[murf]

Hi guy's,
I made the mistake of buying a 1941 12S568 with crumbling wire up the hind in.
Main question is how the tone control is wired?
Wires are totally toast on this thing.
Can't hardly even tell l what the colors were. The coating is gone and what little bit is left is so discolored and faded its hard to tell one from the other.
Looks like we are dealing with black, brown, red, yellow, green, blue, and some other faded out color on the normal push button.
I have run new wire on the bottom side after removing the rotten shielded wire harness that zenith used then.
The push button wiring is not at all clear to me seeing as my schematic reading skills are lacking.
Would be great if someone had the time to look at the schematic and tell me where the leads go from the bottom side to the appropriate tone push button.
I know its asking a lot, but I could really use some expert advice on this one.
I am planning on wrapping a single wire around the harness and attaching it to chassis ground to maybe help with interference.
I made a sketch of the control panel with the push buttons labeled.
Most of my other Zenith consoles did not shield the whole harness like they did on this one. Much easier to replace crumbling wires on the others.
Everyone have a great 4th of July.
murf

[morzh]

Murf


Are the wires still connected? If yes., simply replace one-by-one.

[murf]

Yes the wires are still connected and replaced under the chassis.
But due to the colored rubber being gone on the top side, along with everything being buried in the shield I am not certain what goes where on the tone control.
What a dumb design!
I did map out the bottom side and rewired it according to what I am guessing are the correct colors. Question is where the 2 connection are on the control side.
Have been trying to figure it out by checking continuity, but that's not working out either.
Frustrated, murf

[RodB]

Hi Murf,
I took a look at the schematic and it doesn't show wire colors but there may be a clue in the list of colors you gave. They are the resistor color code and it may somehow match the list of tone switches in the schematic. This tone circuit is a feedback control that switches a network of capacitors in or out of the network. So that's the reason for the shielded wiring. I will check another source for more info.

[NostalgiaRadioTime]

I use one of these a lot when tracing out wires and components on a radio chassis. In fact it's this exact same model:

https://www.amazon.com/Sperry-Instrument...L7GJG&th=1

[murf]

That would be great!
Thanks.
murf