Refurbishing RE Designs LNPA 150 Amps

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deanr

Refurbishing RE Designs LNPA 150 Amps
« on: 26 Mar 2020, 12:14 am »
With a little more time on my hands at home these days, I plan on replacing the electrolytic caps in my RE Designs LNPA 150 Amps (made by Dan Banquer).  I wish Dan was still around to ask, but there seem to be some knowledgeable people on here, so don't be shy.

Here are the amps.


An overview, looking down at the two mono amps.


I bought these used so I don't have their complete history but they seem to have the Vishay bulk metal foil resistor upgrade.

My first question - There seems to be a powdery/crystalline substance on the inside floor of both amps.  See pics below.  Is this leakage from the big electrolytics, or is it some kind of old heat grease used on the bridge rectifiers?  Or maybe it is degraded sealant that was intended to prevent corrosion of the aluminum case, or just junk that blew in the vent holes?








deanr

Re: Refurbishing RE Designs LNPA 150 Amps
« Reply #1 on: 26 Mar 2020, 10:10 pm »
These mono amps are supposed to be twins, but the caps on what seems to be the power regulation board don't match up from amp to amp.  It does seem symmetrical between the positive and negative rails in each amp, but the caps in the first amp (pair of 47 uF 100V) are different from the pair in the second amp (100 uF 63V).

When replacing the caps, do I replace them exactly as I find them, or do I make each amp the same?
If I go for uniformity, which amp sets the standard?

mresseguie

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Re: Refurbishing RE Designs LNPA 150 Amps
« Reply #2 on: 26 Mar 2020, 10:15 pm »
Deanr,

Knowledgeable folks may well respond here, but you may have better luck getting responses in "The Lab" circle. I don't have any experience with this.

Michael