VT100 PSU smelling.

Tothwolf tothwolf at concentric.net
Sat Jan 23 21:00:15 CST 2016

On Sat, 23 Jan 2016, tony duell wrote:

> Incidentally, some machines have those sealed metal cans containing 
> filter capacitors, inductors and sometimes discharge resistors [2]. Has 
> anyone ever had the capacitors in one of those fail?

Actually, yes. I had one fail in one of my scopes. I don't recall the 
brand/series right now, but it is apparently a known issue with that 
particular series of filters. I still need to replace the same filters in 
the other scopes since they will most like do the same thing eventually.

> [2] I wish the manufacturers would print a schematic on the can, or at 
> least in an available data sheet. If I measure a 1M leak to earth from 
> the live pin (say), I want to know if it's a deliberate discharging 
> resistor or a leaking capacitor.

Most of the IEC320 input filters I've used have a schematic on the can or 
in the datasheet. They are usually also careful to denote the 
medical-rated filters which lack the Y-type safety capacitors between the 
two supply terminals and ground.

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