repairing 1970s DIY on-board distortion unit

[J M Fahey]

Good.

Buy a small roll (10 meters?) of stranded (not solid) 0.35mm^2 wire.
If the only one youŽll ever buy I suggest white or grey colour which are "neutral" ; while Red, Black, Blue or Green are typically associated to Positive, Negative, etc. and that might be misleading in the future.

In the old days I used to buy Electronic stuff in the shops along Edgware Road or Tottenham Court Road but all disappeared or at best sell cellphones and tablets.

Oh well.

[TheresanLinSolder]

Thanks, Juan Manuel - very helpful to know the size, I was wondering about that! I got it off the internet in the end - should arrive Saturday. Yes, I go to Tottenham Court Road often, and those shops are just cellphones all over, plus a few overpriced digital camera places. I bought a roll of film in one recently ... oh man! The price ...

[Mark Hammer]

The traditional means of applying power to onboard effects/circuits is to use a stereo jack. Insertion of the guitar cable into the jack will turn the battery power on, just as it would for stompboxes.

Having said that, I suspect a great many here have committed the same error I've committed at least a few times in their life, and that is to connect the black wire from the battery snap to the wrong solder lug on the jack. 1/4" stereo phone jacks are not quite as standardized in the location of the different solder lugs as we'd probably like them to be, so it is also possible the battery snap is soldered to the wrong lug on the jack.

[vintagekiki]

OK ...

[ATTACH=CONFIG]54696[/ATTACH][ATTACH=CONFIG]54695[/ATTACH]

The PCB is definitely factory.
Is there any information on the printed side.
Which guitar is it (model)

[TheresanLinSolder]

vintagekiki - on the reverse the PCB has a large metal area in the middle, with SF-1. That number may continue - there's a wooden post into which the board is screwed, which obscures any other letters (the post, I think, used to be glued to the guitar body, to keep the thing in place - it's now unstuck). The guitar is an old LP copy, branded Saxon, which I believe was marketed by Selmer, and sold under other badges in other countries. I have a fantasy that the guy who did this work is going to appear on here, saying, that was my first project and I'm now a famous engineer ...

Mark Hammer, and others, thank you - I've googled for images of mono vs stereo jacks - the "in" on my guitar is indeed stereo, the two "outs" are mono. There's a black, presumably earth, which appears to go from the stereo-in across to the extra mono out, then from there to the back of the Expander knob, then to an area I can't make out. The earth from the board (per 52 Bill's list above) goes first to the 1-tone-2 switch, then to the area I can't see. That area is the rear of the Balance knob and the on/off switch.

Is it reasonable to assume that in the obscured area the 1-tone-2 earth connects to the balance then the on/off, and then out to the expander and so on? In other words that we have one long chain of earths from the board, to each adjustable control, then to each of the extra sockets? If so, may I connect the battery ground to the black connection on the board? Or should I still go to the stereo socket? Or just any easy place along that chain? (The guitar's original socket is out of this loop, it has thicker wires, in red and grey.)

[vintagekiki]

If it's not too much of an effort upload a photo of a guitar body with magnets and commands, that I try to find some information about it.
Since this is an active guitar, a stereo jack is required to turn the battery off when the guitar is not in use.
In the meantime, browse through this book.

https://pdfslide.net/documents/guitar-electronics-for-musicians-donald-brosnac-568a016c5fdcc.html

In the book you will find how to connect the battery to the jack.

