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Customer brings in a 2016 Ric with buzzing and hum issues. It makes a sputtering buzz sound, independent of selected pickup. Also, touching the strings or bridge is hit or miss regarding hum. I discover the buzzing noise happens in vertical playing position, but not when laying flat on the table. I notice both mute adjustment screws are missing, and I can see the springs askew inside while looking into the screw holes.
I pulled the guard and measure open between pot ground and bridge, unless I pull on the ground wire to the bridge, then I get some spurious readings. Next I pulled the bridge and found the ground wire soldered to the backing plate under the mounting rubber. It works like a pickup height adjustment, the screws thread into the backing plate with a spring in between to adjust height. So that is how they make ground to the bridge and strings on these, through the adjustment screws. The backing plate is grounded, but with the screws missing, ground was being made haphazardly through the loose springs as they vibrated and contacted the plate and the bridge depending on how they were situated.
A questionable way to make a ground IMHO. I moved the ground wire from the backing plate, stripped an inch of insulation, tinned it, and bent it at 90* so some of it was in a bridge mounting screw hole, and some if it pressed down upon by the bridge mounting foot. It makes a good connection now and problem is solved.
I have been doing this type of work for about 40 years, but sometimes something new pops up that you have never seen before. Today was that day.
I pulled the guard and measure open between pot ground and bridge, unless I pull on the ground wire to the bridge, then I get some spurious readings. Next I pulled the bridge and found the ground wire soldered to the backing plate under the mounting rubber. It works like a pickup height adjustment, the screws thread into the backing plate with a spring in between to adjust height. So that is how they make ground to the bridge and strings on these, through the adjustment screws. The backing plate is grounded, but with the screws missing, ground was being made haphazardly through the loose springs as they vibrated and contacted the plate and the bridge depending on how they were situated.
A questionable way to make a ground IMHO. I moved the ground wire from the backing plate, stripped an inch of insulation, tinned it, and bent it at 90* so some of it was in a bridge mounting screw hole, and some if it pressed down upon by the bridge mounting foot. It makes a good connection now and problem is solved.
I have been doing this type of work for about 40 years, but sometimes something new pops up that you have never seen before. Today was that day.