Symptoms of a bad cathode bias resistor '68 bassman

[Lydian]

AC568 scheme.

I just got done changing all the caps in the doghouse and the bias capacitor. I'm still getting a weak signal from all channels. I've noticed a resistor is worn its way to reading like a plain piece of wire to ground on the outer 6l6 cathode to ground. I've taken the resistor out and still nothing once I measure it. The inner tube cathode resistor reads 149-151 or so, just fine(150 ohm 7w concrete resistor).

I'll have to wait till Monday for my electronics store to open. Could this be a solid assumption as to why I have such a weak signal? If not, what input do you guys have? If so, and since it has to be replaced regardless, what options for replacements are acceptable if I cant find a concrete resistor exactly at 150 ohm 7 watt? Would a carbon film, metal film, etc. do the trick?

Thanks comrades,
Dalton

[Sowhat]

Ahhh... yeah that might be a problem, if you could look at it on a scope it would probably look a little half wavey at best... half the wave half the power right?

Any 7 watt or greater 150 ohm resistor will work, you could use a 100 and a 50 in series, 3 50's in series, 2 300's in parallel the possibilities boggles the mind. You can even miss the value by a little and still be pretty much O.K. Of course there's nothing like having the exact specified component but sometimes that's just not possible.

[pdf64]

If the cathode of a design intended for mixed (cathode + fixed) bias is connected directly to 0V, the fixed bias may not be sufficient and the tube may be expected to run very hot.
I don't see that would make the amp's signal weak though, unless that tube has failed.
I suggest a voltage survey is done, ie Vdc at idle for all electrodes of all tubes, once a suitable bias arrangement has been restored.