Dude like okay, I got this B1-RE 300 watt head from Ebay from an online music site. I got it... and I noticed that the fan doesnt turn on. I looked inside of it and the fan is hooked up... would you think its something wrong with the circuit board? : / Idk but like.. Im scared it's going to overheat. I've played it at a few shows and like... idk whether the heat is just from playing, or it's being pushed a bit too far.. help. : (
the fan is prolly jsut burned up. replace it.

take a voltage measurement at the points where the fan is connected to the circuit board first to make sure it's actually getting the right voltage. if it is, the fan is dead.
Quote by 09phillt
take it to a guitar shop... duh?

GTFO my GB&C. If he's asking here, he wants to do it himself, not have some smartass tell him to take it to a shop.

TS, follow what Jim said, then post here again if you need further help
R.I.P. Les Paul, 1915-2009

A man chooses, a slave obeys.
The fan could be operated via a thermal sensor. E.g. a power amplifier IC has a heatsink which helps it cool down. A thermal sensor is hooked up to this heatsink, and the other end is connected to the fan controller circuitry. When the temperature rises to a certain level, the fan kicks in to help dissipate the heat out of the head.

This is a common method used in computer power supplies and audio amplifier equipment.

Check the heads manual if it says anything about the fan.

EDIT: Just checked the manual. It says the fan is thermally operated and variable speed. Don't know if it's supposed to be off. Maybe you could send Ampeg an e-mail about it? The head does have a protection relay plus the required circuitry to prevent overheating, though.
Last edited by NukaCola at Nov 21, 2009,
never thought of that. it could be a bad thermistor preventing the fan from coming on or w/e. maybe it gets too hot and the fan should come on, but the thermistor might be bad and not activating the fan.