HMMWV Question

[Deven534]

Hi, i got a M1097 and i have a charging problem. Batteries are good. Voltage at positive terminal on alternator is 23.89V and same thing @ the voltage regulator. My question is how do i tell if its the alternator or voltage regulator that is causing this low voltage problem? Thanks for looking

 

[TedG]

If using 60amp military generator, then adjust the output voltage to 28vdc with a voltmeter (military gauge is not accurate). On top of unit is an allen head plug. Remove and inside is a potentiometer. Use a small slot screwdriver and turn pot until you get 28vdc at the batteries. Then let charge and check again. Adjust if necessary.

*BECAREFUL OF BELTS AND PULLEYS AND LOOSE CLOTHING AND FINGERS!!!!!

 

[Deven534]

I have a 200 amp alternator in it right now with 6.2L engine

 

[Retiredwarhorses]

The 200 amp is preset at the factory,it has no user adjustments....most likely the regulator.

 

[albersondh]

The reg is solid state and not a servicable part. In the shop we use a "known good" reg for testing. 200A are newer dual voltage inductive (brush-less) if Im remembering correctly. Do you get any charging off the 12v lug? Not much that can fail on those alts except bearings and rectifier sets/plates.

Got a buddy that will let you borrow a reg for troubleshooting?

 

[Deven534]

yea i got a buddy with one. so your saying that there is no way to know if its the alternator or the voltage regulator without having a good regulator to troubleshoot with? well what if i didn't have another regulator? i wouldn't want to spend money on an alternator if its just the regulator that's faulty

 

[albersondh]

You can tell your altenator is good because you can test all the circuits (cap, pot, rectifier, stator/rotor, diodes, ect) what you cannot do (according to the TM SMR code) is de-pot the solid state reg to test/repair the circuits, and it would be news to me to find out the AGARS has this capability. To my knowledge the test for a reg is go, no-go, verified with a known good, and they are non repairable (PAFZZ, should be PAHZZ, but who assigns these codes anyways....). I bet I know a few jarheads who can fix them though

Use the known good reg to verify, chances are your reg is bad, these alts are very robust. I can pull up the 34 manual for the alt but you need to get me the NSN or pn# for the alt.

 

[xtrememotives]

Can you replace?

The reg is solid state and not a servicable part. In the shop we use a "known good" reg for testing. 200A are newer dual voltage inductive (brush-less) if Im remembering correctly. Do you get any charging off the 12v lug? Not much that can fail on those alts except bearings and rectifier sets/plates.

Got a buddy that will let you borrow a reg for troubleshooting?

Can you replace the voltage regulator? If so, any chance you know the part number?

 

[albersondh]

Can you replace the voltage regulator? If so, any chance you know the part number?

What is the NSN or pn# on the alternator? I can cross that to the NSN/pn# for the correct volt-reg.

 

[StackJ]

Respectfully, please change the post title to something that describes your problem.

 

[Action]

Don't lose the small spacers under your regulator when you pull the mounting screws out.