Why did the anode resistor die?

[überfuzz]

I had an amp on my bench the other day where the anode resistor was broken. The first thing I noticed with this amp was that a bypass cap on a cathode side had lost it's mojo. In addition the stage seemed totally dead, i.e. no current/voltage. So I figure the anode resistor isn't conducting. I replaced these two components and sure enough, the amp is up and running again.

Now I wonder why the anode resistor failed. I figured that the ce-stage vent totally berserk due to the bypass cap mishap. The thing is, I can't really justify my guess. Should I check for some other iffy parts in this amp?

Cheers!

[Enzo]

Anode resistor? CAthode cap? Are we talking a tube amp? WHich one? Got a schematic?

A plate resistor can just open, age, can do it, so can excess current from something like a tube failure.


It is a real appealing idea that we can find an absolute cause for everything...but we can't. Sometimes you can determine AHA!! a shorted speaker cable caused this!!! But usually we never find out why a transistor picked NOW to blow. WHy a tube picked NOW to fail. And so on.

[überfuzz]

Anode resistor? CAthode cap? Are we talking a tube amp? WHich one? Got a schematic?

yes it's a tube amp, with a common cathode stage with a bypassed cathode resistor. I don't know much more I'm afraid... It's a Hifi-amp where one channel was dead.

Edited some details about emitter/cathode - transistor/tube.

[SoulFetish]

yes it's a tube amp, and like I said it's a common emitter stage with a bypassed emitter resistor. I don't know much more I'm afraid... It's a Hifi-amp where one channel was dead.

I'm sorry, but I find vacuum tubes with emitters to be VERY uncommon indeed, sir (bypassed or otherwise).
But first, lets make sure you're not confusing tubes with transistors. Just so we're all on the same page – with the device in question, can you see through it? or does it look like a piece of dirt with 3 little wires sticking out?

[SoulFetish]

Edited some details about emitter/cathode - transistor/tube.

Well, I was HOPING to get my first thumbs down from yldouright, like everybody else here!
But NOOOOO, apparently you can't take a joke at 5am in the morning.

[walkman]

Why did the anode resistor die?

To get to the other side!

[R.G.]

I'm sorry, but I find vacuum tubes with emitters to be VERY uncommon indeed, sir (bypassed or otherwise).

Welllll...
I guess you could say that cathodes emit electrons.