MEP-804A White Smoke from Generator Head behind L4 Lug - No Amp or Hertz on Gauges

[kloppk]

The resistance reading is taken across the wires removed from the terminals.
Not across the terminals of A1.

Have a good evening!

 

[Ray70]

Out of curiosity, is your Hz select switch missing? Looks like the alternator fuse is missing as well.

 

[scharpestguy]

The resistance reading is taken across the wires removed from the terminals.
Not across the terminals of A1.

Have a good evening!

Ok, I checked the A1 and Terminal 1 & 3 wires. I was wondering what A1 was but finally saw the A1 in the bottom left on the blue box to the right of the Fuse Mod. For those newbies like me when you run this test just take a flat head and loosen the screw, do not remove the screw as I promise you will drop it once or even twice like I did and it will hide under the wires at the bottom. The wires have a spade connector so it can slide in and out.

The Ohms on these two wires that were disconnected from the A1 was ~35ohms. Is this good/bad? Thank you all.

 

[scharpestguy]

Out of curiosity, is your Hz select switch missing? Looks like the alternator fuse is missing as well.

Ray, it is out of the panel but still there laying down. The nut and washer are still on it but won't slide off the end so I'm thinking the end unscrews and I need to get this remounted to the panel. This was a machine I got from an auction of a private individual who was auctioning off his fabrication shop and all his military equipment he had purchased over the years so I don't know the history or why but I will get it all fixed up with your help and sharing your knowledge with me. Thank you.

 

[kloppk]

That is a good reading. Exciter winding looks good.

 

[scharpestguy]

Out of curiosity, is your Hz select switch missing? Looks like the alternator fuse is missing as well.

Ray, reading over this again you are correct that the Alternator fuse is missing. The cap or what not is missing, any idea on how to source a replacement and any ideas on which fuse should go back in?

Ok, using the manuals I found the parts diagram and it appears I need the following:

9 PAOZZ PAOZZ 81349 F03A125V30A ..FUSE, CARTRIDGE 1
10 PAOZZ PAOZZ 81349 FHN26G1 ..FUSEHOLDER, EXTRACTO 1 - ORDERED OFF EBAY

Found the fuses above in a UK Ebay listing, is there another fuse that I could use that might have a different part number?

 

[Guyfang]

I plugged the part number in the U.S. Ebay and found your UK listing, and if you go farther down, you will find some in the states. Remember, 30 Amp, 250 volt. I bet if you plugged in the NSN for the fuse, it would come up also. We need to get you up to speed using the TM's. Also, look very carefully in the control cube, for the cap and fuse. Often it is hidden behind something after falling out. More often it has been stolen.

 

[kloppk]

If you don't find the cap you can easily replace the fuse holder with a new commonly available one from many parts suppliers. A real good hardware store may have one. Needs to be rated for 30 amps 250 volts minimum.

 

[scharpestguy]

Life occurred and parts had to be ordered but here is where I stand and any / all help is greatly appreciated.

Update: I installed the new Fuse and the missing cap. I started the Generator and it gave me an Under Current light. I tested the Alternator and it was only putting out approx 5 Volts. Ordered a new alternator off ebay and just installed it with a new belt. Started the Generator and it would only stay running when I had S1 in the Start position and the Over Current light was on. After I let the switch go and it turned off I am getting no power to the gauge cluster and it won't turn over from the panel. It will turn over from the crank switch on the side of the engine.

I would guess a fuse popped if I now longer have power to the panel? I see an over speed label on the blue box. Thoughts on now power and over current? Any chance I could convince one of you to create a YouTube channel showing how and where and what to check on these things!

Thank you

 

[scharpestguy]

Life occurred and parts had to be ordered but here is where I stand and any / all help is greatly appreciated.

Update: I installed the new Fuse and the missing cap. I started the Generator and it gave me an Under Current light. I tested the Alternator and it was only putting out approx 5 Volts. Ordered a new alternator off ebay and just installed it with a new belt. Started the Generator and it would only stay running when I had S1 in the Start position and the Over Current light was on. After I let the switch go and it turned off I am getting no power to the gauge cluster and it won't turn over from the panel. It will turn over from the crank switch on the side of the engine.

I would guess a fuse popped if I now longer have power to the panel? I see an over speed label on the blue box. Thoughts on now power and over current? Any chance I could convince one of you to create a YouTube channel showing how and where and what to check on these things!

Thank you

Pictures

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[Guyfang]

Life occurred and parts had to be ordered but here is where I stand and any / all help is greatly appreciated.

