MEP-802 and 803 Main generator tip.

[Daybreak]

I found this info about fuse mod. It pertains to all size TQG. It calls for a fast blow fuse.

https://www.marcorsyscom.marines.mil/Portals/105/pdmeps/docs/SAFETY/SAFETYMEP-MI-2003-6115-25-28.pdf

Howdy,

You found this thread, but you jumped over here.

Military MEP generator reset information go to PDF page 29

Things get updated over time. This TM is dated 2009. It covers all the reset info, and all the fuse mods put into use for MEPS at the depot and in the field.

Start off at this sticky thread.

MEP-802A MEP-803A Filters and Parts
the 2nd post has quick links to lots of stuff you will need. The 3rd post has the links to the manuals you will need.

 

[cbisson]

I have 2 802a sets. They both have the fuse mod but neither of them has the MOV in place. This thread contains a few different links sourcing the MOV, some of which are no longer available. Can anyone tell me the correct part number or provide a link to the recommended part?

Thanks to you all.

-Craig

 

[69birdman]

I have 2 802a sets. They both have the fuse mod but neither of them has the MOV in place. This thread contains a few different links sourcing the MOV, some of which are no longer available. Can anyone tell me the correct part number or provide a link to the recommended part?

Thanks to you all.

-Craig

Metal oxide varistor #14D151K, eBay vendor Dalbani ,out of Miami. 5 for $7.95 shipped

 

[Light in the Dark]

Allied has them for 7 cents a piece, no idea what freight would be. https://www.alliedelec.com/product/bourns/mov-14d151k/70231725/ (When I bought mine here, it was free overnight shipping which they have since discontinued).

 

[cbisson]

Thank you guys.

-Craig

 

[benalco1]

Instead of ordering the MOV's I'd be happy to mail you a couple of them. I only used 1 of the 10 I purchased.
If you'd like a pair of MOV's PM me your mailing address and I'll pop them in the mail to you.

Hello kloppk,

Just purchased a military generator (802) and noticed It does not have this mod.... would you happen to have any more MOV’s You’d like to sell?

 

[kloppk]

I still have some on hand.
PM me your address and I'll pop one in the mail to you. No charge, just something I do for fellow SS members.

 

[technoid]

Hello kloppk,

Just purchased a military generator (802) and noticed It does not have this mod.... would you happen to have any more MOV’s You’d like to sell?

Benalco1, when you install the mov and are ready to run it I suggest you put the 802 under a heavy load. I have the 803 and I have used an old electric stove as a load bank. The more I run it at 75-100 percent load the better it runs. It use to blow some smoke at load but now it's clean. And I had an issue with RFI when it ran but that has stopped since the heavy loading. There was AC voltage present in the DC circuit that caused Kurt's remote start to latch the heaters. It might be still there and I have not checked it yet. Good luck with your 802. These machines are built tough.

 

[benalco1]

Benalco1, when you install the mov and are ready to run it I suggest you put the 802 under a heavy load. I have the 803 and I have used an old electric stove as a load bank. The more I run it at 75-100 percent load the better it runs. It use to blow some smoke at load but now it's clean. And I had an issue with RFI when it ran but that has stopped since the heavy loading. There was AC voltage present in the DC circuit that caused Kurt's remote start to latch the heaters. It might be still there and I have not checked it yet. Good luck with your 802. These machines are built tough.

Great - I appreciate the comments. Upon executing the MOV mod, I'll def take your advice and put it under load....

 

[mlaxton]

As I posted before I upgraded the diodes in my voltage regulator and it worked and operates as it’s suppose to. The 5408 diodes can take a 1000V hit versus the 5404 which were limited by 400V. Theoretically that’s high enough that they should never burn up. I also added the MOV for additional protection and my generator already had the fuse mod. Here are the steps.


1) Properly label and then remove the 8 wires from the voltage regulator.

2) Remove the regulator from your generator.

3) Drill out the 4 rivets on the sides and remove the cover.

4) Remove the 4 screws on the back.

5) Remove the guts from the case. Then remove the two small screws, one on each side of the metal heat sink, that connect a transistor to the heat sink.

6) Remove the 4 screws holding the heat sink to the electronic board.

7) At this point you should see 4 diodes all next to each other. You want to unsolder and replace each diode with the new 5408 diodes. BE ESPECIALLY CAREFUL TO REINSTALL THE DIODES IN THE SAME DIRECTION YOU TOOK THEM OFF!!! Match the white line on the diode to line depicted on the board.

Next to the 4 diodes is another rectangle shaped component glued down on top of the fifth diode. Carefully cut the glue and pry the component up to expose that diode. Replace it with a 5408 taking the same precautions as before.

9) Now you just have to reassemble and test it out.


Sent from my iPhone using Tapatalk

How did this VR perform after replacing the diodes?

 

[mlaxton]

So since this thread has been started has anyone the performed the MOV mod, had a VR diode go out on them?

 

[fa35jsf]

How did this VR perform after replacing the diodes?

Flawlessly. Just like it should


Sent from my iPhone using Tapatalk

 

[OldPhart]

Regarding the replacement diodes, will any of those 1000v available on Amazon work or are there specific manufacturers you would recommend avoiding?

TIA

 

[Guyfang]

If it fits in the hole, should be good.

 

[TheAlfredo]

Fuse Holder is PN: BM6031SQ it's $5-$10 and is available from Mouser, Allied, Newark, Grainger...
The Fuse is PN: FNQ-R-3 it's ~$32 and is also available from Mouser, Allied, Newark, Grainger...

The MOV (Metal Oxide Varistor) I purchased from Amazon. $5.40 for a bag of 10
http://www.amazon.com/gp/product/B0087YL63G?psc=1&redirect=true&ref_=oh_aui_detailpage_o00_s00

Instead of adding the MOV to protect the diode bridge in the regulator one may be able to replace the diode bridge in the regulator with one rated at a higher PRV (peak reverse voltage). The root cause of the failures is that the PRV rating of the stock diode bridge is too low and thus they prone to failure due to excess voltage.


Different fuse's are called out for the 802/803 mod than what's used on the 805/806 mod.

Do you have a photo of the diode bridge that should be upgraded?

 

[Guyfang]

Look in the parts TM. Or the -24 TM

 

[fa35jsf]

Do you have a photo of the diode bridge that should be upgraded?

Look at my post number 102, from 3/13/2019.

It should have everything you need including common part numbers for the diodes.

Not to be rude, but please think about wether you have enough electronic knowledge and skill before attempting this. I’d hate for you to reverse a diode and fry a genset.


Sent from my iPhone using Tapatalk

 

[kloppk]

Do you have a photo of the diode bridge that should be upgraded?

The four circled in red.

 

[Guyfang]

Ah, THAT bridge. I thought the main gen diode bridge.

 

[OldPhart]

If it fits in the hole, should be good.

TYVM-after pricing a replacement VR, stator and rotor, each of which costs in the neighborhood of what I paid for my trailer-mounted 802A with <2000 hrs on it [$550], I have concluded that the price of these 3 mods and the minimal amount of effort needed to perform all 3 will be the cheapest insurance I will ever buy-