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Kohler 15RMY81

stretch67

Registered
Thanks for the information so far.

Wehave got the unit to run.
It will not make power.
It will make power if we flash the field with 12 volts but once the 12 volts is removed it will not make power.

Where should we start to look next?

Trouble shooting info would be great.

Thanks
Jeff
 

Birken Vogt

Email NOT Working
Most likely that voltage regulator PCB is no good and I don't think they are still available and Flight Systems does not repair them. Trouble is, it also includes the overspeed and it is for the low ohm Kohler rotor.

It could also be the SCR pack you see off to the side, or bad connections. The wiring diagram is pretty simple, just excite it with 12V and make sure voltage is making it to all the places it should be.
 

stretch67

Registered
Hello

Thanks for the info. I will pass it along
Will keep looking for more info.
not good news on the regulator being hard tpo find.

Thanks

Jeff
 

Zephyr7

Registered
Hello
Thanks for the info. I will pass it along
Will keep looking for more info.
not good news on the regulator being hard tpo find.
If the regulator is not potted, and you have some soldering skills, it is probably repairable. It’s usually either dried out electrolytic capacitors or power devices (transistors, etc) that fail. Resistors sometimes burn up, but those are usually easy to spot visually. For a repair, just replace the suspect parts (all electrolytic capacitors, all power transistors) and give it a try. Probably less than $20-30 in parts. Don’t even bother trying to diagnose anything. A lot of times a rebuild like this will fix things.

Don’t try this unless you’re certain the regulator board is at fault.

Bill
 

stretch67

Registered
Not a potted board.
Give the fact that the unit sat the last 10 years I a unheated shed, i am pretty sure that the card is going to need looking at. Only 70 hours on the unit.

Thanks for the help.

Jeff
 

Zephyr7

Registered
If you try the rebuild on the board, grab a can of conformal coating (techspray sells rattle cans of the stuff), spray everything except the adjustable part of pots and wiring terminals when you’re done. That should seal it from future moisture issues.

Bill
 

Zephyr7

Registered
I'm pretty sure these boards had a similar coating when new, but the components just got old and gave up.
I would think so too, but I’ve seen some boards in old control cabinets that either had no coating, or the coating was damaged. I’m not sure what would strip the conformal coating off of old boards, but I’ve seen it before.

Bill
 

stretch67

Registered
I have conformal coating and a reallyt good re work station.
Board is coming out this weekend and I hope to have time to look at.

My oldest daughter (14) is going in for major back surgery in 2 weeks so a lots of stuff is getting put on hold for a bit.

I will let you know how the fix goes ok.

Thanks
 

Birken Vogt

Email NOT Working
Should be a 269315 originally, superceded to a 239479 I believe.

I asked FS about this some years ago when I did one, they said they did not repair it any more even though it had an old FS tag still on it. I had to adapt it myself to an aftermarket unit and was not happy but the owner wanted it that way. Trouble is it includes the overspeed module so lots of kludging required to make it work.

There are still a fair number of these out there working.
 
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