So I recently picked up an R&S NGPE 800W power supply and it was listed as untested. I tested it and found the current sense circuit was acting as if it were pulling 50A so I couldn't get anything out of it. I tested a few things and found the +15V rail was at +13.8V. +13.8V and -15V obviously doesn't work well with op amps. Searched all of the boards and found some burnt tantalums and cut them out. Every single tantalum near the +15V regulators were burned. After cutting them out and replacing with aluminum electrolytics I actually had I turned it on and pop, one blew up. Good news is the original fault is gone, doesn't think it's pulling any current. The bad news is I can't turn it on for more than a few seconds without a new tantalum blowing up on me. That's my question... Do I need to replace every tantalum now with a new tantalum or are aluminum electrolytic caps usable? Also is there any good way to clean the electrolyte from those stupid things? Scrubbing with towels and alcohol is going to take a long time even for just the 3(thought 3rd time might be the charm) that have blown up.
These tantalum capacitors may be in there for ESR, so you can't easily replace them with other types, especially not electrolytic ones, only by high capacitance MLCCs, because these also have low ESR, probabaly lower one.
But pay attention, the latter could also pose a stability problem.
Get the schematics, and you may decide, what to use. LDO regulators for exmple example very well selected ESR and capacitance, also several switch mode chips .
Tantalum capacitors don't have a special end-of-life endurance, normally they last forever, if nothing is wrong. In contrast to electrolytic cap's, which have a rated life time over operational temperature.
So that systematic failure indicates possible failures in the circuit.
Ta cap's fail due to overvoltage, spikes, excessive ripple, latter is equivalent to excessive inrush current.
If you design Ta cap's directly at the low ohmic battery or behind a regulator, you have to limit that inrush current, i.e. artificially increase its ESR by a series resistors in the ballpark of several ohms.
Please check the location of the failing cap's!
2nd is overvoltage, so you should measure the steady voltage (and the ripple) at the intended location, before assembling new ones.There should be enough voltage margin, best is a factor of 2.
If even a new electrolytic capacitor blew up, which is much more forgiving, then you have to check ripple current, and select the appropriate quality also.
In an 800W PSU, heavy ripple currents @ 60Hz are expected but only under load, so there maybe a short circuit somewhere, which causes ripple w/o load, and especially highr ripple than in normal use.
Therefore check current consumption w/o load, first.
Frank