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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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On Sun, 21 Feb 2016 13:36:49 -0000 (UTC), Cursitor Doom
wrote: snip In one of your pictures there are a couple of diodes that look messed up (V1809 and V1811) near the bridge. They are supposed to be BY208-1000 (1000v rectifiers), I can see "40" on one, maybe 1N4007? I like your thinking! But no, the one nearest the bridge is a BY208-1000 alright, the other one to the side of it is a BY134. They both tested fine out of circuit. The BY134 is a lower frequency part with 2uS recovery time and is probably unsuited to replacement of BY208-1000 in any of the snubber or conversion positions indicated on the schematic primary. It should be soft recovery, medium speed (200-600nS) avalanche-rated part with a minimum 800Vprv. I'd avoid the use of anything advertised as 'ultrafast' (ie UF4007), as this circuit may need a modest recovery time in order to reduce power loss and EMI, but they could be used temporarily in troubleshooting. RL |
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