MEP-802A short/fire

[rcamacho]

Ran my 802 this afternoon for it’s monthly check. No load up to operating temperature. Upon shutdown I noticed heat and burning electrical smell coming off the unit. I disconnected the batteries and that stopped the fire.

I’ve not yet torn into it for inspection but believe the short/fire occurred in the blind compartment behind the AC phase switch.

Hmm, should be a “fun” exercise to read the TM again, teardown and inspect.



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[Light in the Dark]

Take the roof off and just LOOK before you do anything. Post up anything you find.

 

[rcamacho]

Take the roof off and just LOOK before you do anything. Post up anything you find.

Yep, thats the plan.
The unit has been working reliably for a few years now up until today


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[DieselAddict]

Has it been rodent proofed? That sounds like a classic rodent attack.

 

[rcamacho]

Has it been rodent proofed? That sounds like a classic rodent attack.

Nope. I do have mothballs behind the control panel and main compartment. It will be if it turns out to be the cause and is repairable


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[kloppk]

When I poked around back there in my new to me 802 there was evidence of past rodent damage to the wires on the big terminal block in there. Damage to the insulation had been "repaired" with what looked like calking or RTV.

 

[Chainbreaker]

That's why its good to do a monthly test run, imagine if you had gone for several months and then had a power outage and went out to start it and this had happened then!

Regardless, not a good thing to encounter but good job experiencing it now without the added pressure of a power outage situation!

 

[Ray70]

once you get the top cover off, follow the AC wires too. Some people have reported shorts to ground caused by improperly routed AC wires chaffing and shorting to the aluminum body panels.
I also had a " Parts" machine once that had this same issue, I ended up rebuilding it and luckily I saw the damage while I was assessing the possibility of rebuilding the machine.

 

[Light in the Dark]

Has it been rodent proofed? That sounds like a classic rodent attack.

That is literally the first thing I do to every machine that comes in. So many sets in civilian hands with folks completely unaware of the cutout below the engine.

 

[rcamacho]

That is literally the first thing I do to every machine that comes in. So many sets in civilian hands with folks completely unaware of the cutout below the engine.

Ill have to look at the old threads on mouse screen installation


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[Light in the Dark]

Just get some 1/4" hardware cloth and self tapping sheet metal screws (I use #10 x 1/2") and cover the large hole up. The two round drain holes below the batteries are blocked when batteries are installed.

 

[rcamacho]

Just get some 1/4" hardware cloth and self tapping sheet metal screws (I use #10 x 1/2") and cover the large hole up. The two round drain holes below the batteries are blocked when batteries are installed.

Did you install the mesh from inside the panels or outside? Pics?


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[Light in the Dark]

I install from the underside. This is an older picture of an 802 I had here.

 

[rcamacho]

Have pictures of mesh installation on side and top as well?


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[69birdman]

Have pictures of mesh installation on side and top as well?


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I did the bottom exactly as LITD did but just zip tied on intake sides, nothing on top .

 

[rcamacho]

Perfect. Thanks


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[Light in the Dark]

The top is not needed over the radiator, they cannot enter there. The side vents can be done as shown, or just more sheet metal screws (what I did on the same prior machine).

In a perfect world you will also remove the sock at wire entry, and replace with a panel with wire grip/strain relief so NOTHING can enter.

 

[rcamacho]

Initial inspection complete. No obvious rodent attack. Looks like two shorts to chassis ground induced by improper routing of power lines to output lugs. I’m very thankful that my stationary unit is properly grounded.

A2-C2 short to chassis...

Looks like I'll need replacement wires M5086/2-6-9 (81349) or fabricate replacements and re-test. I'm very surprised to not see any cable routing grommets/insulators on the output wires to the output receptacles. Is this correct/NOS or should there be better cable routing away from the panels?

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[Ray70]

Exactly what I saw on mine. Was your an original machine or Letterkenny reset?

 

[rcamacho]

Exactly what I saw on mine. Was your an original machine or Letterkenny reset?

Letterkenny reset in 2010.


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