Originally posted by glebert
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The Carvin 15-10714C power transformer in the V3 does indeed have a low voltage winding and a low voltage supply, it's there on the schematic-otherwise how would you run the LEDs and the relays?
. The leads are orange and brown on the nine pin plug, goes down to a pair of 1N4007 diodes and 7805 voltage regulators on the main board. I'm in the same boat. Power transformer has no identifying marks so who knows where it came from? Carvin was no help at all.
Sourced a replacement power transformer, think it came from Lenco by way of a third party but the low voltage supply is on the fritz somewhere downstream.
Big power transformer meltdown. Cascading failure.
First, the bias control failed-the wiper went open. The amp did the japanese lantern thing because there's no HT fuse. 6A circuit breaker had failed "on" previously. Result: power transformer cooked itself, all four power tubes roasted.
Now, it's got a mains fuse and a HT fuse ala Marshall and a Marshall 22k bias pot, one of those big ones. Got good steady plate voltage and bias voltage, but nothing's happening on the low voltage rail. Diodes and regulators changed. Sheesh. This amp's a freaking albatross.
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