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Old 7th March 2017, 01:14 AM   #1
waltroman is offline waltroman  United States
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Default Possible Power Transformer problem

I finally got around to building the second TSE board. On the previous board I ran a 10 watt resistor for R6 and it got so hot it toasted the pads and C7. On the previous board I used a second switch to power the HV supply and a main switch for everything else. I believe my wife was listening and left one of the switches on for an number of days.

That said I can leave all tubes out and get correct -volts on R30 and checking T1 through T8 all look good.

With a rectifier tube in I only get around 50 volts across R30 and I and hear a very muted snap (almost like a relay kicking in) and profound plastic/wax melting smell until I shut it down. I cannot trace the source of the heat from the board or components on the board. Filament supply for the Rectifier, output tubes and the 5842 seems good.

I cannot measure any thing across R29 and R18.

I Start my work week tomorrow and I have been at this all day so I may take awhile to do further tests. Thanks in advance for any insight.
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Old 7th March 2017, 05:56 PM   #2
w5jag is offline w5jag  United States
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Quote:
That said I can leave all tubes out and get correct -volts on R30 and checking T1 through T8 all look good.
R30 is the 130K bleeder resistor in the B+ line? I would think you should get zero at that point with no tube installed.

Quote:
With a rectifier tube in I only get around 50 volts across R30 and I and hear a very muted snap (almost like a relay kicking in) and profound plastic/wax melting smell until I shut it down.
Check value and integrity of resistor R30, and filter capacitors C4 and C5.

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Old 7th March 2017, 07:19 PM   #3
waltroman is offline waltroman  United States
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I actually get around a negative 260-275 volts across R30 with not rectifier.

I will check R30 and the c4 and c5 caps when I get home, I am reusing a 2.7uF mundorf supreme for c4 and had to run leads to it so may be suspect. I have a brand new C5 Panasonic 470uF with two 40uF oil caps added.
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Old 7th March 2017, 07:28 PM   #4
waltroman is offline waltroman  United States
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Just remembered I am running a inrush current limiter and it may be getting hot. I used to run a second limiter for the H.V. tap on the power transformer. This could be the source of the sound I am hearing.
The best place for the current limiter would probably be the H.V. tap slowing B+ from the 5U4G.
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Old 8th March 2017, 12:20 AM   #5
waltroman is offline waltroman  United States
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Still getting the ticking sound when powering up with a rectifier even after removing the current limiter
Nothing on this board shows sign of arcing or overheating.

When wiring in the led pilot lamp i accidentally brushed across the leads of the IEC outlet with a screw driver and the fuse popped but I did not give it much thought. Is it possible the 20amp on/off switch or IEC receptacle has been compromised?


I may have to get a cap tester, one that will test caps in circuit would be of great help now. R30 looks good. When I built this board I put all resistors in individual drawers of a small parts unit after testing them and tested them again before installation.

I will replace C4 with another poly cap when I get a chance.

Last edited by waltroman; 8th March 2017 at 12:27 AM.
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Old 9th March 2017, 12:05 PM   #6
waltroman is offline waltroman  United States
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Ticking is coming from the IEC receptacle, the one I popped a fuse in. I talked to one of the engineers at Edcor and wanted to rule out the Transformer and he indicated he never ran across one that had good static numbers and acted different under load.
I ordered a new C5 cap and a 130k resistor for R30.
I run the Moto Guzzi motorcycle section of a business and there is a saying about Guzzi that goes...." Moto Guzzi, making mechanics out of owners since 1921."
I fell here the same could be said about Tubelab. I say that without any malice towards Tubelab. It truly is a wonderful product.
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Old 9th March 2017, 01:42 PM   #7
w5jag is offline w5jag  United States
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At one point, I had four Jaguars, when you really did need two to make sure you had one you could drive, and was proficient enough at repairing them that other professional people were bringing their Jags to me to fix.

I bought my wife a new one in 2004, and it hasn't required any repairs at all - still has the factory battery. I would like to get her a new one, but the old one is still like new -only has about 40K miles on it. When I bought her that car, I REALLY wanted to get her a Quattroporte, but I chickened out - didn't feel up to the learning curve, after figuring out the Jaguar systems.

I still keep a 12 cylinder Jag around for when I want a couple of sets of bloody knuckles, and need to burn a gallon of premium every eleven miles or so.

Win W5JAG
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Old 9th March 2017, 08:31 PM   #8
waltroman is offline waltroman  United States
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In the late seventies there was a guy living in the same apartment comples as I that had a XKE I believe-12cyl. I left in the early AM one Sunday morning for a motorcycle ride and he was outside doing a valve adjustment. I got back shortly before dark and he was buttoning up with bloody knuckles. At least you are not alone
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Old 9th March 2017, 10:07 PM   #9
moggi1964 is offline moggi1964  England
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But Jag's are pretty

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Old 10th March 2017, 08:03 PM   #10
w5jag is offline w5jag  United States
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Indeed they are. There may never be a better looking automobile than the E Type in classic British Racing Green. Wife's sedan is BRG.

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