Blowing HT fuse-probably rectifier tube?

[Kinkless Tretrode]

My Metroamp JTM45 just started blowing the HT fuse. I changed KT-66 sets and it worked fine for about 60 seconds and then it went again, although I didn't re-bias yet.

I just checked and it blows with all the tubes pulled, but the rectifier tube. Good chance it's the rectifier tube me thinks?

I don't have a spare rectifier tube handy nor a plug in SS rectifier. I do have an old 5Y3 around but I'm not sure that would be a good idea.

Also I'm having a hard time finding slow blow 1/2 amp fuses or 1/3 amp fuses. I can find fast blow fuses in that range. Might the fast blow fuse be an issue?

[ivan H]

Hi, yes, u should be using slow blow fuses for the HT. The initial current draw of the filter caps charging will cause fast blow fuses to blow. U can get slow blow fuses of the correct amparage from Valvestorm. Cheers