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Re: Crab Amp Broke

Posted: Fri Jun 13, 2025 7:19 pm
by linthat22
heath wrote: Fri Jun 13, 2025 5:59 pm It could be the actual relay that changes the channel. I had one fail in a mesa years back. It failed in a way that basically shunted both channels signal to ground. I made a 4ft patch cable plugged into the fx return and on the other side it was an alligator clip and a probe. I was able to play a recorded loop through the in put and trace where the signal stopped. If that sounds deadly and beyond your comfort zone, then I recommend taking it to the tech of your choice Most decent techs are going to be able to track down your issue though.
I appreciate the heads up. I'm sure I could poke around with a probe, I'd just need to get familiar with how to trace the amp. I'm hoping that if I replace the fx loop, then it'll magically work :lol:

If not, tech city.

Re: Crab Amp Broke

Posted: Fri Jun 13, 2025 9:37 pm
by I'MAPUNKROCKERDAMNIT
linthat22 wrote: Fri Jun 13, 2025 7:17 pm
I'MAPUNKROCKERDAMNIT wrote: Fri Jun 13, 2025 6:59 pm Doses the amp still work OK without the footswitch?
Not really, not anymore anyway. Now if I do the patch cable from send to return, everything comes to life. And if I remove the patch cable, the sound fades away. Kinda weird, but the maker seems to think it's the fx loop. I guess we'll see.
One more question... what is the foot switch supposed to turn on and off?

Re: Crab Amp Broke

Posted: Fri Jun 13, 2025 10:41 pm
by linthat22
I'MAPUNKROCKERDAMNIT wrote: Fri Jun 13, 2025 9:37 pm
linthat22 wrote: Fri Jun 13, 2025 7:17 pm
I'MAPUNKROCKERDAMNIT wrote: Fri Jun 13, 2025 6:59 pm Doses the amp still work OK without the footswitch?
Not really, not anymore anyway. Now if I do the patch cable from send to return, everything comes to life. And if I remove the patch cable, the sound fades away. Kinda weird, but the maker seems to think it's the fx loop. I guess we'll see.
One more question... what is the foot switch supposed to turn on and off?

Good question, because I've yet to figure it out :lol:

Once I plugged it in and realized I had no sound, I started clicking around. The left light came on and you could hear a faint clean tone (master was sitting around 6/7 and the gain around 3), I then clicked the right button and the right light came on and there was nothing. I decided to press both together and when both lights went off, there was still zero sound. I then thought, let's activate both and see what happens and that's when the amp roared back to life. At this point, I unplugged the foot switch and the sound went away.

I think that's why the maker had me trouble shoot with the patch cable that I mentioned earlier. I also think this guy is finally realizing that buying "premium" parts off of Amazon can be a gamble.

I still love the amp, just a tad disappointed. My wife said that if it isn't working by this time next year, she wants me to buy "the Arizona amp" (Mesa) and be done with it.

Re: Crab Amp Broke

Posted: Fri Jun 13, 2025 11:36 pm
by heath
linthat22 wrote: Fri Jun 13, 2025 7:19 pm I appreciate the heads up. I'm sure I could poke around with a probe, I'd just need to get familiar with how to trace the amp. I'm hoping that if I replace the fx loop, then it'll magically work :lol:

If not, tech city.
If it roars back to life and roasts small rodents when there is a patch cable between the send and return, it's likely not a relay. I am guessing it could be a cold or broken solder joint on the switching jack of the loop, or one of the jacks in the loop itself is FUBAR'd. On many simple loops, the switching jacks are set up in a way that when nothing is plugged in, the signal passes on a direct wire to the return jack tip terminal. Instant true bypass. You can check that with a simple continuity setting on a volt meter though. One probe on the tip terminal on the send and one probe on the tip terminal of the return jack when nothing is plugged in. Are they plastic or metal jacks?

Re: Crab Amp Broke

Posted: Fri Jun 13, 2025 11:45 pm
by zozobra
Pop the chassis out and post some high resolution photos from a few angles, including a couple close ups of the footswtich jack.

Re: Crab Amp Broke

Posted: Fri Jun 13, 2025 11:53 pm
by ElDirtySanchez
linthat22 wrote: Fri Jun 13, 2025 10:41 pm

I still love the amp, just a tad disappointed. My wife said that if it isn't working by this time next year, she wants me to buy "the Arizona amp" (Mesa) and be done with it.
As an Arizona native who lives in Mesa and plays Mesa amps , I second this idea haha

Re: Crab Amp Broke

Posted: Sat Jun 14, 2025 11:10 am
by linthat22
heath wrote: Fri Jun 13, 2025 11:36 pm
linthat22 wrote: Fri Jun 13, 2025 7:19 pm I appreciate the heads up. I'm sure I could poke around with a probe, I'd just need to get familiar with how to trace the amp. I'm hoping that if I replace the fx loop, then it'll magically work :lol:

If not, tech city.
If it roars back to life and roasts small rodents when there is a patch cable between the send and return, it's likely not a relay. I am guessing it could be a cold or broken solder joint on the switching jack of the loop, or one of the jacks in the loop itself is FUBAR'd. On many simple loops, the switching jacks are set up in a way that when nothing is plugged in, the signal passes on a direct wire to the return jack tip terminal. Instant true bypass. You can check that with a simple continuity setting on a volt meter though. One probe on the tip terminal on the send and one probe on the tip terminal of the return jack when nothing is plugged in. Are they plastic or metal jacks?
I'm gonna have to pull the chassis like Zozobra and check all this, but great points. I can definitely do the continuity test, but to answer your question, the jacks seem plastic on the "nut portion" but the actual part the plug touches in the amp is metal.

Re: Crab Amp Broke

Posted: Sat Jun 14, 2025 11:11 am
by linthat22
ElDirtySanchez wrote: Fri Jun 13, 2025 11:53 pm
linthat22 wrote: Fri Jun 13, 2025 10:41 pm

I still love the amp, just a tad disappointed. My wife said that if it isn't working by this time next year, she wants me to buy "the Arizona amp" (Mesa) and be done with it.
As an Arizona native who lives in Mesa and plays Mesa amps , I second this idea haha
Agreed, might be the final solution.

Re: Crab Amp Broke

Posted: Sat Jun 14, 2025 3:39 pm
by Maddnotez
So you got the Mark 3 clone im guessing? Curious if it's passable, probably won't get one but been eyeing these crabs for a long time. This thread doesn't help though tbh lol....hope you get it working.

Re: Crab Amp Broke

Posted: Sat Jun 14, 2025 4:27 pm
by Guitarbilly
These things happen. I wouldn't write it off just because of this issue.