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I own this Crate amp, and at a rehearsal, I was playing normally with it, and suddenly it started stuttering and after a few seconds, went completely silent.
Later I took it home and opened to see if I could spot some damage.
Saw a lot of oxidization around a specific IC, proceeded to clean that with isopropyl alcohol and a toothbrush.
After thorough cleaning I turned it on to test it.
The amp appeared silent, except I could hear a very faint hum, I touched the speakers with my ear, and played my guitar, and I could hear the guitar.
So, I tested all the amp's controls, and all of them worked fine, except without any volume at all, so I figured that only the power amp has gone dead, and that IC was part of it.
I then proceeded on to replace that IC, I tried removing it as carefully as possible, but the corrosion destroyed a few of the board's trails, so I had to replace those trails with some wires.
I searched high and low for a GT212 schematic, but could only find the GTX212 schematic.
I compared the schematic to my board, and did not spot any difference, it's completely the same board, so I used this schematic as reference for re-creating the broken trails.
Replaced the IC with a socket, so if the new IC would happen to die, I could easily replace it.
After all my repairs were done, I went to test it again, and nothing changed, still no volume.
At this point I gave it some thought and realized that, if the oxidization made it short circuit, delivering current to the signal feed, then all the ICs would be dead, and all the transistors could be dead, and maybe even some capacitors.
So, my question is, could that have happened? Can I assume all the ICs and transistors are dead and replace everything? Or narrow it down to the part of the circuit that could have died (the power amp)?
The IC after it has been replaced:
And the trails replaced by wires, not the best soldering work, but I just wanted to do a quick fx and test the thing.
I'm attaching the schematic as well.
Later I took it home and opened to see if I could spot some damage.
Saw a lot of oxidization around a specific IC, proceeded to clean that with isopropyl alcohol and a toothbrush.
After thorough cleaning I turned it on to test it.
The amp appeared silent, except I could hear a very faint hum, I touched the speakers with my ear, and played my guitar, and I could hear the guitar.
So, I tested all the amp's controls, and all of them worked fine, except without any volume at all, so I figured that only the power amp has gone dead, and that IC was part of it.
I then proceeded on to replace that IC, I tried removing it as carefully as possible, but the corrosion destroyed a few of the board's trails, so I had to replace those trails with some wires.
I searched high and low for a GT212 schematic, but could only find the GTX212 schematic.
I compared the schematic to my board, and did not spot any difference, it's completely the same board, so I used this schematic as reference for re-creating the broken trails.
Replaced the IC with a socket, so if the new IC would happen to die, I could easily replace it.
After all my repairs were done, I went to test it again, and nothing changed, still no volume.
At this point I gave it some thought and realized that, if the oxidization made it short circuit, delivering current to the signal feed, then all the ICs would be dead, and all the transistors could be dead, and maybe even some capacitors.
So, my question is, could that have happened? Can I assume all the ICs and transistors are dead and replace everything? Or narrow it down to the part of the circuit that could have died (the power amp)?
The IC after it has been replaced:
And the trails replaced by wires, not the best soldering work, but I just wanted to do a quick fx and test the thing.
I'm attaching the schematic as well.
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