Carbine M3 Troubleshooting

[SteveTube]

Hello

One of my customers brings me in a Carbine M3 that, as he told me, "doesn't play any note" :lol:
The power stage is ok and I easily traced down the problem: there is no voltage on the preamp tube heaters.
There are no signs of short in the tube, the voltage regulators are all ok, but the pico fuse (F10 on the pcb if I remember well) has blown.
Since I don't have a schematic, the only thing I know about this fuse is its current rating (1A).
Does anybody know which is the voltage ratings and the type of fuse, slow-blow, fast blow or very fast blow?

 

[chevaliernoir]

I changed the pico fuse on the transistors or M6 carbine. I used fast blow, as the goal is to try to protect the transistor.

In your case, the goal is to protect the transformer, I guess, so I would consider slow blow by default, and I'm confident fast blow would make the job too