S.E.X. 3 Build (pre-C4S) Blowing Fuses

burgerbassist · 2140

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Offline burgerbassist

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on: September 25, 2023, 08:02:39 AM
Hi All,

I purchased a S.E.X. 3 kit a while back and the build went swimmingly through the "Glow Test" on p.39 (tubes turned on as expected).  Then, I finished up the amp, passed resistance checks, and when I went and plugged the amp into the wall to do voltage checks it immediately fried the power fuse.

I've visually inspected and can't see anything that really sticks out to me as problematic - is there anywhere specific anyone would recommend starting to investigate power fuses blowing immediately upon power-up?

Thanks,
Dan



Offline Paul Birkeland

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Reply #1 on: September 25, 2023, 08:13:07 AM
Posting photos of your build would be the best way to start troubleshooting this.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline burgerbassist

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Reply #2 on: September 26, 2023, 06:23:21 PM
Here you go!  Let me know if there's anything you'd like to see closer.

Thanks!



Offline Paul Birkeland

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Reply #3 on: September 27, 2023, 07:31:52 AM
I'd like to see a shot of the UF4007 diodes and how they are connected.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline burgerbassist

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Reply #4 on: September 27, 2023, 08:02:46 AM
It looks like that's where the issue is - I accidentally soldered to 36U and 34L instead of 36U and 33L.

After I get it fixed, do you think this mistake likely has the potential to have caused larger issues that I may have to track down and fix?



Offline Paul Birkeland

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Reply #5 on: September 27, 2023, 01:34:30 PM
No, thankfully that kind of mistake will just blow the fuse and the rest of the amp will be OK.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline burgerbassist

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Reply #6 on: September 28, 2023, 07:46:33 AM
Perfect.  Well, thank you for the help!