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Dana67Dart

The parts you don't add don't cause you no trouble
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When to check the rpm and dwell on the dart today.

Got out the OLD trusty Actron Automotive Analizer.


Hooked it up, started the engine and the needle was bouncing all over the place.

That's odd!

Bad points?

So i checked the battery voltage.

Same thing, so i figured the meter finally gave up the ghost.

I disconnected it and this is where it gets spooky.


THE NEEDLE KEPT MOVING.....

https://photos.app.goo.gl/28R6aV1qv5Ny6y5e8

There are no batteries!


I figure a capasitor is getting charged and powering the needle bounce.

I opened it up, the cir board looks perfect. The components look perfect.
 
Two things:

1.....Static charge on face of meter. Move your finger across the face really close without touching. If the needle moves, "it's charged." Try fogging it a few times with your breath, or wash and pat dry with window cleaner

2.. DOES IT use internal battery and has it/ they leaked? .I recently (might have posted this) had a Telco modified version of a Simpson 260, nice cosmetic shape but the batteries had leaked. To make a long story short, the batteries residual chemicals on the PC board TURNED THAT into a battery, and it will offset the needle by 1/8" or so

Actually....
3...LOL. If it was electrical you should be able to short the leads, run the switch through it's positions and it should pretty much discharge
 
1. Static is not causing it
2. No internal batteries
3. With leads shorted it still does it.


I even cleaned and tightened the contacts.

PXL_20210927_010007612.jpg
PXL_20210927_010016824.jpg
 
Is the cap an electrolytic? If they don't have a load they can act as a battery sometimes. Just exactly what does it do, and does shorting the leads or changing the switch change anything?

Actually it looks like you might have TWO electrolytics there

If you have some alligator jumper leads, try shorting first one then the other of those caps
 
. Just exactly what does it do, and does shorting the leads or changing the switch change anything
Causes the needle to bounce around when measuring voltage ( and all other functions)

shorting the leads does not effect the needle movent.

Changing switch position will sometimes make it stop, but some times make it start again.
Actually it looks like you might have TWO electrolytics there

Looks that way to me to.

If you have some alligator jumper leads, try shorting first one then the other of those caps


I'll have to try that.

I took the entire thing apart and cleaned every nook and cranny, no change.
 
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