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Topic: Fender Stingmaster noise problems and schematic request |
John Groover McDuffie
From:
LA California, USA
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Posted 26 Jan 2010 7:26 pm |
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The owner of the shop I teach at has a triple neck Stringmaster in for repair. The owner is complaining of a hum or buzz. Has anyone encountered bad noise problems with these? Is there anything in particular to watch out for.
Does anyone have a schematic or wiring diagram for the Stringmaster series? I assume that the two pickups on each neck are RW/RP, and it appears that the control under the bridge cover fades out one pickup so it goes from two coils in series to single coil. Have I got that right? |
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John Groover McDuffie
From:
LA California, USA
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Lynn Oliver
From:
Redmond, Washington USA * R.I.P.
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Posted 27 Jan 2010 10:46 am
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| I know from working on mine that any time the pickup plates are not in contact with the pickup cavity shielding and the ground connections there is a bad 60Hz hum. |
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John Groover McDuffie
From:
LA California, USA
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Posted 27 Jan 2010 12:29 pm
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| What do you mean by the pickup plates? The mounting plate, or is there supposed to be a bottom plate on the pickups like on a Tele lead pickup? |
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Bob Kagy
From:
Lafayette, CO USA
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Posted 27 Jan 2010 2:03 pm
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The pickup plates are the chrome plates that the pickups are mounted in, one screw on each side of the pickups do the mounting for 2 screws/PU, total of 4 screws/neck. The screws allow height adjustment of each pickup and angle adjustment for closeness to strings. The pickup control acts as a blend control for the bridge end pickup vs the one closest to the fretboard. It allows very treble or a fuller tone.
So when Lynn is talking about pickup plates not in contact with shielding underneath he's saying that if the screws holding down the chrome plates are slightly loose, it can cause a good strong hum or buzz. But that's just one thing.
Also, the neck selector switch or buttons may cause such a noise especially if you have the pushbutton type as oppoes to toggle. The insulation in the pushbutton assembly underneath the chrome plate gets worn and can cause the hum or buzz.
You might be able to isolate the problem by pushing down on the chrome plates in case it's poor contact with shielding, or by pushing the neck selector buttons to see if the hum occurs. |
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Lynn Oliver
From:
Redmond, Washington USA * R.I.P.
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Posted 27 Jan 2010 3:34 pm
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The original shielding on mine was just aluminum foil:
I replaced it with copper foil shielding, but the tolerances are so tight between the pickups and the cavities that I had to remove the foil from around the ends of the pickups, as with the original shielding.
The neck grounds are connected by jumpers from neck to neck--there is one running from under the staple in the picture. The pickup mounting plate contacts the foil and the "ground jumper staple" and ties the grounds together.
On mine if I lift any of the mounting plates I get a loud hum, which goes away if put any part of the plate in contact with the shielding. Loose screws do not cause a problem.
The cavity below the pushbutton switches was not shielded originally, but I put foil everywhere it would fit. |
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Bob Kagy
From:
Lafayette, CO USA
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Posted 28 Jan 2010 7:43 am
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| Nice pictures Lynn. Looks like you've given John everything he needs to solve his problem. |
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