Antique Gibson amp (30s) resistor IDs

[Gtr_tech]

I'm going rounds with a late 30s Gibson EH100 trying to eliminate a hum at the spkr fld coil. Yes it has been recapped and all the coupling caps have been replaced. I can't find a print to match this one since they revised this model every 15 mins, but all that old Gibbo stuff has strange resistor IDs on the available schems. Everything is marked with an "M" after it so they all look like megohm values, but they are not. What were they doing here?

http://www.schematicheaven.com/gibsonamps/eh100_2.pdf

If the M denotes actual K values, why is the cathode resistor on the output section sporting this "M"?

[GibsonLover]

Maybe it's for ohMMMMMMM's. Who knows. That's an odd convention that does not seem to be applied consistently within the same drawing.
I'll agree most of those M values are K vakues, and the output Rk = 200 OhMMM's.
Is the 20M after the field coil 20K or what? If it's too great of a load, that could cause hum (like increasing the current on an SE amp). 20 K should be good. Check your grounding carefully. Avoid daisy-chaining any ground connections.

[Enzo]

M=1000 so 100k is 100k.

WHy is the output tube cathode resistor labelled 200M then? A typographical error, I'd say.