Hi guys...
So I've offered to try and fix a friend's guitar and I think I have the fault narrowed down...
It sounds like or even is a dodgy earth connection.
I don't believe the barrel jack's connections to be faulty since wiggling the jack around a bit doesn't produce the problem. I've checked every single solder joint including every one on the pre-amp for dry joints.
I did originally find a few strands of ground wire from the shield to the jack very close to the hot terminal and rectified it and plugged back in and thought I'd solved the problem.
However I've discovered that when I press down on the bridge I can produce the sound of a dodgy earth and pressing it again stops it ( randomly though, might take a few choice firm presses). Also if I move the lead that connects the piezo around inside the guitar a little it makes the buzzing sound. Annoyingly this is encased in shrink-wrap so I can't have a visual inspection but would you say it is a faulty piezo?
If the bridge is pressed just right and the buzzing stops the guitar works perfectly, so it doesn't seem like the actual crystals are damaged or anything. When the guitar is buzzing some audio still does make it through if this is relevant.
I've also noticed that when I touch the shrink wrap on the other end of the piezo cable (the connector going to the pre-amp) it generates an even louder earth hum and touching the casing of the pre-amp at the same time causes the hum to stop?? Also if I press the piezo and cause it to hum and touch the other end and earth myself against the pre-amp, it doesn't stop the hum.
This is a real noodle scratcher and I'd love to fix it if at all possible but I realise it's pretty hard to fix a piezo, but I'd like an expert second opinion that my diagnosis is correct.
I figure if the earth were bad anywhere on the jack then the hum would be consistent.
Any ideas please?
Thanks.
So I've offered to try and fix a friend's guitar and I think I have the fault narrowed down...
It sounds like or even is a dodgy earth connection.
I don't believe the barrel jack's connections to be faulty since wiggling the jack around a bit doesn't produce the problem. I've checked every single solder joint including every one on the pre-amp for dry joints.
I did originally find a few strands of ground wire from the shield to the jack very close to the hot terminal and rectified it and plugged back in and thought I'd solved the problem.
However I've discovered that when I press down on the bridge I can produce the sound of a dodgy earth and pressing it again stops it ( randomly though, might take a few choice firm presses). Also if I move the lead that connects the piezo around inside the guitar a little it makes the buzzing sound. Annoyingly this is encased in shrink-wrap so I can't have a visual inspection but would you say it is a faulty piezo?
If the bridge is pressed just right and the buzzing stops the guitar works perfectly, so it doesn't seem like the actual crystals are damaged or anything. When the guitar is buzzing some audio still does make it through if this is relevant.
I've also noticed that when I touch the shrink wrap on the other end of the piezo cable (the connector going to the pre-amp) it generates an even louder earth hum and touching the casing of the pre-amp at the same time causes the hum to stop?? Also if I press the piezo and cause it to hum and touch the other end and earth myself against the pre-amp, it doesn't stop the hum.
This is a real noodle scratcher and I'd love to fix it if at all possible but I realise it's pretty hard to fix a piezo, but I'd like an expert second opinion that my diagnosis is correct.
I figure if the earth were bad anywhere on the jack then the hum would be consistent.
Any ideas please?
Thanks.
