This is a follow up to my previous posting about issues with my Seeburg TSU5. I've isolated the problem to C514 over heating but so far have not determined the cause. I replaced C514 & C515 and R518 that bridges their negative ends. (I tested the caps to be sure they weren't shorted & the resistor's value is good.) C514 is connected to the -400V side of the 6X4 rectifier tube. I know this is a positive ground system so I was careful to replace the caps in their proper configuration, with both pos ends soldered to ground. I've switched out the 6X4 with 3 working replacements (all from working guitar amps) but C514 continues to overheat. (I shut down the system after a few seconds but in that time C514 is warm to hot.) I can test the voltage reaching this cap if that info will help in a diagnosis. Any insight into why this cap is overheating so quickly would be appreciated. Thanks!
jerold k
Jerold that circuit is so simple at that point, there are only two things that can cause heating of those caps: Either AC being fed to them, likely to cause rapid popping. Or, the cart itself is defective or inferior to use at that voltage.
RobNYC
On Saturday, January 14, 2023, 05:42:42 PM GMT-5, Jerold Kress via Jukebox-list jukebox-list@lists.netlojix.com wrote:
This is a follow up to my previous posting about issues with my Seeburg TSU5. I've isolated the problem to C514 over heating but so far have not determined the cause. I replaced C514 & C515 and R518 that bridges their negative ends. (I tested the caps to be sure they weren't shorted & the resistor's value is good.) C514 is connected to the -400V side of the 6X4 rectifier tube. I know this is a positive ground system so I was careful to replace the caps in their proper configuration, with both pos ends soldered to ground. I've switched out the 6X4 with 3 working replacements (all from working guitar amps) but C514 continues to overheat. (I shut down the system after a few seconds but in that time C514 is warm to hot.) I can test the voltage reaching this cap if that info will help in a diagnosis. Any insight into why this cap is overheating so quickly would be appreciated. Thanks!
jerold k
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A 6X4 vacuum tube can have a cathode to filament short and "still work" for a while. The only way to be sure the 6X4 is actually in good shape is on a vacuum tube tester with a good "shorts" test circuit.
Don Resor
-----Original Message----- From: jukebox-list-bounces@lists.netlojix.com jukebox-list-bounces@lists.netlojix.com On Behalf Of Jerold Kress via Jukebox-list Sent: Saturday, January 14, 2023 2:42 PM To: jukebox-list@lists.netlojix.com Subject: [Jukebox-list] FOLLOW UP TO SEEBURG TSU5 ISSUE
This is a follow up to my previous posting about issues with my Seeburg TSU5. I've isolated the problem to C514 over heating but so far have not determined the cause. I replaced C514 & C515 and R518 that bridges their negative ends. (I tested the caps to be sure they weren't shorted & the resistor's value is good.) C514 is connected to the -400V side of the 6X4 rectifier tube. I know this is a positive ground system so I was careful to replace the caps in their proper configuration, with both pos ends soldered to ground. I've switched out the 6X4 with 3 working replacements (all from working guitar amps) but C514 continues to overheat. (I shut down the system after a few seconds but in that time C514 is warm to hot.) I can test the voltage reaching this cap if that info will help in a diagnosis. Any insight into why this cap is overheating so quickly would be appreciated. Thanks!
jerold k
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...hmmmm...seem irrational to me ...three working 6X4 ? So problem comes from a further cause ! 1) disconnect R518 and test if C is still getting hot , if yes still problem C514 or 6X4 ! if not : 2) disconnect C514 and see if then C515 is getting hot 3) disconnect R519 and PulseAmplifier ( VR501), if still heating : 4) disconnect R519 and see what happens , very very strange ..but if C514 is getting hot , why not C515 .?. Perhaps changing the 6X4 by two 1N4001 Si diodes ( eventually only for testing ) .?. Just change C514 , testing ok or not it seems to be that C , doesn't cost a leg and certainly worth testing !!!
ivan alias lordbizarre
----- Oorspronkelijk bericht ----- Van: "D. Resor via Jukebox-list" jukebox-list@lists.netlojix.com Aan: "jukebox-list" jukebox-list@lists.netlojix.com, "Jerold Kress" jerold49@yahoo.com Verzonden: Zondag 15 januari 2023 03:17:18 Onderwerp: Re: [Jukebox-list] FOLLOW UP TO SEEBURG TSU5 ISSUE
A 6X4 vacuum tube can have a cathode to filament short and "still work" for a while. The only way to be sure the 6X4 is actually in good shape is on a vacuum tube tester with a good "shorts" test circuit.
Don Resor
-----Original Message----- From: jukebox-list-bounces@lists.netlojix.com jukebox-list-bounces@lists.netlojix.com On Behalf Of Jerold Kress via Jukebox-list Sent: Saturday, January 14, 2023 2:42 PM To: jukebox-list@lists.netlojix.com Subject: [Jukebox-list] FOLLOW UP TO SEEBURG TSU5 ISSUE
This is a follow up to my previous posting about issues with my Seeburg TSU5. I've isolated the problem to C514 over heating but so far have not determined the cause. I replaced C514 & C515 and R518 that bridges their negative ends. (I tested the caps to be sure they weren't shorted & the resistor's value is good.) C514 is connected to the -400V side of the 6X4 rectifier tube. I know this is a positive ground system so I was careful to replace the caps in their proper configuration, with both pos ends soldered to ground. I've switched out the 6X4 with 3 working replacements (all from working guitar amps) but C514 continues to overheat. (I shut down the system after a few seconds but in that time C514 is warm to hot.) I can test the voltage reaching this cap if that info will help in a diagnosis. Any insight into why this cap is overheating so quickly would be appreciated. Thanks!
jerold k
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