HELP Randall RD100 6.3v fuse

[DaveWell]

Hi !

I got a randall RD100 to repair and the 6.3v fuse blow all try i give...
one 6.3 v give me nothing and the other one give me 6.1.. 6.2......
Power transo might short or blow ?

Thanks

[R.G.]

If you're reading 6+ volts from the power transformer, the transformer is probably good.

If the fuse always blows, it is likely that the wiring to the tube heaters is shorted to the chassis or signal ground somewhere in the wiring. This would also match with your reading of 0V on one side of the heaters. In most amps, these are something like 3+ volts one side, and 3+ volts on the other side.

I'd have to look up the amp schematics to tell if this is true for this amp. Do you have a link to the schematics?

[DaveWell]

Hi thanks for the infos !
Nop i didn't fid the schematic of the RD100

[Stevem]

You could have a shorted output tube .

[R.G.]

You're absolutely right - bum tube could do it as well as faulty wiring.

[DaveWell]

Hi,
I replace all Tube for Brand new one (JJ's E34L)
and the fuse still blow out .

I gonna test without all PW tube and preamp tube.

Come back soon after the test

Thanks All !

[DaveWell]

ok !
for sure with the right fuse that help... !

I clean the tube sucket, lime it, and take out the dust and it work.

Only thing thing , is the clean chnnel that lose power when play a full cord... i gonna recheck the soldering and check the Cap preamp

[DaveWell]

Thanks All 4 you Help.
The problem is slove,
The Brand new pre-amp tube as a default, i switch it and the amp is ready to Rock !

Regards


Dave