Foot Switch troubles.....

[C Moore]

Got a FS from Mojo that has a Red LED as well as the switch. When I use it to turn the Trem On and Off, it does not work. When I insert the FS it turns the Trem On, regardless of what position the switch is in. The problem seems to be the LED and 1k resistor. When I disconnect one side of the LED, the switch functions normally. But then, of course, there is no indicator light to show if the switch is On or Off. Is there a problem with the value of the resistor.?
Thank You
This shows the trem circuit.......
http://www.webphix.com/schematic%20heav ... 12_6v6.pdf

[buildafriend]

"From my experience," 1k resistors are protocol to go into your A-typical light emitting diodes ( at least in all the pedals I have made). What you need to figure out is how the inside of your switch works. is it single pole single throw (SPST)? double pole double throw (DPDT)? or triple pole double throw? there are lots of possibilities. how is it wired on the inside? It's possible your sleeve on your cable is shorting out the switch on a balanced input jack... I cant answer much without knowing what connections are inside the pedal.

look up how the FS works and how the effect gets put into the circuit on your amp.

i hope that is helpful.

[C Moore]

"From my experience," 1k resistors are protocol to go into your A-typical light emitting diodes ( at least in all the pedals I have made). What you need to figure out is how the inside of your switch works. is it single pole single throw (SPST)? double pole double throw (DPDT)? or triple pole double throw? there are lots of possibilities. how is it wired on the inside? It's possible your sleeve on your cable is shorting out the switch on a balanced input jack... I cant answer much without knowing what connections are inside the pedal.

look up how the FS works and how the effect gets put into the circuit on your amp.

i hope that is helpful.

Do the best I can with your questions.......
I assume the switch is SPDT. There are 3 lugs, and the switch uses 2 of them.
Not sure how the "sleeve on the cable" can be shorting. The switch turns On and Off according to the continuity function of my meter. Like I said, with one leg of the LED lifted, the Trem does not turn On all by itself; the switch functions "normally".
The LED and resistor are wired in series with each other. The resistor is wired to the Tip of the plug, and the LED is wired to the sleeve of the plug. Of course, the other end of resistor and LED are wired to each other.
If I lift one end of the LED, the switch and Trem work as they should. Thanks

[martin manning]

The trem is activated by the footswitch grounding the cathode resistor of the driver stage. The diode resistor combination is wired across the switch so that the diode is forward biased and conducting, in effect shorting the switch.

If you want an LED indicator, you could use a DPST or DPDT switch and provide a battery for the LED in the footswitch box.

Another option is to put the LED in series with the switch and lose the 1k resistor, which makes the diode drop part of the driver's bias voltage. You might need to adjust the value of the cathode resistor in the amp, and you might also get a trem-frequency pulsating LED (which might be cool).

[C Moore]

Hey Martin -
That is kind of what I figured. Thanks for putting it in easy to understand terms.
The foot switch works normally without the LED, so I will let the next owner worry about this problem I think........
Thank You