Hi all, new to the forum and electronics.
I have a guitar amp, (crate gx-140c) that I can't afford to replace. it cuts out, if i gently push on the board with a wooden object it'll cut back in. But it really hard to reproduce the problem at will. Some times jiggling one of the knobs will do it but not always. Anyway, i'm convinced with my limited knowledge that one or more of the potentiometers is bad (least i hope so because its an easy fix).
I've read quite a few articles and watched every video i can. I'm confused on a few things.
One, they say connecting an ohmmeter to the outer leads of the pot will tell you the value of the pot. and, that twisting the knob will not affect it, at least not very much. This doesn't seem to be the case. Connecting the outer leads on some of the pots shows a reading that is directly affected by how much it is turned. Just as if you were connected to the wiper and one of the outer leads. On others it has no affect. Is this bad pot? a different kind of pot? Or do i have this wrong?
2nd, I've notice the pots seem to have different characteristics. eg. one pot when i connect to the center terminal, and then connect to the right terminal, will show a smooth increase in resistance as i turn it, when i connect to the left lead, it remains at 0. On another pot it shows a smooth increase on both sides. Still, other pots seem to be backwards, when I connect to the right lead and turn the knob i get nothing, but when I connect to the left it shows a smooth increase in resistance. Are these bad, or just a different type?
I'm looking for whatever help you can offer in verifying whether these are defective or not. They don't have any useful markings on them. They have serials such as 70-104-23 9905 roc. all slightly different numbers and I come up with nothing when I search for them.
I appreciate any help you can offer. Thanks for your time.
I have a guitar amp, (crate gx-140c) that I can't afford to replace. it cuts out, if i gently push on the board with a wooden object it'll cut back in. But it really hard to reproduce the problem at will. Some times jiggling one of the knobs will do it but not always. Anyway, i'm convinced with my limited knowledge that one or more of the potentiometers is bad (least i hope so because its an easy fix).
I've read quite a few articles and watched every video i can. I'm confused on a few things.
One, they say connecting an ohmmeter to the outer leads of the pot will tell you the value of the pot. and, that twisting the knob will not affect it, at least not very much. This doesn't seem to be the case. Connecting the outer leads on some of the pots shows a reading that is directly affected by how much it is turned. Just as if you were connected to the wiper and one of the outer leads. On others it has no affect. Is this bad pot? a different kind of pot? Or do i have this wrong?
2nd, I've notice the pots seem to have different characteristics. eg. one pot when i connect to the center terminal, and then connect to the right terminal, will show a smooth increase in resistance as i turn it, when i connect to the left lead, it remains at 0. On another pot it shows a smooth increase on both sides. Still, other pots seem to be backwards, when I connect to the right lead and turn the knob i get nothing, but when I connect to the left it shows a smooth increase in resistance. Are these bad, or just a different type?
I'm looking for whatever help you can offer in verifying whether these are defective or not. They don't have any useful markings on them. They have serials such as 70-104-23 9905 roc. all slightly different numbers and I come up with nothing when I search for them.
I appreciate any help you can offer. Thanks for your time.