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Old 21st Aug 2014, 10:49 am   #8
sparkymike
Heptode
 
Join Date: Dec 2006
Location: Colchester, Essex, UK.
Posts: 717
Default Re: PO 12D AVO 81/1 Meter Multirange

Well today it is working up till now. yesterday it was start stop start stop for no apparent reason.
If it does it again, I can only think that it might be a deposit on the rotary switch tracks or the wipers of the switch. Can't see or think of any other reason for the problem, unless there is a minute hair in the air gap of the movement which is sometimes locking the movement. I did find that the movement spindle has loads of side play which was causing it to stick, but I managed to cure that by turning in the centre end float screw, which needed several turns. I would think that someone " got at it " in the past. I would not think it was due to natural wear on the end of the spindle.
DC volts seem about right, but AC volts are reading around 200 for 235 mains.
Ohms get fsd when probe terminal are linked on X1 and X100 but X10k only gets half fsd deflection.
Anyone any idea why so many diodes in this meter and what purpose do they serve ?
Mike.
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