One other thing you should do before you fire it up again with the output tubes in is to adjust the 10k bias pot for the highest negative dc voltage on pin 5 as seen on either output tube.
This will save your from frying your output tubes unknowingly.
Output and Heater Questions
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Stevem
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Re: Output and Heater Questions
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: Output and Heater Questions
Ok, here is where it stands. Switched the wires on pin 3 on the output tubes and now I am blowing main fuses??? Switched them back with the same results. Performed a continuity test and getting tones on VOM when black probe to chassis and red probe to red PT wires on the standby switch and all heater wires (black and red)...they should not be grounded, correct? Did I blow up the PT?
Re: Output and Heater Questions
give the close picture of the output stage and mark the wires what did you touch
Re: Output and Heater Questions
The schematic shows continuity to ground for those wires.nflrage wrote: ↑Sun Sep 05, 2021 9:06 pm Ok, here is where it stands. Switched the wires on pin 3 on the output tubes and now I am blowing main fuses??? Switched them back with the same results. Performed a continuity test and getting tones on VOM when black probe to chassis and red probe to red PT wires on the standby switch and all heater wires (black and red)...they should not be grounded, correct? Did I blow up the PT?
Re: Output and Heater Questions
Just swapped the wires on pins 3 (anodes)...nothing more.
Re: Output and Heater Questions
OK I do see that...now I have some serious troubleshooting to do. Any easy way to test a PT with a VOM to rule that out as toasted? I have no idea where it went south. The only issue I had was the loud tone when I took the amp off standby. Thanks guys!
Re: Output and Heater Questions
now it is clear that you have many problems in your build... you need to start from one end