Bringing 78-1100 back into service

Started by elwoodblue, August 18, 2026, 02:36:52 PM

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elwoodblue

I'm a bit ashamed it has took me this long to tackle this project. I'm excited that it is close to being
a fully functioning series l instrument again. It was about ten years ago that Mica and crew supplied me with
all the parts I needed to reassemble the electronics and now I just need to make all the connections.

 I've completed the stereo jack/DIN plug/battery connections thanks to Mica's PDF instructions and are about to
start the ribbon cable connections. From pictures on the interweb I can see where most the wires connect,
assuming the color coding on the ribbon cable hasn't changed over the years.
 Before I start I thought I'd better ask for guidance so I can be sure of my progress as I move forward.

I have Ron's schematics which I can pretty much follow, but I'll admit I'm a human and we know that often entails mistakes...so I'll go slow and careful with this project to make sure everything is right before I power her up.

 If there is a wiring diagram that exists that will guide me that'd be great.
Otherwise I'll ask questions about specific connections that I am unsure of as they arise until everything is buttoned up.

I know from the Jack/DIN plug/Battery PDF that;
... the Red ribbon (adjacent to arrow) goes to pin 2 on the stereo jack
...the Orange ribbon goes to pin 6 on the stereo jack
...the Yellow ribbon goes to the common ground on the side of the stereo jack

That's where I'm at now. 

I have mapped out where I think most the others go, but I thought I'd better ask for guidance in case my deduction from the pictures I've found aren't correct.

Thanks in advance for any help.
For a while I had some activators in the guitar, but I'm really looking forward to hearing 78-1100 as it was designed
to sound.

All my best, 
Kris

edwardofhuncote


rv_bass

Sounds like a great project! 😊

elwoodblue

Thanks guys,
I'll add some pics as I get going.

"It's 106 miles to Chicago, we got a full tank of gas, half a pack of cigarettes, it's dark... and we're wearing sunglasses."
-EB  8)

dela217

I have a bunch of Series instruments.    If you need a particular photo of wiring, just hit me up.

elwoodblue


elwoodblue

Here's the current sate of progress:
aug 19 progress.jpg

Michael,
 Most the pictures I've found are taken from above. If you could take a couple shots from a 45 degree angle showing the connections to the potentiometers and the connections from the pots to the mini switches...that would be immensely helpful. Many thanks  :)

mica

#7
These are snapshots from the samples. Might get you started! Ask for any clarification needed. These are funny - once Clarostat marked the pots wrong. Always makes me laugh when I see it!

elwoodblue

Thank you Mica.
 Those photos will definitely help.
They also show the jumper on pins 2 and 3 of the upper stacked pot that other photos didn't show clearly.

I'll post any more questions that arise after my next session with the soldering iron.
my best

elwoodblue

I think I'm seeing there is a jumper between pins 2 and 3 on the lower stacked pot as well.
Is that correct?

thanks

elwoodblue

I'm making a list of connections I need to make with the ribbon cable.
For this instance, I'm assigning pin numbers to the switches and pots that might be different from the standard nomenclature. I'm happy to be corrected.
 For now, this is the scheme I'm using:
For the pots; I'm assigning the wiper as Pin 2
                    The tab counterclockwise from Pin 2 as Pin 1
                    The tab clockwise from Pin 2 as Pin 3

                    I'll refer to the (Volume)pots in the stacked assembly as upper and lower "Dual" pot
                    I'll refer to the (Tone) single pot as the "single" pot
                    The stacked pot assembly, single pot and adjacent switch for each pickup will be designated as either
                     "Neck" or "Bridge"

For the Switches; If being viewed from the bottom of the instrument (right handed instrument face down, neck extending to the left)... bottom left tab will be "Pin 1"
                                   middle left tab will be "Pin 2"
                                   top left will be "Pin 3"
                                   top right will be "Pin 4"
                                   middle right will be "Pin 5"
                                   bottom left will be "Pin 6"

I think that will avoid any confusion as I find the points to connect wires and leads to.

 For the ribbon cable, these are the connections I have figured out I need to make:
I'm starting with the Brown (adjacent to the arrow on the plug) as wire 1.
 1 Brown      -neck upper dual pot pin 1
 2 Red          -neck switch pin 1
 3 Orange     -neck switch pin 6
 4 Yellow       -neck switch pin 5
 5 Green       -neck single pot pin 3
 6 Blue         -bridge upper dual pot pin 1
 7 Purple      -bridge switch pin 1
 8 Grey        -bridge switch pin 6
 9 White       -bridge switch pin 5
10 Black       -bridge single pot pin 3
11 Brown      ??
12 Red         -stereo jack pin 2
13 Orange    -stereo jack pin 6
14 Yellow      -common ground connection on side of stereo jack

 I can't see clearly where the "11 Brown" wire of the ribbon cable connects to.

After I have the ribbon cable mapped out I'll continue with the resistors,capacitors,jumpers, and the connections from the rotary switch.

Phew!   ;) This is a good excercise in being precise and succinct.












 
 
                               






Nova Constellatio


elwoodblue

Ha! ...Thanks for helping to make me smile.
I'm going through some turbulance in life now and I'm grateful for positivity that comes my way.
...and this project helps to distract me from the whirlwind of thoughts that might occur otherwise.
thanks again :D

Nova Constellatio

That's very relatable.

Good luck with Brown 11!

elwoodblue

I have soldered all the ribbon connections except for "Brown 11".
Yay for progress !!  ;D