HP-23 Question

[Neil Morrison]

1) Tolerance on the caps is so high you don't need the 27uF. I wouldn't do
this because you'd have to watch for the ripple current, and I have no idea
how it would divide. If you do have to parallel, use two by 100 uF, not odd
combinations, but it's better to try just the 100uF first..
2) Yes, definitely replace both caps, not just one. And if the output ripple
voltage is too high, add more capacitance on the output side as well if you
can find high voltage caps. It wasn't unknown to put two caps in series, but
you have to add resistors in parallel to ensure the voltage is evenly
divided.
Just my opinion, YMMV.

Regards,

Neil

----- Original Message -----
From: "Carl C. Miller Jr" <bugmarx at EV1.NET>


Hello All,

I am replacing one of the electrolytics in the high voltage (800 volts)
section of the power supply. I have two questions:

1) I could not find an exact replacement for the cap at my favorite
electronics store. I found a 100uF at 450 volts and also a 27uF at 450
volts. The voltage rating on the original is 500 volts. Could I parallel the
100 and 27uF caps and would they work okay without exceeding their voltage
ratings?

2) Since I am replacing one of the two voltage doubler caps with an inexact
replacement, should I replace the other with the same parallel combination
to maintain some balance in the doubler circuit, or is balance even a
question?

Thanks in advance,
Carl

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