Boss DS-1; The light is on but nobodys home

[thendrix]

I have an issue with a Boss DS-1. When I turn the pedal on, the light comes on but there is no change in sound. I have the distortion and level pots set at about half way and the tone pot a little past half way. Please keep your answers simple as I am new to the whole electronics game. Thanks.

Tyler

[Mark Hammer]

Switching on all Boss pedals is electronic. They generally use field-effect transistors (FETs) to do this. When an appropriate voltage is applied to one of the pins of the FET, the other two pins behave as if it is a very low resistance piece of wire. Not as low as actual wire, mind you, but low enough. When the voltage is removed, those same two pins now have a very high resistance between them, similar to, though obviously not as high as, a broken wire.

The FETs in the pedal are "actuated" by what is called a "flip-flop" circuit. This is a circuit that has two outputs, each of which can either go nowhere (as is the case in flangers, chorus, and delay pedals) or to a specific FET. When one of those outputs is "high" (applying a voltage), the other is "low" (no voltage). A momentary switch flips it from one being high and the other low, to the reverse state. Each momentary switch action causes it to flip and flop, such that when one or some FETs are in a low-resistance state, the other/s are in a high resistance state.

Now, the LED is turned on by the same voltage and flip-flop output that turns on the appropriate FET. So, it would seem that there is nothing wrong with the flip-flop circuit itself. Rather, the problem would seem to stem from the flip-flop not making the FETs change state. That could be because of something wrong with the FETs, or something amiss in between the flip-flop and the FETs.

[oc disorder]

To further illuminate what Mark said here's a schematic I scribbled on.
Have you got a multimeter ?
If you have R33 should measure 1 megohm as should R32.
Check D7 that feeds Q6 and Q7.
Although not exactly the same as the boss circuit this "interactive" circuit
shows how a flip flop changes.
Bistable Multivibrator (Flip-Flop)

Thats probably enough for starters...

[Mark Hammer]

Now THAT's teamwork! Thanks.

[thendrix]

Wow thanks for the help guys. I will check it out