Bay Area Crack Repair [resolved]

dodossssssssss · 1478

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Offline dodossssssssss

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on: December 02, 2020, 07:20:45 AM
Does anyone know of a Bay Area audio technician that could fix my crack?

I built it a couple years ago and it was working fine except would randomly get a really loud hiss. When that happened I'd just unplug my headphones for a second and then replug them and it would go away, however, about six months ago I guess I didn't make it in time and the was a loud pop. After the pop the amp didn't work for a couple days then suddenly came back. The pop happened again a few months ago and it hasn't been able to make any noise since. I have checked resistance and everything reads correctly except the rca center pins have much too high of a resistance reading (somewhere above 50k ohms). It seems to start around the A terminals. When powered on the LED does not turn on but both of the tubes do glow. I have not been able to successfully get any voltage readings (it always reads 0 even though with chopsticks it pops all over the place, I think I'm just bad with a multimeter). If anyone has suggestions on what I could try I'm open to them but I would like to just have a professional have a go over the entire circuit if possible. Thanks.
« Last Edit: December 03, 2020, 06:58:44 AM by Paul Birkeland »



Offline Paul Birkeland

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Reply #1 on: December 02, 2020, 07:30:10 AM
I would bet one of the two black wires on your headphone jack isn't captured by solder.  I see that on at least half of the Crack kits I get in for repair.

If chopsticks make pops, you need to reheat every single joint in the amp (other than the power switch an A3/A8) and let the solder flow out properly. 

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline dodossssssssss

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Reply #2 on: December 02, 2020, 09:09:22 AM
Thank you for the response! I just attempted to reheated every joint till the solder was flowing and found that terminal 10 was not properly secured with solder so I added some to it but this hasn't fixed the issue. I also noticed some gunk (looks sort of like melted plastic) on PT-10 terminal 13. The black wires on the headphone jack are both very secure on each of the joints that they go through. The LED's still don't light up despite the tubes lighting and warming up. Could the PT-10 be blown?

Also, I realized that the resistance readings on the rca center pins are correct, my multimeter just doesn't go high enough and since they read somewhere above 50k I assume they are at the correct resistance.



Offline Paul Birkeland

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Reply #3 on: December 02, 2020, 02:20:51 PM
We see a blown power transformer about every 5 to 10 years.  If the tubes are still glowing, your power transformer isn't blown.

Could you post some photos of your build?

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline dodossssssssss

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Reply #4 on: December 02, 2020, 03:56:34 PM
I've attached the photos. If you want better pictures of any specific part please let me know.
« Last Edit: December 02, 2020, 04:00:50 PM by dodossssssssss »



Offline Paul Birkeland

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Reply #5 on: December 02, 2020, 05:08:48 PM
You need way more solder on your joints.  You also need to heat the joints longer to let the solder flow out.  Out of curiosity, what kind of solder are you using?

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline dodossssssssss

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Reply #6 on: December 02, 2020, 05:31:17 PM
Thank you! I'll get started soldering again tonight and let you know how it goes. I'm using 60/40 with rosin core. I think I got it from ace hardware back when I first built the Crack.



Offline dodossssssssss

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Reply #7 on: December 02, 2020, 06:24:25 PM
I can't thank you enough! It's working and sounds better than I remember. Thank you so much for helping me out with this! I was at my wits end trying to figure this out on my own but am ecstatic to have it working again.