1959 Handwired Marshall Problem

[Loop-Master Pedals]

Wanted to see if you guys could help.

Have a 100 watt Handwired 1959 from 2009.

Was doing fine and all the sudden the sound quit and had a big, loud hum and then shortly after, there was smoke from the back.

I traced the smoke down to a blown EL34. (Had a hole burned in it between pins 2 and 3)

I re-tubed with all new EL34's.

Now all I get is a real low volume sound even when cranked. Sounds farty and fizzy.

Any clues? Thanks in advance.

[VelvetGeorge]

When an output tube shorts you also need to check the tube sockets for carbon trace left behind from the arc. Also, replace the HT fuse and measure the 1k 5w screen resistor mounted on the socket. Excess screen current before the failure will often overheat that resistor and change the value.

george

[Loop-Master Pedals]

Thanks man! I replaced the HT fuse and it came back to life.

By the way, I still have that '68 Metro 100 watter you built for me from way back in 2006.