Help on initial powerline voltage check [solved]

Shponglize · 1615

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Offline Shponglize

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on: September 03, 2019, 02:17:17 PM
Hello all,

Building my first ever kit and decided to jump into the SEX 3.0.  Those sales work Doc! I am currently stuck at page 28 of the manual on the first incoming powerline voltage check. 

Problem: My DMM is reading anywhere from 5-9V, nothing near 115-120V as it should.

Troubleshooting: Checked the fuse with the ohm-reader - currently shows .5Ohms so it should'nt be blown.  Tried plugging into other outlets in my house, issue is consistent.  Verified the power switch had the white-down dot (i.e. on-position).

I am guessing its a wiring issue? Attached are close-ups of my soldered connections.  I followed the instructions closely and ensured mechanical connection prior to soldering (though I am sure they could've been better, its been ~15 years).

Any help would be greatly appreciated! Thanks everyone!

Dan
« Last Edit: September 03, 2019, 07:16:54 PM by Shponglize »



Offline Paul Birkeland

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Reply #1 on: September 03, 2019, 02:21:07 PM
If you plug the meter probes straight into the wall, what do you get? 

Is the meter on HOLD by any chance? 

This is almost certainly operator error with the meter, as this test can only really fail if the fuse is bad or the meter is the issue.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Shponglize

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Reply #2 on: September 03, 2019, 03:07:34 PM
Thanks for the quick reply Paul!

Wall shows 119.5v

When I had the alligator clips on the IEC terminals, I watched it jump between 5-9v and did press HOLD to see what it maxed at, but did the measurement several times over  2 days always the same thing.



Deke609

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Reply #3 on: September 03, 2019, 03:17:41 PM
Just some shots in the dark here.


I'm guessing that you used different probes to test the mains voltage (ones with slim metal points) - maybe it's the alligator clip probes?


Failing that, maybe the fuse is in the "spare holder" position and not the active one? Although I'd expect the meter to return 0V if that were the case.

Edit: you could also attempt to rule out the power cord by unplugging it from the amp, plugging it into the wall, and test to see that the same 119.5V is passed through the cord.

cheers, Derek
« Last Edit: September 03, 2019, 03:21:05 PM by Deke609 »



Offline Paul Birkeland

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Reply #4 on: September 03, 2019, 03:29:08 PM
Failing that, maybe the fuse is in the "spare holder" position and not the active one?
This is indeed very likely.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Shponglize

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Reply #5 on: September 03, 2019, 07:16:26 PM
Solved - now showing 121.1v

I triple checked the fuse placement (matched manual) and the IEC Cable was also showing 120v.

Turns out it was the alligator clips  ??? >:(.  Using the probes solved the issue.  I was following the manual suggestion of clipping it in for safety a wee bit too carefully. ::)

Okay back to soldering.  Will post when I hit my next snag.

Thanks all!