[Boatanchors] Gonset G76 modulation and other issues

[howard holden]

Have a G76 which was working well a few years ago, now all I get on 
modulation in the AM mode is a loud hum on the carrier. Can't pick up 
the audio anywhere. Mic is OK, all audio circuitry seems to be OK - caps 
and resistors all tested, interstage and mod trannies all show proper 
continuity including ground on the interstage center tap, and relay 
switching seems to be doing all it should.  I do show about 120V of 60Hz 
across the interstage output to the mod tubes when I key up. It isn't 
there on the high power CW mode and the signal is clean. Anyone got a 
good idea?


Also I  know Gonset's documentation isn't the swiftest. But on the 12AQ5 
clamp tube the schematic shows two 47K 2W resistors from the HV plate 
supply to the clamp plate. My unit has only one, and no signs of the 
other ever having been there. (mine reads 76K ohms so it's gotta go, but 
it has little effect on output). Question is, which is correct? I recall 
reading something a long time ago about the resistors in the clamp 
circuit but don't see anything on it these days.


Thanks,

Howie WB2AWQ