willysmjeeps.com

I have had to replace the 1683 bulb a few times already.

I don't recall ever having to replace a 12 volt bulb on a daily driver like that over the life of ownership of the vehicle.

What the hey?

3 reasons.

1-Excessive vibration.
2-Excessive voltage. Are you regulated to 27.5 to 28.0?
3-Bad grounds causing high resistance resulting in the lamp running hotter.

I didn't realize I was still in the Events/transportation forum when I started this post.

I'm using a solid state regulator. I've checked the output sometime in the past. I'll will recheck it again and get back.

Edited: Ok I checked the output with the engine idling faster than normal and with my fluke DVM the voltage was 28.24 volts.

You are getting high just above idle. What does it read at 45 MPH about 2500 RPM?

I'll give it another check at road speed.

Ken,

You ever consider adding a small rectangular digital volt meter in the glove box or below the dash connected to the 27 spider? This would enable you to spot electrical charging issues instantly.

I use the original regulator together with a voltmeter which was on the jeep when i bought it. I played with ther tension on the springs inside the regulator until the charging system gave 27 - 27.8 volts. before that the system gets until 29.5 volts, wihich was to high and not good for the electric components ( bulbs,the ignition module and batteries )
unrestored :


middle in the green zone is ± 27.5 volt

Erik

The old analog voltmeters were an improvement over the amp meter but still not very accurate. Not accurate enough to use for troubleshooting and adjustments. The actual ranges covered from gauge to gauge will vary.

When one considers that about 70% of all complaints about operating issues on these M series jeeps is about the electrical system then the need for a more accurate digital volt meter is very obvious. My suggestion is to install a small rectangular digital voltmeter as an on board diagnostics tool which allows you to accurately monitor your electrical system performance at all times under all operating conditions.

I connected the DVM and went for a drive. Voltage started at 28.01 and after eventually decreased to 27.55 after about 10 or 15 minutes. So hope that is still not too high

I'm not sure if there is a voltage adjustment in the regulator. I think the board is potted/sealed if I recall.
I believe the regulator is G.I. since it says Government Property on the plate.

And I also guess the 28.24 volts was building the battery back up to capacity after start up.

Installing a digital voltmeter would be a good thing.

So all in all, do you think it is operating normally?

Voltage should remain fairly steady at 2500 RPM with an air temp of 70 deg's you should pull 28.03 + or - 0.40 volts constantly. Amp charge rate should vary as the battery builds up but voltage should stay dead nuts on. Doing the arithmetic on your test figures your variance was about 0.48 which is OK and close enough to 0.40 to not be a problem.

All setting are adjustable in the mechanical regulators. See the downloads section for the appropriate pages from TM 9-1825B.

That would leave vibration and corrosion/resistance/heat as a cause.

Are the 24 volt lamps you have the correct double filament lamps?

I don't have the mechanical regulator. It's electronic, and I don't remember if it has a voltage adjustment. I do have a spare regulator that was made in Tiawan. Looks just like the G.I. regulator on the outside, It has two pots in it.
Like to get my hands on a schematic and instructions for the future.

I'll get a photo of the Tiawan model tomorrow if I don't forget.

The 1683 bulbs I have are all double filament. The sockets are clean and have anticorrosion grease in them.

Are the sockets tight? Are the light assemblies mounted tight? Are the light grounds ohm checked at 0.0 resistance?

We have a member who has rebuilt his transistor unit and has said when he can find time he'll try to get a copy of the data to us.

I have that one above in my jeep.

This is my spare regulator. The components are not labeled on the printed circuit board and neither are they labeled on the schematic you have.

That's the only schematic I have found for the Motorola and Vap Air 25 amp regulators. The resistors and capacitors are labeled with their values. The rest of the components have their industry pn's on them.

Yeah, I was meaning that the schematic doesn't have component numbers like R1, C1, D1, Q1, etc. nor is it printed on the PCB.. It's like the manufacturer wants to make it difficult for someone to trouble shoot and repair it.