Screen grid resistors Nomad HiGain

[WORMDIRT]

I've had to replace a screen grid resistor on a friends Nomad HiGain and it seems that pin 6 has been cut off the powertube sockets (el34), and the screen grid resistor just goes from pin 4 to wherever (its a rat nest). The screens were 5w 500ohm, but I replaced them with what I had on hand, 5w 820ohm.
Is this a common way to hook these things up?
Also I read that screen resistor values can range from 1k to 470ohm.
A schematic seems to be unavailable.

[xtian]

Pin 6 is unused, of course, so it doesn't matter that it's missing. In many builds you will see screen or grid resistors tied to pin 6 just as a convenient mounting point.

820R sounds find for a replacement; make sure you replace both (or all four if this is a 100 watt model?).

[WORMDIRT]

Pin 6 is unused, of course, so it doesn't matter that it's missing. In many builds you will see screen or grid resistors tied to pin 6 just as a convenient mounting point.

820R sounds find for a replacement; make sure you replace both (or all four if this is a 100 watt model?).

Thank you much. Exactly what I needed.

[WORMDIRT]

Ok, now the amp is burning the screen resistor on 1 of the output tubes.
Is this likely a tube failure, or should I look in the other direction?

[strelok]

First thing I would try is a different set of tubes and go from there.

[pdf64]

Before risking good tubes in there, best to retension the socket contacts and verify that the circuit that generates / supplies the Vg-k bias voltage are good, eg dry/bad joints, fractured components, leaky caps, badly drifted resistors.
http://billmaudio.com/wp/?page_id=171
Then use a light bulb limiter and monitor the B+ / each power tube's current when powering up.

[RWood]

Sorry for hijack but relevant.
I recently built a 1987 plexi PTP in the carcass of a Carvin power amp that had fried the circuit board under one tube socket. I reused PT, one of the two OTs, and the EL34s from the channel that did not fry.
The 1987 was overheating screen resistor which was thought to be caused by oscillation, and with my poor layout made the most sense. Voltages were good. I am currently without a scope so couldn't verify.
Long story short...After reading this post I rolled tubes and found that all 3 of the PM branded tubes that I salvaged from the Carvin overheated the resistors. (I didn't keep the one from the shorted socket)
I put in a set of EH EL34s that I pulled from a repair I recently took on and problem gone. Played wide open for 30 min. with no problem. Odd that both of the tubes from the channel that hadn't fried would be bad even though they sound great. I'm going to chalk it up to that run of PM tubes.
Thanks for the suggestion.