Posted:
Sat Jan 13, 2007 3:27 pmby dcriner
I suspect that the rectifier's flashing over is causing the fuse to blow. When you plug in the audio inputs, the B+ current goes up, right? Try replacing the rectifier.
Some Chinese and Russian rectifiers seem to be more prone to flashing over. I've had good luck with JJ.
Posted:
Sun Jan 14, 2007 9:40 amby Shannon Parks
Jkington, try the following and report back.
See if the Bias Supply is Working
Go ahead and remove all the tubes, leave the RCA connectors unconnected, and then power it up. Check your negative bias supply at J6 & J21 (these are at the back rear corners of the pcb and accessible during regular operation). Make sure there is about -40V on both locations. Then check J1 & J2 then J22 & J23 at either side of the blue pots. Make sure there is about -40V there, too. Then power down.
See if the Power Tubes Can Be Biased
Add the rectifier tube, and power tubes and power up. Bias the unit up and check voltages. Let idle for 15 minutes. Reset bias voltages. Shut down.