MEP-003a too much voltage

[delvin00]

My MEP-003a has been working great until yesterday. I started it and walked away to let it warm up. When I returned the voltage was 300+ with each leg measuring 150+. Can anyone help with info on what may have malfunctioned and what I need to do to correct it. This unit only has 10.5 hours on it. I have put 8 of those on it and have had no problems. Thanks!

 

[doghead]

Please add your State to your location information. This is a site requirement.

What was the HZ reading? did it simply warm up and rev up?

Have you idled it ever? This is known to ruin the voltage regulator.

 

[delvin00]

I am a new member and am from North Carolina. Sorry for the deletion of the state. I have never idled the unit. The hertz were 60 and it never reved I was a few feet away in the garage. Thank you for helping.

 

[doghead]

Well, it sounds like an issue with your voltage regulator.

We have a few members that are well versed in this, so lets wait for one of them to post up.

 

[Speddmon]

High voltage and the inability to adjust it back down is the classic symptom of a failed output transistor on the AC voltage regulator. This is a VERY common issue, and has been covered in great detail on the board before, some searching should turn up LOTs of information for you to read

As Doghead mentioned, and you stated....never Idle the engine for a "warm-up" That is a sure way to kill the transistor. Luckily for you it's an easy fix, the transistor is about $5.00 and about 1/2 hour to change. It takes longer to get the epoxy off of the connections and the transistor than it does to actually unsolder it and change it.

 

[delvin00]

I am truly a fortunate blind rodent. Maybe when I figure out this great site a little more I can contribute more than just questions. Thank you gentlemen for your help.

 

[Isaac-1]

Like Speddmon said, classic symptoms of a bad output transistor, you may find it will work right for a few minutes when cool, then the voltage will spike. Removing the voltage regulator board from the housing is the hardest part of changing the transistor, you may want to order a spare in case you kill the replacement shipping will likely be more than the transistor (note when soldering in the new transistor hold it with a pair of pliers or similar to act as a heat sink so you don't cook it.)

Ike

p.s. note the JAN or JANX prefix on the transistor is for milspec, these cost several times the price of the standard civilian transistor and all it buys you is lot testing on an otherwise highly reliable part.

Ike