MEP-003A No Output

[1958 M274]

I have a MEP-003A that I acquired from a friend. I was told it ran great and worked properly for a year or two after it was acquired surplus. Then it started having intermittent output issues. Sometimes it would work, sometimes it wouldn't with no apparent pattern or reason. Due to it's unreliability and the age of the owner, he decided it would be easier to replace it with a new propane generator and automatic transfer switch for his house. The old MEP-003A sat outside for a couple years. I don't know if the fuel cap was left loose, but there ended up being a significant amount of water and corrosion in the fuel system. I replaced the fuel tank, purged the lines, serviced the filters, and freed up a stuck check valve and plunger in the injector pump. Now it starts and runs, but I have no output at all.

I've run the set several times, always with the same results. The Hz gauge reads high and fluctuates, the current gauge reads high and fluctuates, and it indicates no voltage. As you can see in the video, flashing the field and throttling up and down does not help. Also, although I don't show it in the video, adjusting the voltage knob does not affect the indications of the gauges. I have checked the terminals with my multi-meter and verified there is zero output. After running for a while (10-15 min or more) the gauges will all eventually drop to zero reading. I have searched this forum, and the internet in general, and haven't found someone with a similar issue. Anyone have any suggestions where to start?

https://youtu.be/8V5w3p5JwMk

 

[AceHigh]

Just curious if there is any power at the convenience outlet. If so first thing I would do is get a KillAWatt meter and plug it in there, that will give you an accurate hertz reading so you can set the throttle for 60 cycle. The gauge set is notoriously inaccurate. Second suggestion is to go to the manuals and begin the trouble shooting sequence.

Hoping for good luck on it, these are great units.

 

[1958 M274]

Just curious if there is any power at the convenience outlet. If so first thing I would do is get a KillAWatt meter and plug it in there, that will give you an accurate hertz reading so you can set the throttle for 60 cycle. The gauge set is notoriously inaccurate. Second suggestion is to go to the manuals and begin the trouble shooting sequence.

Hoping for good luck on it, these are great units.

No power at the convenience outlet.

 

[glcaines]

Joe,
Have you checked the main circuit breaker on the AC output control box?

 

[jamawieb]

Your problem is more than likely the CVT and CVT1 Transformers in the distribution box. The CVT transformer sends the signal to the percentage output gauge and the CVT1 takes readings and sends signals to the generator head to send out power (in simple terms). If you look in the TM, you can troubleshoot both with a multi meter.

 

[1958 M274]

Joe,
Have you checked the main circuit breaker on the AC output control box?

I'm pretty sure it's not the main breaker causing me to not get power. If it was, it would indicate voltage, but just wouldn't be getting it at the binding posts, right?

 

[1958 M274]

Your problem is more than likely the CVT and CVT1 Transformers in the distribution box. The CVT transformer sends the signal to the percentage output gauge and the CVT1 takes readings and sends signals to the generator head to send out power (in simple terms). If you look in the TM, you can troubleshoot both with a multi meter.

Found the section that covers this in the -34. Both the CT1 and CVT1 checked ok.

 

[jamawieb]

Found the section that covers this in the -34. Both the CT1 and CVT1 checked ok.

Ok, next I would troubleshoot the exciter board, very easy to do. It is located on the back wall of the distribution box, behind CT1 and CVT1. When CVT1 sends the signal to the generator head, it actually sends it to the exciter board and the board is what sends the actual signal. You'll see a 55ohm resistor and I believe 6 diodes on the board that you will need to check.

 

[1958 M274]

Ok, next I would troubleshoot the exciter board, very easy to do. It is located on the back wall of the distribution box, behind CT1 and CVT1. When CVT1 sends the signal to the generator head, it actually sends it to the exciter board and the board is what sends the actual signal. You'll see a 55ohm resistor and I believe 6 diodes on the board that you will need to check.

I found a paragraph and drawing that appear to be what you're describing, only they call it the "Bridge Rectifier Assembly". I'm assuming that's it? It may be a few days before I have time, but I will check this part and report back. Thanks!

 

[jamawieb]

Yes, that is it.

 

[glcaines]

PM Sent