Final Voltage Check failed

bmckay73 · 1549

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Offline bmckay73

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on: April 30, 2017, 03:05:36 PM
Hi, my final voltage test numbers are off and I was wondering if someone could help troubleshoot the problem

Here are my test numbers (and what they should be)

1: 40 (50-100)
2: 65 (170)
3: 1 (0)
4: 63 (170)
5: 16 (50-100)
6: 1 (0)
7: 47 (90-115)
8: 1 (0)
9: 18 (90-115)
10: 2 (0)

I've also re done a few joints and both my leds are lighting up.



Offline bmckay73

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Reply #1 on: April 30, 2017, 03:12:41 PM
pics
« Last Edit: April 30, 2017, 03:52:16 PM by fullheadofnothing »



Offline Paul Birkeland

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Reply #2 on: April 30, 2017, 03:38:19 PM
Here are some places to start:

1.  The green wire going to A4/5 is only suppose to have 1/2" of its jacket stripped off.  It looks like much more jacket has been stripped off.  If that wire touches any other terminals, problems will follow.  I would redo that connection.

2.  The capacitor between terminals 9 and 10 is in backwards.

3.  The solder joint at terminal 3L looks like it needs just a bit more solder.  Try to heat just the terminal strip itself, then let the solder flow into that lower hole.

4. The 220uF capacitor at 12/13 (where the 270K resistor is) looks to have one lead that isn't soldered to the terminal strip.  This will result in a noisy amp.

I am absolutely elated that you came here for help! If your voltages don't return to normal with that 100uF cap flipped around, you can try measuring the voltages without the cap in the circuit (if they straighten out after that, then the cap needs to be replaced).

Also give close inspection to those 2.49K resistors on the headphone jack.  With that cap in backwards, it becomes seriously angry and can really give one of those 2.49K resistors a beating.  One will be noticeably darker than the other if this has happened, and it may no longer measure as 2.49K.

-PB

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline bmckay73

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Reply #3 on: April 30, 2017, 04:51:17 PM
Wow thanks for the quick reply, the capacitor flipping solved my voltage problems. I'm just testing out the amp though and it does seem to be a bit noisy now. I redid the 12 and 13 terminal but am still getting a good amount of noise coming out of the amp, sort of like a buzzing sound. Any thoughts?



Offline fullheadofnothing

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Reply #4 on: April 30, 2017, 05:23:25 PM
If you raise/lower the volume does the noise level change?

Joshua Harris

I Write the Manuals That Make The Whole World Sing
Kit Packer Emeritus


Offline bmckay73

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Reply #5 on: May 01, 2017, 12:58:25 AM
Yeah, the noise gets louder and quieter. It fades away at normal listening levels but i started to notice a ticking/thumping sound at normal listening levels now too
« Last Edit: May 01, 2017, 01:38:52 AM by bmckay73 »



Offline Doc B.

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Reply #6 on: May 01, 2017, 04:56:21 AM
Is the ticking sound very steady and slow, or more random?

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


Offline bmckay73

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Reply #7 on: May 01, 2017, 06:37:59 AM
It seems more fast and steady



Offline Doc B.

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Reply #8 on: May 01, 2017, 08:01:21 AM
This could be outside interference like a cell phone or router.

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


Offline bmckay73

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Reply #9 on: May 01, 2017, 12:35:17 PM
That's what it ended up being. Thank you all, I can't believe how great this makes my hd 650s sound.