VT100 PSU smelling.

Jules Richardson jules.richardson99 at gmail.com
Sat Jan 23 10:13:19 CST 2016

On 01/22/2016 06:26 PM, Tothwolf wrote:
> The translucent yellow Rifa (now owned by Kemet) class X/Y safety
> capacitors in particular have a 100% failure rate and are on my
> replace-on-sight list. They usually begin to show visible signs of cracking
> in their outer casing before they finally go out with a bang.

It's a well-known fault, but has anyone ever known one fail and actually 
cause any damage (other than to itself)? AIUI, they're there to reduce 
noise from the device leaking back out onto the AC supply - a system should 
run quite happily without them.

I've had maybe four or five fail on me over the years, out of several 
hundred systems. They're a definite weak spot, but given that I've never 
heard of one damaging anything it's the sort of thing I'd consider doing 
only if I was carrying out some other repair work on the PSU.

 > I usually replace them with a film capacitor from Epcos of the same
 > value and safety class.

Is the voltage rating on the US ones different (new vs. old)? I can't 
remember now. I know all the old UK ones seemed to be 250V, while modern 
parts were rated at 275V.



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