Crate Power Resistor Question

[RWood]

This is the one I posted about in the Schematics section.

In replacing the blown 150R power resistor, should I stick with the 5 watt value of the original, or increase to a 10 watt?

Even though the 5 watt blew apart like a stick of dynamite, I am glad that it did versus remaining intact and causing further damage (to the transformers I suspect). It worked like a fuse. So I wonder if a 10 watt would be less likely to blow up, but more likely to cause damage to the other parts.

Thoughts?

[52 Bill]

In replacing the blown 150R power resistor, should I stick with the 5 watt value of the original, or increase to a 10 watt?

Well, using a resistor as a fuse isn't the best solution to any problem, but it has worked out that way for years with the typical screen resistors in Fender amps.

I don't think that the way your original 5 watt exploded is by any means typical. Normally they will crack and burn and smoke, but not explode. It's usually the e-caps that do that.

I don't think that what happened to yours happens that often, so I'd go with the 5 watt.

[RWood]

Mystery is revealing itself

Thanks Bill.

After dismantling the circuit board, which involved removing a separate board for the power tubes, there was a second 5 watt (screen) resistor burned to a crisp.

Even more telling, there was, rattling around in the 1" space between the raised octal socket and the board itself, an old octal locating pin. Odds are pretty good that the power tube that lost it's pin was inserted incorrectly, and THAT caused all the destruction.

All of this was obscured from plain view, and only after disconnecting a few dozen wires and removing a bunch of screws was I able to get to the bottom of it. Now for some replacement parts!