Restoring/modifying original Jordan Boss Tone. Please help!

[Beard]

Hello,

This is my first post here. First of all I know next to nothing when it comes to electronics, circuit boards, soldering or anything of the sort although I have been a musician all my life. Hopefully you guys will be able to point me in the right direction.

My father gave me his old Boss Tone when I was a kid and ive always had it sitting around. It worked but it would have to be held at just the right position otherwise you would just hear the radio through it or just get nothing. This thing is pretty beat up and the knob for the volume pot is missing. I recently decided to take it apart and make it a foot pedal and change a few things on it like put in new potentiometers and install a foot switch and change the input jack so it could be used on the floor instead of attached to the guitar.

I ordered a bunch of parts and got started today. I desoldered the old pots and installed new ones. I bought 100k pots because thats what was printed on the old ones. The only thing I did different is now there is about a 2" length of wire connecting the pot to the circuit board. I soldered all the connections and plugged it in to try it. Here is where I ran into problems:

When the Boss Tone is on the off position I get no sound. When I turn it on I get a radio station and nothing from the guitar. If I wiggle the on off switch around I get different stations. The pots seem to work because when I turn the attack and volume up it has an effect on the radio coming through. I built a pretty rad radio!

Like I said before this stuff is completely new to me and I try to do research and read about this stuff but im kind of stuck at this point. Any suggestions? Am I missing something simple?

[LucifersTrip]

A repair is really something you should undertake after you have a couple builds under your belt, since troubleshooting (for beginners) can be the toughest part.

first, you get the schematic:


then, you find the proper voltages (transistor lugs in this case) with a google search or from other Bosstone troubleshooting threads here, and compare to what you have. that will help pinpoint the problem. you'd probably post those voltages here and others may help

this is also a common tool:
http://www.diyguitarist.com/PDF_Files/DIY-AudioTester.pdf

In your case, when the circuit was in the original enclosure, it sounded like a bad connection. it's common to pick up a radio station (especially in a plastic enclosure), but you should also get the effect at the same time...

honestly, I would buy a breadboard and some parts and actually build the Bosstone...then try to repair the original

good luck


ps:
 

[PRR]

[Beard]

Thanks a lot for the info. I guess I just have a ton of learning to do. I thought this project would be as simple as unsoldering and then soldering in the new parts since they are the same. I know I could buy or build a new copy. I more so just wanted to get this this fixed up instead of just having it lay around which it will probably do now anyway.

I will definitely use your info as a starting point. Thanks.

[R.G.]

The original Boss Tone is *very* prone to RF oscillation if everything isn't right. I've found that wire position and parts values were critical in the several clones of this that I've done. The symptoms you give - audio in bypass and radio stations when engaged - imply internal RF oscillation a lot. RF oscillation can be so strong that no audio can get through.

[zombiwoof]

Mahoney Guitar Gear makes clones of Bosstones and other pedals from the same company, floor box versions of the pedals, and an adapter that allows you to use the plug-into-guitar Bosstone as a pedal.  They also sell parts for Bosstones, like the knobs, switches, and other parts.  Here's their address:

http://www.mahoneyguitargear.com/

This seems to be a new website, so they don't list the parts yet, I would call or email them if you want to buy any knobs or other parts.  I bought two knobs for my old Bosstone, they make exact copies of the original parts.

Al

[LucifersTrip]

Thanks a lot for the info. I guess I just have a ton of learning to do. I thought this project would be as simple as unsoldering and then soldering in the new parts since they are the same. I know I could buy or build a new copy. I more so just wanted to get this this fixed up instead of just having it lay around which it will probably do now anyway.

I will definitely use your info as a starting point. Thanks.

we'll definitely try to help if you go for it now...if it doesn't work, first step after new-boxing would be to report the voltages

good luck

[brett]

Hi
The Bosstone circuit is a bit like the Fuzzface in that the +ve power supply rail is AC-grounded via the battery. The internal resistance of a battery can be quite high. To make the +ve supply rain more like a "proper" ac gorund, I suggest connecting a largish capacitor between the + and ground (100uF should do the trick).
Also, in messing with this circuit, I've found that using a modern NPN transistor can ruin the sound (too much gain). It also increases the chances of oscillations. If you replace one or both of the transistors, or build a whole new circuit, please send the transistors or board to one of us for measurement.  My instinct is that the "right" hFE/gain for the NPN transistor is about 150, maybe up to 180. It would be great to check the properties of an original device.
cheers

[PRR]

Gain depends directly on hFE of Q2 (the PNP), hardly at all on Q1.