LED oddity with my Tonebender MKII clone...

[zenpeace69]

Ok, so the pedal is wired up with a 3pdt switch in typical fashion.  The problem is that the LED will not light up when there I put my cord into the input.  If I take the cord out of the input the LED will turn on and off with the 3pdt switch.  

The pedal functions like it should when I am plugged into it.  It's just that the LED won't work.  

What do you think the problem could be?

[RickL]

It sounds like a miswired input jack. With no plug in the input jack there should be no power to the circuit so the LED shouldn't light. A properly wired stereo input jack will have the ground wire from the battery (+ in this case since the tonebender is positive ground I believe) connected to the ring of the jack and the circuit ground connected to the sleeve of the jack. When a mono plug is inserted the barrel of the plug shorts the ring and the sleeve completing the battery ground to the circuit ground.

What type of input jack are you using? I can picture a way that a Marshall style stereo jack could be miswired and give the results you describe but not a standard metal stereo jack.

[zenpeace69]

It sounds like a miswired input jack. With no plug in the input jack there should be no power to the circuit so the LED shouldn't light. A properly wired stereo input jack will have the ground wire from the battery (+ in this case since the tonebender is positive ground I believe) connected to the ring of the jack and the circuit ground connected to the sleeve of the jack. When a mono plug is inserted the barrel of the plug shorts the ring and the sleeve completing the battery ground to the circuit ground.

What type of input jack are you using? I can picture a way that a Marshall style stereo jack could be miswired and give the results you describe but not a standard metal stereo jack.

Thanks for clueing me in.  I wondered what was up with these circuits (tonebender, rangemaster) that had the positive going to the input.  I simply wasn't aware it had to go to the ring on the input.  

Thanks much for your help!  You learn something new every day...

[zenpeace69]

Wait... I am using a 3pdt switch.  I have the positive ground going to the 3pdt switch as the "in" of the circuit.  I then wired my 3pdt to the input jack.  Originally, I had it going to the main terminal of the input jack.  On your suggestion I moved it to the ring of the input jack, but it didn't change the way the LED behaved.  It still won't light up when there is a cable into the input.  It will light up when the cable is out.  

I know I am missing something really fundamental here, but I don't know what it is.  

I am using "typical" wiring for a 3pdt for true bypass on a circuit.  I am sure the fact that it is a positive ground circuit is the reason for my trouble, but I don't know how to fix it.

[zenpeace69]

Hold on... Are you saying that the positive ground isn't my "in" on the circuit?  If not, what is?  Maybe I am looking at it all wrong?

[RickL]

This can be very awkward without something to look at but I'll give it a try.

The black wire of the battery connector should go directly to the board(this is your -9v connection). The red wire should go to the ring on the input jack. The wire from the gound on the circuit should go to the sleeve on the input jack. The tip on the input jack goes to one of the centre lugs of the switch.

The LED wiring should get its power and ground connections from the board, not directly from the battery or the input jack.

Another way to look at it is to find a connection diagram for a regular negative ground 3pdt switch and reverse the battery connections (red

• wire goes where the black [-] wire went and black goes where red went). Also swap orientation of the LED. It sounds like you already have the diagram so this might be the easiest way to look at it.
  
  Both explanations mean the same thing. Pick the one that is easiest for you to follow. If I've confused you even more we can try again.  :lol:

[zenpeace69]

This can be very awkward without something to look at but I'll give it a try.

The black wire of the battery connector should go directly to the board(this is your -9v connection). The red wire should go to the ring on the input jack. The wire from the gound on the circuit should go to the sleeve on the input jack. The tip on the input jack goes to one of the centre lugs of the switch.

The LED wiring should get its power and ground connections from the board, not directly from the battery or the input jack.

Ok, I wired it just as you said in the first paragraph, but I have not done anything with the LED which is wired just as you would wire a pedal with 3pdt and TB (power to the DC jack and ground to the 3pdt).  So you are saying that I should ground the LED to the board and run the power line to where?  Where on the board will I tie into the positive?  I'm sorry... I understand most of what you are saying, but I am unclear about the LED.

[RickL]

The LED should get its power and ground from the board. I'll try a little ASCII here and see if it works:

(-9v) -> (-////-) -> (-|<-) -> (switch) -> (ground)

or

(-9v [on board]) to (current limiting resistor [whatever one you're using now]) to (LED [cathode towards -9v]) to (switch contacts on 3pdt) to (ground [on board]).

You can hook the -9v and ground from the LED to any place on the board that is directly connected to those voltages. Actually the ground from the LED could go to the sleeve of either input or output jack too. Also, I suppose the switch could be any place in that chain and still work (i.e. it could be between -9v and the resistor or between the resistor and the LED.

Now that you've changed the wiring is the pedal still working correctly (except for the LED)?

[zenpeace69]

The LED should get its power and ground from the board. I'll try a little ASCII here and see if it works:

(-9v) -> (-////-) -> (-|<-) -> (switch) -> (ground)

or

(-9v [on board]) to (current limiting resistor [whatever one you're using now]) to (LED [cathode towards -9v]) to (switch contacts on 3pdt) to (ground [on board]).

You can hook the -9v and ground from the LED to any place on the board that is directly connected to those voltages. Actually the ground from the LED could go to the sleeve of either input or output jack too. Also, I suppose the switch could be any place in that chain and still work (i.e. it could be between -9v and the resistor or between the resistor and the LED.

Now that you've changed the wiring is the pedal still working correctly (except for the LED)?

Ok, so I hooked the positive from the LED to a spot on the board that was yeilding 9 volts.  I then put the ground off the led to the output sleeve.  The pedal still works, but the LED does not light up still.

[zenpeace69]

Ok, I got it working.  I had to reverse the LED wiring and instead of sending the positive to the ground I sent it to the 3pdt switch.  I hooked the negative to a spot on the board that yielded 9 volts.  Between you and another forumite on the HC effect forum we got it working.  Thanks a bunch!

[RickL]

Glad you got it working. I've got lots of help from the generous folks on this site and it's nice to be able to give back occationally.