Preamp keeps on blowing fuses

[NaturalBornBoy]

My friend's CAE 3+SE preamp keeps on blowing fuses.

I've replaced the fuse twice and both times, the fuse blew instantly upon powering on.

What gives?

I know that in heads/combos, fuses constantly blowing is a sign that the power tubes are on the way out but what about preamps?

[Pepi]

Fast blow = Direct short. Powersupply probably. Diode/Bridge short ???

[nakedzen]

Does it have slow or fast blow fuses? ie. are you using the correct type?

From the manual:
100V use 1.5 amp slow blow
120V use 1.25 amp slow blow

My Mako used to blow fuses when turning on/off. Andrew told me to get higher rated fuses and it has been working just fine since. Still has the same 3 years old power tubes in it when I swapped the fuse type. ymmv.

[NaturalBornBoy]

Does it have slow or fast blow fuses? ie. are you using the correct type?

My Mako used to blow fuses when turning on/off. Andrew told me to get higher rated fuses and it has been working just fine since. Still has the same 3 years old power tubes in it when I swapped the fuse type. ymmv.

0.75amp, 250v, slow blow fuse. That's what the manual states to use.

[nakedzen]

0.75amp, 250v, slow blow fuse. That's what the manual states to use.

Is the voltage that comes from the wall really that high? If it's lower than 250V it'll increase the current and puts more strain on the fuse, I'd think. Try a fuse that's rated for 230V. 0.75 amps?

[Pepi]

Quit putting fuses in it or you will cause more damage. Take it to a tech