Re: Switching power supplies

Chuck Harris

Tough question.

Yes, switching supplies are inherently harder on
components than linear, but they also use much better
parts. And they are more likely to be designed using
math, rather than rules of thumb. And they are more
likely to have extensive protection devices to prevent
catastrophic failures from occurring.

Linear supplies are heavy, are more likely to break your
toes, and make copious amounts of heat. That heat soaks
into everything around them, and causes component failure.

Tektronix used some really uber parts in their 70's vintage
supplies. In some cases, I cannot find modern parts that
were as good as what they used.

I would take it through calibration, testing the ripple
and voltages, and just use it. If it fails, fix the failure.

Odds are very, very, good that in prophylactically replacing
parts you are going to introduce failures, now and in the
future. Replacing a 10,000 hour rated part with a 1000 hour
part, isn't going to improve reliability.

-Chuck Harris

Brendan via Groups.Io wrote:

I have a few questions about power supplies and would like some opinions. Are switching powers supplies inherently harder on components than linear power supplies? If you picked up a 70's-80's vintage scope with a SMPS would you replace power supply components before using it as a daily driver? Or do you treat all power supplies the same and visually inspect, check for ripple and call it good? From my reading it seems that when a SMPS melts down the chain reaction damage has the possibility of being bad.


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