Kawai / Teisco
4 "nuclear" Teisco pickups; 6 Rocker Switches; Sophisticated circuit.
Pictures and info 8-1-08
~~~ Circuit & Switching Logic ~~~
CLICK HERE if you don't already have the schematics page open to shuttle between.
THE PICKUPS' LEAD WIRES COLOR CODES:
The black "ground" lead is from the coil's outer winding end.
The red "hot" lead is from the coil's inner winding and also from the coil's foil shield wrap that feeds coil energy leakage back into the hot lead.
The blue lead grounds the baseplate to which the metal pickup casings attach for ground shielding of the coils.
VOLUME POTS VOLUME AND BALANCE FUNCTIONS:
WITH ALL SWITCHES ON AND IN SOLO POSITION; THE GUITAR'S VOLUME BALANCES AND TONE IS CONTROLLED TOTALLY BY THE POTS: The front and back sides of pickups volume pots act similar to Nate Daniels Danelectro Dane models in that if the front side is turned up all the way then the pot's output hot line passes to the next pot downstream, and entering the next pickup in series wiring. The stream is pickups / pots 1, 2, 3, 4. If #1 pot is all the way up it passes it's signal to the backside of pot 2. If pot 2 is also all the way up then the signal can't enter pot 2's back side so it enter's pickup 2's black hot line and goes thru pickup 2 in series entering pot 2's front side thru pickup 2's red "hot" lead. HOWEVER, if pot 2 is turned down any amount, then a comensurate portion of the signal passes thru the backside of the pot and a comensurate / proportional part of the signal passes thru pickup 2 in series through the black lead on the backside of pot 2, both joining again at the center lug output of pot 2. This same scheme passes to each pot / pickup downstream until pot 4's output sends the upstream blend to the output jack tip, which has the tone pot hooked up there in parallel for master tone.
THE ON / OFF SWITCHES FUNCTION:
FOR PICKUP 1: The swith 'OFF' position connects ground from the switch plate to pot 2's backside where pot 1's black ground line is connected to pot 2 to enter the pots' chain of front-side / back-side balancing scheme, making pickup 1 simply feed back into itself at that backside input lug on pot 2.
FOR PICKUP 2: The switch 'OFF' position connects the backside lugs of pots 2 and 3, looping pickup 2's "hot" lead out of pot 2 hooked to the backside input lug of pot 3, looping pickup 2's signal back upon it's ground lead on pot 3 backside input lug.
FOR PICKUP 3: The swith 'OFF' position does the same thing as pickup 2's 'OFF' position by connecting the backside lugs of pots 3 and 4.
FOR PICKUP 4: The switch 'OFF' position does the same thing as pickup 2 and 3's 'OFF' position by connecting pot 4's "output" center lug with pot 4's backside input lug, again looping the pickup's leads back upon themselves.
The 'ON' switch position for each pickup does nothing at all but takes the 'OFF' loops out of the circuit. The pickups are then controlled separately by their volume pot settings if the 'RYTHM' / SOLO' switch is in the 'SOLO' position. If the 'RYTHM / SOLO' switch is in the 'RYTHM' position, then the 'RYTHM' circuit is switched on; See those 'RYTHM' switchs' function below.
THE 'RYTHM / SOLO' SWITCHES FUNCTION:
Either switch bank's 'RYTHM' position connects a separate filter capacitor to each of their pair of pickups while one lug on each of the 'RYTHM' switches serves as a junction to keep intact all of the pickups' pots' front-side / back-side balancing of downstream signal flow happening as said in the pots and switching sections above.
The switch bank 3 / 4 is not grounded. There is no need for it to be. Switch bank 1 / 2 is grounded only as a convenient place for a common junction for grounds needed for some of the switches functions.
Top Views From Bass Bout angle.
And a side page:
Top Treble Bout Angles and Neck Views.
Disassembled and Layout Preparation Views.
Pickups / Electronics Harness Views.
Pickup and Rocker Switch Internal Details.
Schematic and circuits.
And side pages:
More views of electronics, Neck, Headstock and Truss Rod access.
Truss rod access screw hole repair.
Preliminary Assembly 1.
Preliminary Assembly 2.
Neck Joint screw holes refurbish.
Neck pocket gauged and planed.
Taping, masking and touch-up painting inside of cutaway horns.
Noteworthy work in reassembly & set-up.
Packing inner carton
Packing into outer carton
Work needed / suggested, work done, work I will do.