Restoration advice for Concept II Model D with PM3

[machine_74]

I have obtained a multimeter from work! Now I just have to hook it up correctly, based on the links above.

[Citroen]

Someone (Carl? Citroen? Nomath? anyone? ) could tell you what a known good generator looks like when you probe the end of the cable while spinning flywheel. (what to set the mult-meter to, what numbers to expect as you slowly rotate the flywheel) That could tell you if the generator is bad, or point you more towards a failed PM3.

You'd need an oscilloscope to see any flywheel signal. It won't register on a multimeter because multimeters are too slow to capture it.

[machine_74]

This is what I have--got some readings but I want to make sure which setting I should be on on the dial and which plug I should be using.

Beginning to think its the PM3. I did remove the housing around the board attached near the wheel and no corrosion or any trouble there.

Of course, now I can't attach a phot of the meter, but it has 400 MA, 10A, V and COM ports on the bottom, and...a V with a tilda, a V with 2 ttildas, mV, Ohm symbol etc for dial options. Sorry I'm not an electrician, more with IT

[Tsnor]

Someone (Carl? Citroen? Nomath? anyone? ) could tell you what a known good generator looks like when you probe the end of the cable while spinning flywheel. (what to set the mult-meter to, what numbers to expect as you slowly rotate the flywheel) That could tell you if the generator is bad, or point you more towards a failed PM3.

You'd need an oscilloscope to see any flywheel signal. It won't register on a multimeter because multimeters are too slow to capture it.

This is what I was after for resistence. hope the 105 ohms from the C sensor applies to the model D generator also.

Its just a coil of wire.

Get a multimeter and measure the resistance on the plug end, it should be 105 Ohms +/- 5 Ohms. If the resistance is okay then the sensor is fine.

You need an oscilloscope to measure the Voltage, its tiny millivolt spikes each time one of the three magnets in the flywheel pass by the sensor.

Chances are the 2 wire lead/sensor is fine on a Model C, its the three wire Model D sensor that has most of the problems

For voltage, I was thinking the voltage seen on the MM would be stable at zero when the flywheel was stopped, then blip to something non-zero if the generator was working once you started spinning the wheel. The model D generator does generate enough current/voltage to power the PM5, so was thinking you'd see random jumping values (that are rarely zero) on a digital auto-ranging MM if the generator was working. (Also, I would expect to see the needle on an analog unit at least twitch again because this generator gives enough juice to power the PM5.)

That said, I don't repair or work on electronics so sometimes I'm WAY off base. The $20 generator part does fix bad cable, bad coil, etc. It just doesn't help if the PM3 died.

[Herryashley22]

I have obtained a multimeter from work! get-mobdro.com/home/

[MojoGene]

Not sure if you got this solved, but I thought I would add a suggestion.

From your description, it does not sound like a problem with the PM3. I had the same issue with my rebuild (rebuilt a 1996 Model C) and it turned out to be a problem with the bearing and axle assembly. The distance between the flywheel magnet and the pickup appears to be hyper-critical, so if the bearings and axle assembly unit are not 100% flush with the housing the distance may be ever so slightly off and the pickup will not detect the spinning magnet on the flywheel.

I suggest you uninstall the axle and bearings, clean the bearing housings meticulously, lubricate the housings with a light coating of white lithium grease and the reinstall the bearings and axle taking extra care to make sure that everything is perfectly seated and tightened.

That solved my problem.