[waran2005]

Well, I gave up with the original meter, I tried to adjust the bearings and weight etc, it just doesn't want to play ball, I think it has had its day.

So yesterday I fitted a new movement and part of its housing into the original. I still have to make a bit of plastic to put in the zero needle hole as it is now adjusted from the rear and the original is missing, and also cover the old holes that were used for mounting the meter face plate.

I thought the easiest and fastest way to transplant the movement was to machine the bottom off the original case and do the same with the new Sifam movement and slot the slightly smaller Sifam housing / movement into the remains of the original case, this also allows for perfect alignet and height adjustment for the meter scale. The new taut band movement would never have fitted into the original case anyway, as much as I didn't like doing it I really didn't have any other options.

Seems to work well enough, I have test fitted and all good, calibration / linearity seems pretty reasonable, rest of the tester is way out though apart from the mA/V readings.

The roller selector / thumb wheels are a nightmare, I really have to get those removed and cleaned and working properly before even considering trying to calibrate it, there are so many dirty contacts, you have to rock each one back and fourth a dozen times before it makes a connection.

I have made a crude op amp, I've not done anything like this before, it seems to work well but is there anything I should also consider doing, incorporating into before permanently fitting it into the VCM?

Cheers all.