Missing coil tap switch in Sho Bud 6139

[Marvin Born]

There is a coil tap circuit that uses just two wires for the switch and two wires from the pickup, plus the pickup frame as the ground.

I have a 1963 Fingertip D10, that has the original coil tap switches and rewound original pickups. The connection is wired with the coil frame to ground and the output jack, then the high winding of the pickup to the neck switch and on to the jack. The coil tap switch has one connection to ground and the other connection to the coil tap on the pickup. Yes it is a SPST switch. With the switch open you have the full coil winding. With the switch closed, the bottom part of the coil is shorted to ground. Thus you are using the upper part of the pickup for output.

The tap position is reversed from the winding connection with a SPDT switch, where you select the bottom half of the coil (with the top half floating) or the whole coil with the switch. If you are having your pickups rewound for early guitars be sure you know how they were wired originally. If you have original SPST switches, tell the rewinder.

My pickups were reworked by Harry Jackson, who wound them originally.

My guitar also has a volume control instead of a tone control.

Marvin

[Jerry Jones]

When you refer to upper and lower part of the pickup, are you referring to inner coil wind and outer coil wind?

[Marvin Born]

I was thinking in terms of a pickup drawing; a coil with a connections somewhere near the middle.

Lower means, between the ground connection and the tap on the coil. Upper was referring to the windings from the coil tap connection to the other end, in other words the fully winding. Sorry for any confusion.

Its important to know where the tap is located in relation to ground, if it not in the center of the winding.

[Ian Stynes]

Hmm - interesting. Well, I'm taking my guitar in tomorrow to get it checked out by someone who knows what he's doing. I got both types of toggle switches just in case - we'll see. Thanks for the responses!

-Ian

[Jerry Jones]

Edited so as not to confuse.

[Ian Stynes]

Thanks Jerry. Good to know.

-Ian

[Ian Stynes]

Got it wired up today. The grounding issue is gone but the technician could not get the coil tap to work. he works on 6 string guitars - he's very good at it - but doesn't see many pedal steels (if any). Basically the coil tap just turns the signal on and off - like a kill switch. Sounds good but not sure what happened exactly.
-Ian

[Kenneth Rainey]

Ian, I am the happy owner of your old Sho-Bud. The toggle has broken again, and I'm about to wire up a replacement. I'm glad I found this thread -- I'm going to see if I can get the tap working finally.

[Ron Pruter]

Ian,
Get yourself a cheap multi tester. The one Harbor Freight gives away will work fine. Set to read in the 20K Ohms range. Touch the ground lead of the p/U with the black probe and leave it there. Touch an other other wire with the red probe and note the reading. Now move the red probe to the other wire and note the reading. One reading should be about half of the other, the smaller being the "tap". An example would be 5k and 10k. On the switch, connect those two red probed wires, one to one of the end connections and the other to the other end connection. These will be the inputs of the switch. Now connect the center connection of the switch (the output) to the input of the jack. ground will be common. The end plate.
One more tip, don't go back to that luthier ever again. Good luck. RP

[John Billings]

"They get smashed easily."
And I've seen many guitars with bent upward nylon tuners and rods.

[Kenneth Rainey]

Ron, thanks for the multimeter tip. I bought that old Sho-Bud from Ian, so I'm the guy replacing the toggle this time. I'll get out the multimeter and see if I get a valid readings.

[Kenneth Rainey]

Yep, it was wired incorrectly -- that's why it acted as a kill switch rather than a tap. The ground wire was connected to one of the inputs, and both input wires appear to be soldered to the same connection.

The blue block is the broken, soon to be replaced tap. The first connection is soldered to the ground wire. The middle connection is wired to the input jack, and the third connection has both the red and white wires soldered to it.