need help with very high B+

[mstaton]

Bought this set recently. Powers on and has sound but no HV, no Hor or vert frequency sound at all, I did discover that the 5Y3 rectifier tube was blown. No filaments. I replaced it and no change(have filaments now). I discovered the B+ was twice as high as it should be. I tested the AC voltage from the power transformer and its over 900V! Each leg to ground is over 450V! Should be 280V. Is it possible the transformer is shorted inside or is there another possibility? RCA KCS82 chassis

[N2IXK]

Originally Posted by mstaton

Bought this set recently. Powers on and has sound but no HV, no Hor or vert frequency sound at all, I did discover that the 5Y3 rectifier tube was blown. No filaments. I replaced it and no change(have filaments now). I discovered the B+ was twice as high as it should be. I tested the AC voltage from the power transformer and its over 900V! Each leg to ground is over 450V! Should be 280V. Is it possible the transformer is shorted inside or is there another possibility? RCA KCS82 chassis

Are the filament windings putting out excessive voltage, as well?

If so, it sounds like you have a partial short in the primary winding, increasing the turns ratio and producing excess voltage. The transformer will likely overheat if left powered up under these conditions.

[mstaton]

Not to mention putting higher than rated voltages on the electrolytics. Ill check the filament voltages.

[mstaton]

Turns out it's the opposite. My digital meter apparently went bad. reads 900V but actually its 9V. using a different meter now. tans must be open. Filament voltage is right on spec. If it was 900V, it would have fried something for sure.

[DaveWM]

if it has sound I doubt the trans is open.