Oh dear what a pity,how dashed unfortunate! Everything lights up, but there'sno change in reading when the scales are moved. There are two power transistors associated with the power supply, are there some simple tests I can do with my DMM or trusty old AVO to see if they have blown?
Cheers Tim
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Assuming the transistors are being used in a linear circuit ie not a switch mode power supply, you should measure about 600mV between the emitter and the base. Furthermore the voltage between emitter and collector would normally be more than a volt or so.
Difficult to generalise but if there is 600mV B-E and a large number of volts C-E. the device is probably not happy. If C-E is zero without B-E being 600mV, be suspicious also. If the is no voltage difference between all three terminals - it is dead. Any more than 750mV B-E forward biassed indicates a dead, or soon to be dead device.
hth
Bob
You've probably found something by now, but I just came across some stuff here that may be useful
Regards
Peter
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