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Fender Blender bypass switch kills signal when off.

Posted: Wed Aug 27, 2014 3:52 am
by K2000
Fender Blender (reissue). When I bypass the effect, it won't pass a signal. Pics below... anybody know what the likely issue would be?

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(Tone Boost side, but since I'm posting pics anyway...)
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Re: Fender Blender bypass switch kills signal when off.

Posted: Wed Aug 27, 2014 3:58 am
by K2000
Schematic here, if that helps...

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Re: Fender Blender bypass switch kills signal when off.

Posted: Wed Aug 27, 2014 5:26 am
by Moose
If it passes signal as it should do when "on", then this means the circuit itself, plus the jacks and wires and power all works fine.


To me, it'd make sense that the switch itself is broken, or at least there's something wrong with the bypass wiring?



This is assuming it's true bypass, unless I'm being blind and I'm not seeing buffered bypass there?

Re: Fender Blender bypass switch kills signal when off.

Posted: Thu Aug 28, 2014 8:48 pm
by K2000
A problem with the bypass wiring makes sense to me, but I don't know which lug that would be. :idk:

All the soldering appears okay to me, although I don't really know for sure.

What should I do?

Re: Fender Blender bypass switch kills signal when off.

Posted: Fri Aug 29, 2014 10:58 am
by KaosCill8r
Maybe first just heat up the switch connections to rep low the solder. Might just be a dodgy joint. If that doesn't work then solder in a new switch.

Re: Fender Blender bypass switch kills signal when off.

Posted: Fri Aug 29, 2014 12:12 pm
by Mike
Yeah, if it was working before, it seems like the switch to me. Those x-wing switches are not very good.

I'll have to assume that the switch is setup for true bypass, since it doesn't match the schematic.

If that is the case, grab a paperclip. Use it to temporarily connect the two switch lugs that are connected to the (0-Ohm jumper) resistor on the switch. Does it put out bypassed signal? Replace the switch.

If it doesn't work, put the paperclip between the two middle lugs. Does it put out bypassed signal? Replace the switch.

Otherwise, more troubleshooting would be needed.

Mike

Re: Fender Blender bypass switch kills signal when off.

Posted: Fri Aug 29, 2014 11:01 pm
by eatyourguitar
I have repaired numerous guitar pedals that came into my shop with this exact problem. everything that is true bypass will pass a signal with or without power even if the switch is broken. the fact that it passes a signal does not indicate any particular problem. the fact that it does not pass a signal after you toggle the footswitch just tells you that some where between the input jack tip footswitch lug and the output jack tip footswitch lug something is either grounded or disconnected or the pcb needs a repair. with the power disconnected, check the footswitch by using a multimeter set to OHMS (resistance). if you have a meter that beeps, it will help, if not, just check for resistance < 50 OHMS. check each lug to each other lug one by one. write down what connects to what. < 50 or a beep means it is connected. then toggle the footswitch. do the test again and write down the results. you will need to use your knowledge of switches and common sense to determine if the switch is bad.

if the switch is good, check power at the pads on the board where it comes in. do this with the power on.

if the board has power and the footswitch is good, your pedal needs a professional repair. if you still want to work on it check my old video on probing for problems.

[youtube]http://www.youtube.com/watch?v=sKP8Y64IK90[/youtube]
KaosCill8r wrote:Maybe first just heat up the switch connections to rep low the solder. Might just be a dodgy joint. If that doesn't work then solder in a new switch.
I would advise against this. footswitches can fail pretty fast when you are heating them up. especially if the person doing it does not have both proper equipment and experience. I only reflow a non-functioning switch if it has visible signs of dry solder, cracked solder, oxidized waxy or green solder etc.. or if I'm just connecting a broken wire. %100 of the time when I find a bad footswitch that is not a super rare russian muff, I will swap it for new.

Re: Fender Blender bypass switch kills signal when off.

Posted: Sat Aug 30, 2014 2:49 am
by KaosCill8r
eatyourguitar wrote:I have repaired numerous guitar pedals that came into my shop with this exact problem. everything that is true bypass will pass a signal with or without power even if the switch is broken. the fact that it passes a signal does not indicate any particular problem. the fact that it does not pass a signal after you toggle the footswitch just tells you that some where between the input jack tip footswitch lug and the output jack tip footswitch lug something is either grounded or disconnected or the pcb needs a repair. with the power disconnected, check the footswitch by using a multimeter set to OHMS (resistance). if you have a meter that beeps, it will help, if not, just check for resistance < 50 OHMS. check each lug to each other lug one by one. write down what connects to what. < 50 or a beep means it is connected. then toggle the footswitch. do the test again and write down the results. you will need to use your knowledge of switches and common sense to determine if the switch is bad.

if the switch is good, check power at the pads on the board where it comes in. do this with the power on.

if the board has power and the footswitch is good, your pedal needs a professional repair. if you still want to work on it check my old video on probing for problems.

[youtube]http://www.youtube.com/watch?v=sKP8Y64IK90[/youtube]
KaosCill8r wrote:Maybe first just heat up the switch connections to rep low the solder. Might just be a dodgy joint. If that doesn't work then solder in a new switch.
I would advise against this. footswitches can fail pretty fast when you are heating them up. especially if the person doing it does not have both proper equipment and experience. I only reflow a non-functioning switch if it has visible signs of dry solder, cracked solder, oxidized waxy or green solder etc.. or if I'm just connecting a broken wire. %100 of the time when I find a bad footswitch that is not a super rare russian muff, I will swap it for new.
I partly agree.

I have done it. Mind you I did use a heat sink clamp on each lug I heated. Also blew hard on the lug after also. I have never had a problem doing this. I did however think looking at the switch there would really be little to loose. It wouldn't be too expensive or difficult to replace if it all went wrong.

Re: Fender Blender bypass switch kills signal when off.

Posted: Mon Sep 01, 2014 7:16 pm
by greeny23
can you like, draw up the wiring you used? maybe check continuity of the jumper resistor.