MEP-003A Volt Meter replacement

[Landshark_3]

I have a MEP-003A that seems everything works on it other than the Volt meter. I am assuming this is a amp meter to show the voltage. That is based on the shunt resistor across the rear terminals. That small coil is burnt is half and I get no reading on the meter. Is there such a thing as a replacement for that shunt, or will I have to order a new meter and if so what would be the part number of a replacement? From what I read in the TM its part number 75-5008.

 

[Scoobyshep]

The volt meter is reading the actual voltage. Check your selector knob there are 3 phase positions and single phase positions. If the set is in 3 phase and you are using the single selection it won't work

 

[rickf]

If the resistor is burnt you will have to fix it or replace it. Do you want to keep it original or would you prefer to have a digital gauge which is much more accurate? Next question would be why did it fail?

 

[Landshark_3]

If the resistor is burnt you will have to fix it or replace it. Do you want to keep it original or would you prefer to have a digital gauge which is much more accurate? Next question would be why did it fail?

I would prefer to leave it original. Does anyone where to find the replacement resistor or the value need to replace it?

 

[Scoobyshep]

What resistor? Iirc there is line voltage to the meter

Sent from my SM-S908U using Tapatalk

 

[Guyfang]

OK, Stop. The volt meter is a volt meter and not an Amp meter. Second, the AC volt meter doesn't have a shunt resister on it as far as I can remember. Please show me a picture.

 

[Guyfang]

I am going to hang my ass out here. The few times I have seen this crop up, someone ordered a meter, and the manufacturer put a coil between the two posts, Its a shorting coil. Before installation, its supposed to be removed before hooking up the two wires. What happens when the coil is not removed? When 120 volts hit the meter, its shorts out.

 

[Landshark_3]

What resistor? Iirc there is line voltage to the meter

Sent from my SM-S908U using Tapatalk

The Coiled wire here that is burnt in half.

 

[Landshark_3]

I am going to hang my ass out here. The few times I have seen this crop up, someone ordered a meter, and the manufacturer put a coil between the two posts, Its a shorting coil. Before installation, its supposed to be removed before hooking up the two wires. What happens when the coil is not removed? When 120 volts hit the meter, its shorts out.

Picture is posted, but what you say makes perfect sense. I got to my shop just a few mins ago and looked at a MEP-002A and it has the tabs but not the coiled wire. Thank you now that you say that I have seen that comment in posts that I have been reading.

 

[Guyfang]

If you only knew, how often this has happened.

 

[rickf]

So basically it is self repairing? The shorting coil did its job and shorted and broke. (What were they thinking?) So the meter should now work if it is set correctly. Are the connections clean and tight? And are you getting voltage to those connections?

The date on that meter is 2/05, that must have been a replacement. The 00X series was out of service by them wasn't it?

 

[2Pbfeet]

I'd remove the springs (coils), if it were me. No sense in risking a short to the case...

All the best,

2Pbfeet

 

[Guyfang]

So basically it is self repairing? The shorting coil did its job, (No, the coil is there to protect the meter in transport. Static electricity is what I was told. When you order one, and it comes in, you are supposed to remove it.) and shorted and broke. (What were they thinking?) So the meter should now work if it is set correctly. (Easy way to find out. start the set up. But most of the ones I saw were shorted out) Are the connections clean and tight? And are you getting voltage to those connections?

The date on that meter is 2/05, that must have been a replacement. The 00X series was out of service by them wasn't it? (No, I saw them in service up to 2010, when I stopped contracting.)

 

[2Pbfeet]

As @Guyfang wrote, it doesn't take much to short out this style voltmeter, at least in my experience. The wires in the coil are very, very thin. Although I was told a slightly different story that the movement of the needle alone, e.g. in transport, could generate enough voltage to short them out. I never put it to the test, but having taken a couple apart, I can easily believe it. Regardless, probably toast now, but if it isn't, I would still remove the springs.

All the best,

2Pbfeet

 

[Ray70]

I am going to hang my ass out here. The few times I have seen this crop up, someone ordered a meter, and the manufacturer put a coil between the two posts, Its a shorting coil. Before installation, its supposed to be removed before hooking up the two wires. What happens when the coil is not removed? When 120 volts hit the meter, its shorts out.

Only once I saw this on the volt meter on an 803. I couldn't figure out why in the world there was a wire across the studs.... Now I understand.

 

[rickf]

Sounds like some military contract spec writer "Doing his job". In other words, make it ten times more expensive and complicated then it has to be.

 

[Landshark_3]

To all thanks for the comments and input. I got the unit put back together, removed the pieces of coil that were left and fired it up. Runs like a champ I did a thermal scan of the cylinders and exhaust ports to make sure everything was running at the same temperature everything seems to be operating as it should. Also the volt meter does work and is right on with my Fluke meter.

Thanks again.

 

[Triple Jim]

No, the coil is there to protect the meter in transport. Static electricity is what I was told.

The short is there to mechanically protect the movement from shock during transport. Shorting the terminals prevents the meter's movement from slamming around. If you want to see what I mean, take an uninstalled meter, and while watching the needle, jostle it around and see how much you can make the needle move. Then short the terminals and do it again. With the short, there will be only small, damped movements of the needle no matter how much you shake it.

This is not a military thing... it's very common for mechanical meters to be shipped this way if they're not installed in equipment.