Preparing a Crack Rebuild - Seeking wisdom

edklipp · 639

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Offline edklipp

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on: December 29, 2021, 03:59:05 PM
After numerous moves my Bottlehead Crack has sadly fallen into a state of disrepair. Instead of playing whack-a-mole identifying and fixing bad solder joints I've resolved that it would be more productive and fun to disassemble and rebuild the entire unit.

As such I'm seeking some advice before I get started:

  • What replacement parts should I pre-emptively order from Bottlehead? Another thread references new Crack wire, hardware, and electronics bag. Anything I'm missing? Any details on what's in the Electronics bag?
  • It seems a common concern is damage to the power transformer. Any tips in evaluating any potential existing damage and mitigating issues during disassembly?
  • Any general advice for disassembly? Between desoldering wicks, pumps, guns etc there's a lot of potential equipment



Offline Paul Birkeland

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Reply #1 on: December 30, 2021, 05:24:37 AM
Yes, a new hardware, electronics, and wire back would be a good idea.  What's in those bags is listed in the manual.

For the power transformer, I would cut off the wires that you have soldered to it so you don't have to use as much heat from your soldering iron to remove them. 

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Doc B.

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Reply #2 on: December 30, 2021, 06:19:36 AM
It may be a common concern that the power transformer is damaged. But it is seldom the case. You can check resistance across the primary and across the secondaries to see if any are open (infinite resistance). Pull the tubes before you do so to take the heaters out of the equation.

When going through threads looking for info about where to start on a repair remember to focus on what actually ended up being the problem rather than reading too much into what the speculation of the OP was. In that vein, before I took everything apart on your amp I would be inclined to reflow every solder joint and see what the result is. That is because most threads end with "reflowed the joint at terminal X and it now works".

I would also suggest taking photos of the underside before you begin. Rebuilding rather than starting a new amp from scratch can make what you see in the manual photos and what you see on the amp as you are working enough different to cause some confusion. It may help to have an image of the original wiring of your amp to make sure you have not missed any connections in the rebuild.

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


Offline edklipp

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Reply #3 on: December 30, 2021, 06:53:51 PM
Incredible! Really appreciate the support here.

I'll get to ordering some of the new parts and I'm already looking forward to getting this thing back in working order.

Cheers,
Edwin