MEP 804 A

[Jackb379]

I’m new to the site and MEP 804 A ownership. I/ we being my church bought this one as we’re having church in a tent do to No/ COVID 19. Anyway I started it up after servicing it and it runs great but when I checked voltages in 120/208 Mode each leg shows 170 volts From L1,L2, L3 to L-0 and no adjustment changes it one way or another. Anyone have a clue as to where to start . I found a document on testing the voltage regulator and theresults seems to show it’s bad? But they aren’t easy to find it’s a PN# 19870? Any help would be highly appreciated. I was able to locate a part # and get a quote ona kit @$1600.00 . this is a lot of money for a ppssible resolution?

 

[Zed254]

You might want to read the thread you just posted to: https://www.steelsoldiers.com/threads/mep-804-over-voltage.192930/#post-2308491

A TB is listed and suggestions about exercising switches and applying contact cleaner to them.

 

[Zed254]

TMs for the 804A here: https://www.steelsoldiers.com/threads/all-the-tms-you-need-to-work-on-the-mep-804a.148936/

 

[PrivateB2]

Im aware this is an older post. Ive been working with the regulator listed and have found a few issues with them so far. Upon examination of a few I have found a common issue of a small carbon arc build up between two terminals under the connector. It seems to follow the curve of the connector itself.
The next issue I found are the two mosfets. They short out on some even with a good excitation field.
The other odd thing I have seen, which I'm not sure if this is just me freaking out, but one of the heatsinks runs right over top an input to the lm324n comparator.
Ive been bench testing them for now on a component level with an open loop test as ive never gotten the Potential transformer(ive yet to find a trashed unit to rip one out of lol. )