As usual, Mark Persons expresses his love for our craft by sharing useful information!  His article in the November 8 RW issue, "What to know about three-terminal voltage regulators" highlights an inexpensive "cure" for unwanted regulator-oscillations. It reminded me of three experiences from my earlier days:

We had a nice audio-console in our production control that started to show odd distortion on peaks. I checked its main program-module with a 'scope, and saw one three-terminal regulator would break into oscillation when I raised the audio level near full-scale; replacing a simple electrolytic fixed that!

The second example was in a different device (can't recall which one) which its manufacturer returned to me as "unrepairable". I was able to fix THAT one unexpectedly by replacing a little disc-capacitor in the regulator circuit.

A third involved one of the modules in our STL-transmitter.  At first, the only "normal" method was to buy a new complete replacement-module ($$$).  I started to investigate and found it contained a small switching p/s. which we was able to buy  (much-cheaper) from a third-party source (now, only $$).  Still-curious, I took the baddie module apart and found ONE easily-replaceable ELECTROLYTIC CAP (WOW! only $0.cc)  After that, I was able to cheaply and quickly repair future "baddie" modules (except for one whose switcher failed for other reasons... good thing we'd bought TWO of them!)

While we've transitioned to newer, more-compact and -efficient technologies, the ability to fix "stuff" on our own (and save money in the process) is sadly slipping away. Let us celebrate our "MacGyvers" who can keep things going... and folks like Mark who generously share their knowledge!

Cheers & 73s,
-Michael Shovan, WB2KHE, CBTE

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