2 fuses in this one. not shown on schematic. one for heater, one for main. Heater fuse stays intact on power up, therefore tube heaters and LED pilot glows.
Little 125mA fuse blows instantly. it is connected between PT CT and ground.
checked the power transformer, checks out good.
Blows fuse with the tubes removed.
Changed the rectifier diodes because I read where that was an issue at times (common problem?).
Checked the "big" resistors (220 & 470 ohm) all good.
Checked some caps, the undesignated 100uf/350V and 33uf/350Vin bottom right corner of sch. OK
Checked C17, a 10uf/350V, because I could get to the yellow glue to cut the cap loose and remove from board. OK
I haven't yet pulled C7 & C8, because of where they are and the yellow glue holding them in.
Can I test for fuse blowing with the OT unhooked from the circuit? trying to narrow down the fault but don't understand if that's ok or not. I have been powering up with a 16 ohm dummy load.
I fixed a Fender Champ recently and hoped this "easy" circuit would also be an easy fix, but not yet.
help please, thx
Little 125mA fuse blows instantly. it is connected between PT CT and ground.
checked the power transformer, checks out good.
Blows fuse with the tubes removed.
Changed the rectifier diodes because I read where that was an issue at times (common problem?).
Checked the "big" resistors (220 & 470 ohm) all good.
Checked some caps, the undesignated 100uf/350V and 33uf/350Vin bottom right corner of sch. OK
Checked C17, a 10uf/350V, because I could get to the yellow glue to cut the cap loose and remove from board. OK
I haven't yet pulled C7 & C8, because of where they are and the yellow glue holding them in.
Can I test for fuse blowing with the OT unhooked from the circuit? trying to narrow down the fault but don't understand if that's ok or not. I have been powering up with a 16 ohm dummy load.
I fixed a Fender Champ recently and hoped this "easy" circuit would also be an easy fix, but not yet.
help please, thx
Comment