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toneman2121

testing...testing

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can i measure voltage in a tube amp with the speakers disconnected? power tubes removed? one tube in the right output is glowing almost as bright as a light bulb. it's a stereo amp so i believe i can compare left and right and come to some conclusion. there is a resistor that looks a bit like it was overheating but measures correct resistance, i thinking when it's on, it breaks down...possible? the amp still works for a minute then the tube starts glowing and then the amp makes random popping/crackling sounds.

 

in the attachment, the tube that;s glowing is v7 in the output section page 1. the resistor is r116 on page3.

 

thanks for looking, frank

www.gibson.com_Files_schematics_GA30RVS.pdf

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I know from experience that a resistor or even a fuse can look and measure good but be bad when it heats up.

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thanks, you guys, for responding. i'll try replacing that resistor, brazzy. and thanks for the warning, hurghanico.  ;)

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well as usual i lollipop up. all this time i've been going back to the amp every now and then. checking lollipop. of course the first thing i did was swap tubes from one position to another...same lollipop. finally decided to bring it to a well recommended tech. jim walton's his name. in the philly area. google him. hell, i thought, one more search on google, a few more checks. swap some tubes and if still no luck i'll call him today. turns out when i swapped tubes the first time i put the exact same lollipop tube back in the exact same lollipop socket. off to get a set.

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well as usual i lollipop up. all this time i've been going back to the amp every now and then. checking lollipop. of course the first thing i did was swap tubes from one position to another...same lollipop. finally decided to bring it to a well recommended tech. jim walton's his name. in the philly area. google him. hell, i thought, one more search on google, a few more checks. swap some tubes and if still no luck i'll call him today. turns out when i swapped tubes the first time i put the exact same lollipop tube back in the exact same lollipop socket. off to get a set.

 

Hate when the lollipop falls in the dirt, lol. I just replaced the tubes in my DT50 the original tubes got to the point where they would work for 10-20 minutes and then just stop glowing. My first experience with bad tubes. I guess they would heat up and something inside would lose connection shutting the heaters off. Then I would let them cool down for a long while and they would repeat that cycle for a while before they just quit all together.

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