Lionel 6-12867 PM-1 problem

@redbarchetta81 posted:

I’ve got a 6-12867 Powermaster . Yesterday , I went to use it , and don’t know what happened ( it was wired track power correctly ), and when I powered it up , I smelled that dreaded electrical smell .

It still works ,???? No, by definition, it is NOT working.

and is a spare , but now there’s no throttle / brake control .Again, definition of not working- it's not controlling power output- stuck on is NOT working.

In other words as soon as the center rail & ground make contact on the locomotive , it begins to run on its own . No way to control via cab-1 . Again, not working, stuck on output and burned out smell is a total failure.

I’ve not tested it in command as the spare command base is in the box stored . Command mode has nothing to do with the powermaster. It is just a mode for full on power. The powermaster is NOT interacting with the TMCC signal.

  What burned out ( I sheepishly ask)?🥹 Again, the power control section, but maybe more.

Searching for technical details, I only found this video.

https://www.youtube.com/watch?v=qRmuNFU459A

Also, appears they might have used FETs rather than a TRIAC as the power control but basically repair is replacing the damaged parts hoping none of the logic section was damaged.

https://ogrforum.com/...l-powermaster-repair

If you cannot repair it yourself, paying someone quickly becomes impractical.

Forum sponsor trainz and possibly other sources, you can pick one up working for $50

@ VernonBarry ,

Personally , from what I’ve seen in the videos of repair : The Transistors ( outputs) IFR540N Mosfets may well be an issue  it wasn’t sitting there on with voltage thru the cab-1 being supplied more than 10 seconds before the PH-1 breaker tripped . & Nothing is remarkably odorous around the insides ( I.e) electrical , so that’s what I gather it could be .

Anybody know which mosfet controls the conventional voltage ? Although I have a voltmeter my wife bought me @ xmas , I don’t know how to use one .

Looks like Q2 and Q3, here's the schematic of the original PM-1.

Lionel PowerMaster Schematic.pdf

Thank you GRJ . 😀