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Hello,
When I purchased this amp (6G9-B) it was not working. I replaced the power transformer and gave it a cap job and it fired up. I checked the voltages and discovered they are high as it relates to the schematic. My wall outlet is measuring 120v and with a Compu-Bias I measured 426v plate voltage, 37v cathode current and 15.5v Tube dissipation watts (using a 33k bias resistor). I hooked up a variac at 117v and installed a 27k bias resistor and measured 410v, 50v and -20.5v respectively. I also swapped out the rectifier tube with one pulled from another working amp and the numbers did not change. The other work I performed on the amp: changed filter, bias and bypass caps, installed a new 3 prong cord and removed the death cap and changes a couple of resistors. I went back and checked my work for bad solder connections and didn't find any with the chop stick test. The power transformer gets very hot after leaving the amp on for awhile. FYI, the tremolo is also very weak.
Any help would be appreciated.
KB
When I purchased this amp (6G9-B) it was not working. I replaced the power transformer and gave it a cap job and it fired up. I checked the voltages and discovered they are high as it relates to the schematic. My wall outlet is measuring 120v and with a Compu-Bias I measured 426v plate voltage, 37v cathode current and 15.5v Tube dissipation watts (using a 33k bias resistor). I hooked up a variac at 117v and installed a 27k bias resistor and measured 410v, 50v and -20.5v respectively. I also swapped out the rectifier tube with one pulled from another working amp and the numbers did not change. The other work I performed on the amp: changed filter, bias and bypass caps, installed a new 3 prong cord and removed the death cap and changes a couple of resistors. I went back and checked my work for bad solder connections and didn't find any with the chop stick test. The power transformer gets very hot after leaving the amp on for awhile. FYI, the tremolo is also very weak.
Any help would be appreciated.
KB