.
-tony