Question
What the guitar has from the controls and built-in effects

[vintagekiki]

SF-1 Schematics

Just to find the schematic
https://reverb.com/item/245371-100-original-60-s-shin-ei-sf-1-super-fuzz

https://images.reverb.com/image/upload/s--zEYhTTTP--/a_exif,c_limit,e_unsharp_mask:80,f_auto,fl_progressive,g _south,h_620,q_90,w_620/v1408469807/vnzrm04io6bryshutwsz.jpg

Here is the schematics

https://www.diystompboxes.com/smfforum/index.php?topic=101740.0

https://www.diystompboxes.com/pedals/ShinEi_Companion_Fuzz.gif

http://web.archive.org/web/20160306132556/http://ustomp.com/files/superfuzzschem.gif

http://www.gear-review.co.uk/reviews/duofuzz/fuzz_4.jpg

Here you can see how to connect the battery to the jack.

http://rezzonics.blogspot.com/2014/11/shin-ei-fuzz-wah-univoxunicord-super.html

If you have a potentiometer with a switch, the switch is for on / off batteries. In that case, schematics connectivity is here.

http://files.effectsdatabase.com/docs/schematics/unicord_superfuzz.gif

[TheresanLinSolder]

Thanks so much, Vintagekiki. Yes, I can see that one of the sockets on the guitar (the input) is stereo. The guitar was made as an ordinary, quite cheap, Les Paul copy. The effect was added by a previous owner. As friends on here have said, it's actually a real factory PCB, but it was not originally on the guitar. So, the guitar is just a regular LP - pickup selector, 2x vol and tone - but then it also has the Balance/Expander and 1-tone-2 of an FY-6/Superfuzz. There is also a small on-off switch with "Shin-ei" in tiny writing on top.

My parts have arrived today, so I'm going to have a go now ...

[TheresanLinSolder]

IT WORKS!!!

!!!

I can't thank you all enough.

For the record ... I removed the brown wire that I'd mistakenly attached to the battery clip. I attached it to the switch, on the next lug from the blue wire, per the list that Bill gave. I then put a new piece of black wire on the battery clip, and attached it to the stereo jack (https://www.cigarboxguitar.com/knowl...ars-amps-more/). After I'd eventually found a battery that wasn't flat (!), I inserted it, put the rear cover back on the guitar, plugged into a small practice amp, and got the clean sound first. I turned all vols/gains to 0, then pressed the on switch. As I turned up the amp vol a little, and put the neck pickup to 3, I wasn't expecting anything, but immediately there was a slight fuzz. Got it all up to a sensible volume, and kerpang! It actually produced a sound, and that sound was manipulable by the knobs and switch. It's true that it's deafening, but what does that matter?

So, my other question was, would it sound any better 40 years later, now that I can play? You bet! It's beautiful! The fuzz itself is the best one I've got, and when the octave kicks in, it's fantastic. This little old guitar has a new lease of life. I think I would tell my 14 year old self, just try not putting everything on 10. That's why it squeals.

This has been great fun, and there's no way I could've done it on my own. I'm now contemplating buying a kit and trying to build something else. Treble boosters seem not to have too many parts, so I might try one of those.

Thanks again everyone!

[vintagekiki]

I'm now contemplating buying a kit and trying to build something else. Treble boosters seem not to have too many parts, so I might try one of those.

If you want to build, listen to sound clips from Ultrasonic XII.

http://www.vintageguitarandbass.com/vox/Ultrasonic_soundclips.php

Construction is extremely simple.

https://www.acidfuzz.com/pages/vox-guitar-fx

https://music-electronics-forum.com/attachment.php?attachmentid=34132&d=1432849556

https://music-electronics-forum.com/showthread.php?t=39569&p=385933&viewfull=1#post385933

Be sure to let us know, how your first project is progressing.

[TheresanLinSolder]

Cool! Will check it out.

[vintagekiki]

If you decide to DIY flip through these addresses ... ...

http://tagboardeffects.blogspot.com/

http://www.generalguitargadgets.com/

http://freestompboxes.org/

https://www.diystompboxes.com/smfforum/

http://fuzzcentral.ssguitar.com/schematics.php

http://www.luciferstrip.com/fuzz/

http://experimentalistsanonymous.com/diy/index.php?dir=Schematics

And download books ... ...

https://www.scribd.com/document/371010089/Electronic-Projects-for-Musicians-by-Craig-Anderton

https://www.scribd.com/doc/39149560/The-Stompbox-Cookbook

https://www.scribd.com/document/93411742/DIY-Projects-for-Guitarists-Craig-Anderton