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John M0GLN · 25th Feb 2018, 11:27 am

The current thread regarding an Avo 8 reading high made to have another look at my Mk V with a hope of getting it going again, it's also reading high, 11.1V instead of 9.2V measuring a PP3 battery, and as you can see from the attached photo someone, honestly not me, has in the past overloaded it and nearly burnt a shunt out, it measures 0.8Ω, I've looked at the circuit and I can find 3 printed shunts, 0.04Ω, 0.36Ω and 3.6Ω, so it must be either the first or second, I can't find any reference to the shunt numbers to identify them in the manual but as it's the physically biggest shunt I assume it is the 0.04Ω, can anyone confirm that for me please? There of course might be other problems as well but I'll start with this one which is definitely damaged.

Thanks

John as well

Edit, I've perhaps wrongly assumed that it is a shunt, I'm not sure and I've just measured the Fluke and that measures 0.4Ω with its leads shorted out so the toasted copper strip might be 0.4Ω as well, I don't have any specific low resistance measuring equipment, any advice welcomed.

25th Feb 2018, 11:27 am	#1
John M0GLN Octode Join Date: Jan 2004 Location: Southport, Merseyside, UK. Posts: 1,156	Toasted Avo 8 Mk V shunt The current thread regarding an Avo 8 reading high made to have another look at my Mk V with a hope of getting it going again, it's also reading high, 11.1V instead of 9.2V measuring a PP3 battery, and as you can see from the attached photo someone, honestly not me, has in the past overloaded it and nearly burnt a shunt out, it measures 0.8Ω, I've looked at the circuit and I can find 3 printed shunts, 0.04Ω, 0.36Ω and 3.6Ω, so it must be either the first or second, I can't find any reference to the shunt numbers to identify them in the manual but as it's the physically biggest shunt I assume it is the 0.04Ω, can anyone confirm that for me please? There of course might be other problems as well but I'll start with this one which is definitely damaged. Thanks John as well Edit, I've perhaps wrongly assumed that it is a shunt, I'm not sure and I've just measured the Fluke and that measures 0.4Ω with its leads shorted out so the toasted copper strip might be 0.4Ω as well, I don't have any specific low resistance measuring equipment, any advice welcomed. Attached Thumbnails Last edited by John M0GLN; 25th Feb 2018 at 11:39 am.