Noob Issue...No power on voltage check of new build

schw06 · 1931

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Offline schw06

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on: November 04, 2013, 06:23:56 PM
Thank you in advance for the help. I just completed the build of the Crack and I double checked connections and solder joints. All resistance levels checked were spot on and I went to check the voltage and when turning the unit on I get nothing. I checked to make sure the outlet and power cord are good and the fuse appears to be just fine. The rocker switch wasn't damaged during soldering and solder connections to the IEC are good. I'm embarrassed to ask but can't get past this step. Any advice is appreciated.



Offline Paul Birkeland

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Reply #1 on: November 04, 2013, 06:30:14 PM
Are you 100% positive you put the fuse in the correct position?

There's kind of a little storage box built into the fuse holder for a spare fuse, then a little clip below it that is where the fuse should go.

Beyond that, you can set your meter to AC volts, and measure the AC voltage between L and N on the IEC entry module to be sure you're getting power into the amp.

You can then flip the switch on and measure the AC voltage on the 0-120 terminals on the PT-3 power transformer to check that the AC voltage is making it to the power transformer.

-PB

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline sjeffrey

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Reply #2 on: November 05, 2013, 02:47:52 AM
I did the same mistake the first time I plugged it in.  "Stand back, I'm about to power this sucker on"....nothing...  :o
When you put the fuse in there should be some resistance.  That will indicate it's in the right place and not in the spare holder's place.
I hope for you sake it is just the fuse, much easier to troubleshoot and fix :)



Offline schw06

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Reply #3 on: November 05, 2013, 03:13:50 AM
Thanks for the advice. The fuse is seated correctly and I am getting 120v between the L and N. When I turn the unit on I also get 120v between the 0 and 120 on the PT-3 but when I measure the voltage between terminals 4 and 5 I am getting 0v? Help!!



Offline Doc B.

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Reply #4 on: November 05, 2013, 05:11:01 AM
Presumably you mean terminals 4 and 5 on the PT-3 and not the amp chassis. First check that the wires that come out from under the wrap covering the coil and attach to each of terminal 4 and 5 are actually connected to the solder terminals, and also that those wires are heavier than the wires coming from the coil to the other terminals on the transformer. This will verify that the wires are properly connected and that the label on the transformer is properly oriented.

Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.


Offline schw06

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Reply #5 on: November 05, 2013, 05:43:50 AM
Doc B,
   Thanks for chiming in on this. The answers to all of your questions are yes...Any other possibilities?
David



Offline Paul Birkeland

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Reply #6 on: November 05, 2013, 06:56:01 AM
Try rechecking these AC voltages with the tubes removed.

-PB

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man