MEP804A will crank second then over speed fault occurs

[Redbush]

I am trying to get a Mep804a running with 108 hours, when I first got the generator it would crank but not start, I discovered the MPU missing and replaced it (nsn 6695-01-367-9723,88-21061) and adjusted to 2.88acv at A5 ( woodward gov control )
Now generator will crank for a second then The overspeed fault light goes on and generator stops.
When I turn S7( battle short ) On the gen set would crank for a sec then the under voltage fault light goes on and gen set stops
I’ve checked all relays they seem to be working with good connections
I tried using overspeed reset, didn’t seem to do anything
Gonna dive back in to the -10 TM and -24 TM trouble shooting Section and make sure I didn’t miss anything
Any help much appreciated

 

[robertsears1]

Make sure to hold S1 (start switch) around 10 seconds after it starts, won’t hurt anything. If you let go the instant it catches, strange things can happen. These gensets start different than any other thing I have ever cranked. Follow the instructions inside the control flap exactly.

 

[Redbush]

I turn s1 and hold 10 sec, generator will crank for split second then the engine stop overspeed light goes on, generator stops and will not crank .... also fallowed flap instructions and TM 9-6115-643-10 troubleshooting section

 

[Guyfang]

Pull the plug on the fault indicator. Then try and start the set.

 

[Redbush]

Pull the plug on the fault indicator. Then try and start the set.

I discontented plug on fault indicators ( box with fault light )
I turn s1, set cranks for split second then stops
Reconnected plug

Tried to start set again same thing overspeed lights up set cranks for one second stops
Tried to start with battleshort switch on, set will crank for a second then stop with now under voltage and oil pressure fault lights on.... some times they take turns being on and off

 

[Redbush]

Update something different is happening now after unplugging the fault indicator
When I try start the set with battle short on it no longer cranks but under voltage and low oil shutdown fault lights go on
................umm maybe I’ve lost my marbles on this one but I thought the battle short bypassed that stuff ??? .....
I’ve pulled overspeed relay, and that stops overspeed Fault from occurring but then the under voltage fault light happens instead ...

 

[Guyfang]

You can not start a TQG with the S7 turned on.

 

[Redbush]

You can not start a TQG with the S7 turned on.

... thanks I’ll remember that

 

[jmenende]

I had another mep giving me undervoltage errors constantly and if I remember correctly, it was a faulty power potential transformer. Thats the one located on the top right access panel where the lug reconnection board is. Its the one on the back right hand side. Its a pain to remove and test. Gonna have to remove the front panel.

Regarding the overspeed problem. I would remove it again and make sure you did not shave the tip off when it was first adjusted. Then I would adjust till the voltage showed 2.3vac. Test it directly on the mag pickup connector while using the dead crank to turn the unit over.

 

[Redbush]

Will inspect MPU and readjust to 2.3vac direct will update when completed
As for the power potential transformer I shall begin my investigation

 

[Redbush]

I’m back ... removed, inspected MPU ( no damage)
Reinstalled MPU and adjusted to now 2.3vac direct
Turn s1, set will crank for split second and stop. overspeed fault indicator illuminated .
I found the power potential transformer but haven’t tested yet ... I bet that’s the under voltage problem so I going to keep cussing the set out till I figure the overspeed fault
??? Could it be brain damage or a badly adjusted not sure if that a thing that happens with these???

 

[Guyfang]

I am trying to get a Mep804a running with 108 hours, when I first got the generator it would crank but not start, I discovered the MPU missing and replaced it (nsn 6695-01-367-9723,88-21061) and adjusted to 2.88acv at A5 ( woodward gov control )
Now generator will crank for a second then The overspeed fault light goes on and generator stops.
When I turn S7( battle short ) On the gen set would crank for a sec then the under voltage fault light goes on and gen set stops
I’ve checked all relays (How did you check them?) they seem to be working with good connections
I tried using overspeed reset, didn’t seem to do anything
Gonna dive back in to the -10 TM and -24 TM trouble shooting Section and make sure I didn’t miss anything
Any help much appreciated

Open to see comment.

 

[Redbush]

Open to see comment.

I removed, inspected and used a vault meter to test the relay and its plug ....... I think I fallowed some instructions I found on another post.
Any tips or tricks on testing the relays would be much appreciated

 

[Guyfang]

Is this what your control cube looks like? On the left side, the fifth "Relay" down. It has a button on it? And not look just like all the other "relays"?

 

[Redbush]

confirmed. Control cube look different than the rest and has button ( try’s to post pic but having problem )