Think I messed the whole thing up...

Hooversham · 2253

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Offline Hooversham

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on: August 09, 2023, 05:59:07 AM
So I built the most recent Moreplay. Everything went together smoothly. All power and resistance checks were within spec. Went to check the sound and there was a noticeable lack of gain in the right channel. Took it back to bench and redid the solder joints. Checked again, no power. Realized I had redid the power plug too and had to replace it. After doing so, all the resistance and power checks were off. Rechecked all joints, couldn't see anything wrong. Then retried again and it overheated so I unplugged it and let it sit.

Now I'm at a loss. How did everything go sideways so quick?



Offline Paul Birkeland

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Reply #1 on: August 09, 2023, 06:27:49 AM
Can you post build photos?  Something like that could simply be mixing up the 100K and 10K pots.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Hooversham

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Reply #2 on: August 09, 2023, 07:09:17 AM
100%. I'll post build photos when I return home this evening.



Offline Hooversham

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Reply #3 on: August 09, 2023, 12:37:51 PM
Some pics....



Offline Paul Birkeland

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Reply #4 on: August 09, 2023, 01:37:08 PM
Then retried again and it overheated so I unplugged it and let it sit.

Can you tell me more about what exactly this means?

How are your current voltages?

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Hooversham

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Reply #5 on: August 09, 2023, 02:57:00 PM
Sorry. I replaced the plug and fuse again but it got SUPER hot.

And the voltage checks are NADA. Filaments don’t glow. Only registering 120 at points 3 and 5



Offline Paul Birkeland

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Reply #6 on: August 09, 2023, 03:35:18 PM
What got super hot?

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Hooversham

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Reply #7 on: August 09, 2023, 04:27:48 PM
The transformer.



Offline Paul Birkeland

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Reply #8 on: August 09, 2023, 05:58:36 PM
If the wires going from power transformer terminals 6 and 7 touch each other, they will cause the transformer to get hot and overheat it.

What I would suggest is to actually remove the shielded twisted pairs of wires leaving power transformer terminals 6 and 7, then redo the power transformer AC voltage checks in the manual and let us know what you find.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Hooversham

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Reply #9 on: August 10, 2023, 07:49:21 AM
Did as you suggested. Power to plug is ok. 117V.

Removed shielded wired from 7 and 8. Getting no voltage on transformer.



Offline Hooversham

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Reply #10 on: August 10, 2023, 07:55:56 AM
Sorry. 7 and 6



Offline Paul Birkeland

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Reply #11 on: August 10, 2023, 08:10:10 AM
How about between 9 and 10? Between 1 and 5? (all power transformer terminals, not terminals in the amp itself)

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Hooversham

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Reply #12 on: August 10, 2023, 10:37:02 AM
117 between 1 and 5.

Nothing between 9 and 10.



Offline Paul Birkeland

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Reply #13 on: August 10, 2023, 10:39:37 AM
You will, at minimum, need a new power transformer.  I suspect the shielded twisted pair of wiring leaving the power transformer was shorting out that winding, and that toasted your power transformer.

When you order a replacement power transformer, I would also ask for a few feet of STP wire, then redo that wiring and make it look at close to what's in the manual as possible. 

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Hooversham

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Reply #14 on: August 10, 2023, 10:44:09 AM
Thank you for your help.

I’ll try!