Oh great effects gurus, I call upon your help...

[Bulltrout]

I bought a 3pdt switch to make my crybaby :wah true bypass, and I wired it according to this diagram Linky but I do not get a clean signal. I've tried all the trouble shooting I'm capable of, but I'm a , anyone know what might be wrong?

[curtisstetka]

Well, I'm not a guru but first thing is that diagram is for a DPDT switch, not a 3PDT switch. You could certainly use a 3PDT switch but you'll have an empty pole. Could this possibly have thrown you off?


When I did this very same surgery to my Crybaby, I removed the input buffer entirely. I don't know if this is your problem but it can't hurt. If you're using true bypass, there's no need to retain input buffer components.

Perhaps you broke a trace on the board or something like that? Maybe you made a cold solder joint when you connected your new switch? Maybe your new switch is wonky.

Pictures would help if you can take a few.

[Strat Cat]

I'm thinking maybe you wired the poles wrong. From the bottom of the switch the solder tabs should look like this...

_ _ _
_ _ _
_ _ _

The 3 poles are the 3 dashes across the center. The tabs above and below are the throws for each pole. Did you possibly wire the poles and throws horizontally?

Since you're using a 3PDT switch you can use the 3rd pole for an LED

[Bulltrout]

Here is a photo - sorry should have taken the time to do that right away. Here is a link:[img=http://images5.pictiger.com/thumbs/e1/8a1cbc45f39d16fd54d7fa73896041e1.th.jpg]

[Strat Cat]

Can you post a larger photo thats a little closer to the actual switch and pot? It's hard for me to tell which wire is going where.

Since you kept the input buffer circuitry did you cut the trace near the input jack? This is a "must do" if you keep the buffer.


I would recommend removing the buffer also since it isn't needed. Did you also install "pull down" resistors to prevent pops when you turn the pedal OFF and ON? This is another "must do" when converting to true bypass.

1 _ 4 _ 7_
2 _ 5_ 8_
3 _ 6_ 9_

Lets say the diagram above is the 3PDT switch and that lugs 1,2 & 3 are being used for an LED

Here's how the rest of the switch should be wired...

Lug 6 gets connected to ground. Either by it's own dedicated wire to the chassis or to the black wire from the pot.

Lug 5 goes to the wire you solder to the circuit board.

Lug 4 gets shorted to lug 9.

Lug 9 connects to the green wire in the wiring harness.

Lug 8 connects to the purple wire from the harness.

Lug 7 goes to the blue wire from the pot.

[Bulltrout]

I cut the trace, but I have not installed the pull-down resistors - in fact I just learnt about that from you, and I will look into it. This is a terrible picture but the best close up I can do: http://images5.pictiger.com/thumbs/d...6d94cd2.th.jpg

[Bulltrout]

According to your instruction, and the diagram I have wired it properly - unless I oriented the swicth incorrectly. Here is the nooby question of the day; when I look at the switch from the bottom, should the opening on the lugs be facing me, or be horizontal to me?

[Strat Cat]

As far as I can tell by the photo you have the switch oriented correctly. It looks like my diagram only rotated 90 degrees clock-wise with lugs 7,8 & 9 on the bottom row closest to the pot. You might want to re-flow your solder joints. I've had what looked like a good solder joint end up being bad before. Re-flowing it was all it took for the pedal to start working correctly.

Did you check the cut trace with a meter for continuity? It's possible you didn't cut all the way thru the trace.

[Strat Cat]

Here's a diagarm of where the pull down resistors go. This diagram is for a board that has had the input buffer removed. I've never installed them on a pedal that kept the buffer before. The 1M resistor on the left gets connected to the bottom of the 68K input resistor and the bottom of the 350 ohm resistor. It is NOT connected to the small cap off to the side of the 350 ohm resistor. The 1M resistor on the right at the top gets soldered into a pre-existing hole in the circuit board. It is connected to the .22uf cap just below it in the diagram.

[Bulltrout]

Ok, I re-flowed all the solder joins, (they're all nice and shiny) and I ensured the cut is complete - and when I plugged it in got nothing. I think my next step is to replace the switch.

[curtisstetka]

I would suggest that before you replace the switch entirely, connect up the appropriate wires as if the switch was on. In other words, remove the switch and hardwire your wah on. Then you can determine if the switch is indeed the problem or it lies elsewhere.

I never knew of these pull down resistors??? Neat. Althouh, I didn't bother with them and my wah doesn't pop at all when switching. I must be charmed.

[Strat Cat]

I agree. I seriously doubt that the switch is the problem here. My guess is that it's bad wiring or maybe you cut the wrong trace or something like that. Does the pedal pass a signal in bypass mode?