Newish here... My quest for cheap test gear has lead straight to an interest in repair skills...to that end:
Here's a Lambda LES-F-04-0V 0-60v, 0-15A PS I got for some motor control experimenting around. Built around 1985, catalog
http://us.tdk-lambda.com/ftp/catalog/le_fall85.pdf shows specs of line regulation 0.02%+2mv, load regulation of .02%+4mv from 0 to 15A, (nice...) noise 100mV pp (...not so nice), over voltage protection to crowbar and shut down the output. I assume you have to set this to not be tripped by the normal voltage adjustment. Nice if say, the motor feeds power back during a quick ramp down which might kill the driver I guess.
Initially, I powered it on, started to adjust the voltage and heard a crackling, loud, arcing sound and powered off all within about 1 second. I suspected a capacitor arcing because it didn't have the buzzy quality I have heard transformers make.
I opened it up, starred in wonder at the sturdy/heavy duty quality of it, and considered "what was what" in a block diagram kind of way a while, was able to power on a few minutes with some DMM connected to check values/probing and discovered a shorted big filter cap I'm look for a replace of. It was drawing 10A set to Ov output which increased rapidly going to 1V out (briefly).
A couple questions:
Can anyone improve on my vague block diagram understanding? I find that key to repairing equipment without schematics or documentation. If you know the block diagram level of say, RF transmitters, etc. you can look at scope/DMM values and quickly find roughly where things are awry IF you can power it on and not smoke it.
Also, just studying each of the 2000 components one by one for signs of failure. The bad cap wasn't bulging, leaking nor getting hot (just a barely noticeable amount) dispite the 10A (1000 watts???) draw. (Maybe power factor, clamp on meter funnyness at work...)
I know caps after 30 years are prime suspects. Any other guiding advice for this kind of repair adventure? Tips, tricks, strategies or perils? I'm looking to buy a "blue" ESR meter but this cap appears shorted (under an ohm I think) and I wonder if it would read bad.