I did get a chance to try and measure AC signal last night. I set the function generator to 150Hz and measured the following using the Craftsman DMM:
Note the first reading is on the lead of the resistor closest to the EL34s and the second reading the other lead.
"Good" amp
R71: 29.56/9.01
R61: 29.59/13.60
R68: 18.30/3.10
R67: 18.39/2.91
PI pin 1: 13.49
PI pin 6: 9.14
"Bad" amp
R71: */11.23
R61: */12.18
R68: 18.59/2.96
R67: 18.47/2.81
PI pin 1: 12.25
PI pin 6: 11.30
The "*" indicates I could not get a reading. However I'm not sure that means there is not a signal there. I had a tough time getting a reading on pretty much all of the measurements. The meter would jump all round including "OL" pretty much every time I took a reading. If I would lift one of the leads and try again sometime it would give a steady reading. Sometimes it took multiple tries before I would get a steady reading. It seems like the DMM was "confused" easily. I did try MANY times to get the 2 readings indicated by the "*" but eventually gave up. It doesn't make sense to me to have a reading on one side of the resistor and not something on the other side.
Note the first reading is on the lead of the resistor closest to the EL34s and the second reading the other lead.
"Good" amp
R71: 29.56/9.01
R61: 29.59/13.60
R68: 18.30/3.10
R67: 18.39/2.91
PI pin 1: 13.49
PI pin 6: 9.14
"Bad" amp
R71: */11.23
R61: */12.18
R68: 18.59/2.96
R67: 18.47/2.81
PI pin 1: 12.25
PI pin 6: 11.30
The "*" indicates I could not get a reading. However I'm not sure that means there is not a signal there. I had a tough time getting a reading on pretty much all of the measurements. The meter would jump all round including "OL" pretty much every time I took a reading. If I would lift one of the leads and try again sometime it would give a steady reading. Sometimes it took multiple tries before I would get a steady reading. It seems like the DMM was "confused" easily. I did try MANY times to get the 2 readings indicated by the "*" but eventually gave up. It doesn't make sense to me to have a reading on one side of the resistor and not something on the other side.
Comment