I have a reissue Fender super reverb on the bench and it pops with a arcing type sound about every 2 to 3 minutes nearly as soon as you take it off standby.
I have been through it top to bottom and the only time it has the issue is when the PI tube is in place.
I seem to have it narrowed down to being the tube socket itself, or a PI plate coupling cap, and the socket looks fine!
Anyone want to take a stab on which one it is when I get back into it tonight?
Taking bets!
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Stevem
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Taking bets!
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: Taking bets!
So everything regarding V1-V5 has been eliminated?
Might the V6 plate resistors also be on the suspect list?
I think it's less likely to be the coupling caps to the power tube grids; surely they would be more stressed without V6 in place?
Might the V6 plate resistors also be on the suspect list?
I think it's less likely to be the coupling caps to the power tube grids; surely they would be more stressed without V6 in place?
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Re: Taking bets!
I recall experiencing something like this one time, but I don't remember exactly what it was. It was rather bizarre. Turn off the lights and observe for a spark. Where there is a sound, there is something to see. It could be the socket, it could be lead dress. It's something. If you can hear it and not see it, try making a video of it. You might need to let the camera roll for a couple of cycles. You can then mark the time and snip out those segments for closer observation.
Edit: I remember now. The socket was mounted with a screws and nuts. I ran out of 1/4" #4 screws so I used 3/8". One of the pins was arcing to the screw. Like I said, it was bizarre and I heard it long before I could see it. Look for something bare and conductive in very close proximity to one of the high voltage pins.
Edit: I remember now. The socket was mounted with a screws and nuts. I ran out of 1/4" #4 screws so I used 3/8". One of the pins was arcing to the screw. Like I said, it was bizarre and I heard it long before I could see it. Look for something bare and conductive in very close proximity to one of the high voltage pins.
Last edited by Phil_S on Mon Nov 23, 2015 7:09 pm, edited 1 time in total.
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Stevem
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Ll
Yup, v1 thru v5 is clear, it's not the PI tube and it's not the output stage, it's not the ps filters and I have up rated the PI plate load resistors to new 1 watters which I guess I need to rule those out now along with the PI caps, the tube socket, but I guess the board itself could be arcing and it's a nightmare to unhook stuff to be able to flip it and take a look at it in this amp!!!
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!
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dorrisant
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Re: Taking bets!
I vote socket.
"Education is what you're left with after you have forgotten what you have learned" - Enzo
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JazzGuitarGimp
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Re: Taking bets!
I vote conductive board....
Lou Rossi Designs
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Printed Circuit Design & Layout,
and Schematic Capture
Re: Taking bets!
Solar flares. I like long odds.
I build and repair tube amps. http://amps.monkeymatic.com
Re: Taking bets!
I had something like this in an amp once, it turned out to be the 6v6's had drifted way out of bias range. New tubes, reset bias and no problems since.
Re: Taking bets!
Is it silly to ask if you tried different power tubes?
I had an old tube amp from something or another years ago when I was a kid.
I think it had 6V6's and would pop and crackle and with the lights off, there was a light show in the chassis.
Usually it is best to replace the sockets with more modern material like a Belton Micalex.
I had an old tube amp from something or another years ago when I was a kid.
I think it had 6V6's and would pop and crackle and with the lights off, there was a light show in the chassis.
Usually it is best to replace the sockets with more modern material like a Belton Micalex.
Tom
Don't let that smoke out!
Don't let that smoke out!
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gui_tarzan
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Re: Taking bets!
xtian wrote:Solar flares. I like long odds.
--Jim
"He's like a new set of strings, he just needs to be stretched a bit."
"He's like a new set of strings, he just needs to be stretched a bit."
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Stevem
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Hh
It's not a output stage issue , I have try the amp with only one output tube in place, and swapped them using only one also.
The issue only takes place when the PI tube is in place like I posted.
I also found that in disconnecting the needed wires to toll the board over and check for arcing that I have no idea how the board is duriving its ground!
I looked over it three times and it's got ground like it should buy by what means I do not know right at this point!
It was like being in the twilight zone , so I put the amp aside till the weekend.
The issue only takes place when the PI tube is in place like I posted.
I also found that in disconnecting the needed wires to toll the board over and check for arcing that I have no idea how the board is duriving its ground!
I looked over it three times and it's got ground like it should buy by what means I do not know right at this point!
It was like being in the twilight zone , so I put the amp aside till the weekend.
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!
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Leo_Gnardo
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Re: Taking bets!
Kozmic rays! 
Maybe a wire towards ground snuck under the board. Pry up & have a look, dentist mirror & flashlight. While you have the board propped up fire up again & see what about mystery arc then. Globs of solder get in there too, often from overenthusiastic noob techs, less often from factory booboos. wire offcuts too.
Maybe a wire towards ground snuck under the board. Pry up & have a look, dentist mirror & flashlight. While you have the board propped up fire up again & see what about mystery arc then. Globs of solder get in there too, often from overenthusiastic noob techs, less often from factory booboos. wire offcuts too.
down technical blind alleys . . .
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Stevem
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Jj
No, this is a reissue circuit board type model and I have the board flipped over with nothing hooked up wire wise but the tubes , the OT, the filter bank and the all the non center tap PT wires, it's crazy!
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: Taking bets!
I had an amp in which the old crusty flux had become conductive. This created random crackling. Took me two or three tries over a few years to figure it out.
http://ampgarage.com/forum/download/file.php?id=4983
http://ampgarage.com/forum/viewtopic.php?t=5822
http://ampgarage.com/forum/download/file.php?id=4983
http://ampgarage.com/forum/viewtopic.php?t=5822
"You feel like you're floating on a football field filled with marshmallows." -Dumble
Re: Taking bets!
What if you bang on it with your fist, does it pop then? I had a Super60 that was like that only when played loud. After resoldering everything and replacing sockets to no success, I made it into a head and it was fine.
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Bryan
Bryan