Update: I installed the new Fuse and the missing cap. I started the Generator, (Did it stay running when you let S1 return to the run position?) and it gave me an Under Current light. I tested the Alternator and it was only putting out approx 5 Volts. (How did you test the alternator?) Ordered a new alternator off ebay (Are you sure its the right alternator? Are you sure its new?) and just installed it with a new belt. Started the Generator and it would only stay running when I had S1 in the Start position, (Have you checked to see if S1 is wired correctly?) and the Over Current light was on. After I let the switch go and it turned off I am getting no power to the gauge cluster and it won't turn over from the panel. (Did you accidently push in the S19? Have you tested the S-17 for 24 VDC at both sides of the switch?) It will turn over from the crank switch, (S10) on the side of the engine.

I would guess a fuse popped if I now longer have power to the panel? (No. There is no fuse that protects the 24 VDC control circuit. There IS a 7 1/2 volt circuit breaker. Its in the second picture you posted. Sometimes this CB-1 will trip, and NOT pop out. To reset it, you need to pull it out and push it back in.) I see an over speed label on the blue box. (Lets worry about starting first) Thoughts on now power and over current? Any chance I could convince one of you to create a YouTube channel showing how and where and what to check on these things!

Thank you

 

[scharpestguy]

I pulled the 7.5 fuse/reset and that did not work. The charging fuse above was blown, 250V Buss AGC 1 1/2 was in it. Would this fuse be correct?

The new alternator was wired the same as the old one.

Thank you all.

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[Guyfang]

30A Batt Charging Fuse.

Fuse NSN: 5920-00-539-6920​

So no, that is not the right fuse. Check the -24P for parts you need.

Just because you wired the new Alternator up the same way the old one was, is not reason to believe its wired right. If you did not look at the schematic, you could be wrong. Always look, never trust others work.

 

[Ray70]

You can just go to any automotive parts store and get a 30A 1/4" dia. X 1 1/4" long 250V ( standard ) automotive fuse.
Typical AGC series fuse....

 

[scharpestguy]

I put a new 30 amp fuse in. Still no power to the control panel, I need to start tracing the power and find what tripped.

Can't wait till I get this generator sorted properly and my wife might get to park in the garage again!

Thanks.

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[Guyfang]

Go to S10. Is it in the normal, (run) position? If not, place it in the correct position. If so, go to S17.

Is it pulled out? If not, pull it out.

If its pulled out, go to CB-1. Test to both terminals to see if you have 24 VDC. Got voltage?

Then go back to S17. Test to see if you have 24 VDC to both sides. What you got?

 

[Guyfang]

I put a new 30 amp fuse in. (The fuse has nothing to do with starting. It protects the charging circuit) Still no power to the control panel, I need to start tracing the power and find what tripped.

Can't wait till I get this generator sorted properly and my wife might get to park in the garage again!

Thanks.

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[Ray70]

I'm not that familiar with the 804's so I will rely on Kurt and Guy to finish my thoughts here, but if you had an alternator issue and blown fuse and now no 24V to your panel, and assuming the 804 probably uses a similar ( or identical ) diode in the 24V line feeding the control panel?
Its located near the bottom of the resistor panel in the back left corner of the control cube. Possibly called CR1 if I recall?? ( hoping Kurt of Guy can confirm? )
Might want to test that diode because a blown diode will also kill 24V power to your control panel.

 

[scharpestguy]

Ray, thank-you i will look for that diode and report back hopefully tonight.

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[kloppk]

You need to grab a meter and check for ~24 DC along the path from the batteries to S1.
Check these points in this order and let us know what you get for DC voltage.
All are suppose to have ~24 volts DC on them.
All measurement are with respect to chassis ground.
Dean Crank should be in NORMAL, Emergency OFF switch pulled OUT, CB1 Reset
1) MT4 terminal 4 MT4 in in the control cube in the back right. Big terminal
2) MT4 terminal 1 Big terminal
3) S10 Dead Crank Switch terminal 2
4) S10 Dead Crank Switch terminal 3
5) CR1 RIGHT terminal. CR1 is on the component panel on the back left of the wall behind the gauges.
6) CR1 LEFT terminal
7) S17 Emergency OFF Switch both terminals
8.) CB1 Both Terminals
9) S1 terminals 2,4,6,& 8
10) S2 terminal 2

The 24 volts goes thru a couple of connectors and terminal blocks but we'll skip those until you check the readings above to determine if you need to check them.

Here is the layout of the components to help locate CR1