Rpschultz13
Active member
Odd issue. Sounds great when engaged, but in bypass mode I get no sound. I *think* this is True Bypass. What would cause no sound when bypassed?
King Nothing, TB no sound?
- Thread starter Rpschultz13
- Start date
Tassieviking
Active member
The only thing I can think of is a bad contact in the stomp switch, because it works when the effect is on proves there is a signal going into and leaving the stomp switch.
On bypass the contact should be closed on the top left terminal to the middle left terminal on the switch. (looking at the back of the pedal with the cover off)
The signal from the input goes to pin 1 of the terminal strip of the switch PCB, and then to pin1 on the switch itself.
The output signal goes through pin 6 of the switch PCB, and then to terminal 2 of the switch itself so there is nowhere to loose the signal except in the stomp switch itself.
On bypass the contact should be closed on the top left terminal to the middle left terminal on the switch. (looking at the back of the pedal with the cover off)
The signal from the input goes to pin 1 of the terminal strip of the switch PCB, and then to pin1 on the switch itself.
The output signal goes through pin 6 of the switch PCB, and then to terminal 2 of the switch itself so there is nowhere to loose the signal except in the stomp switch itself.
Rpschultz13
Active member
I wondered about that. So I jumpered the top left/right pins on the switch thinking I'd create the standard bypass wiring. That didn't help. So now I'm more confused than I was.
Rpschultz13
Active member
So I should remove the switch and wire in a new 3PDT the old fashion way... probably. I'm not sure if the main PCB is marked.
Tassieviking
Active member
This is the signal path to the switch.
Try placing a jumper between 1 and 2 on the switch when you have it in bypass mode.
The signal has to come to terminal 1 and 6 of the Switch PCB or it would not work in normal mode.
Try placing a jumper between 1 and 2 on the switch when you have it in bypass mode.
The signal has to come to terminal 1 and 6 of the Switch PCB or it would not work in normal mode.
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Tassieviking
Active member
I think the problem is in the switch itself, but I have been wrong in the past.
I would replace the switch but if I was you I would check it with a meter first before doing anything.
I would replace the switch but if I was you I would check it with a meter first before doing anything.
Rpschultz13
Active member
I agree it seems like it's the switch.
I checked the switch with a MM, seems fine in both play and bypass.
Next most likely is that 3DPT board, or some of the connects between them. I used a 6 pin header.
I suppose next step is to take the switch and 3DPT board out and hand wire a new one in. Thanks @Tassieviking for the wiring diagrams.
CtCE is closed until late July so I can't get a new 3DPT board until then, if it is that.
I checked the switch with a MM, seems fine in both play and bypass.
Next most likely is that 3DPT board, or some of the connects between them. I used a 6 pin header.
I suppose next step is to take the switch and 3DPT board out and hand wire a new one in. Thanks @Tassieviking for the wiring diagrams.
CtCE is closed until late July so I can't get a new 3DPT board until then, if it is that.
MichaelW
Well-known member
Try putting it in Bypass mode, then partially activate the switch, like push down the slack until you feel resistance and jiggle it a few times without activating it.
I've had this issue with one particular brand of 3PDT. The red 1kg stomps from Tayda. I've had pedals I've built years ago now start doing this.
My suspicion is that I used too much heat when soldering the daughterboard. They are not as heat resistant as some of the other brands like the ones from SBP.
Rpschultz13
Active member
Well I removed the old switch/pcb and wired a new switch in - the old fashion way. It works.
I know those pcb switch boards are SO nice, doing it the old way took a long time. But I will say the amount of heat you have to put in is a lot less for a single wire than filling a PCB hole. FWIW.
I know those pcb switch boards are SO nice, doing it the old way took a long time. But I will say the amount of heat you have to put in is a lot less for a single wire than filling a PCB hole. FWIW.
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Tassieviking
Active member
That small PCB is an adapter PCB so you can mount SMD components onto TH PCB's.
It looks like there is a MMBFJ201 SMD transistor mounted on it, it also looks like the legs are standard SIP pins.
Some people sell the PCB bare and others will sell them with a MMBFJ201 already mounted.
Tayda has some PCB's.
www.taydaelectronics.com
DIY guitar pedals AU:
Pedal PCB have them mounted:
You have to look around if you want some, I have made up some footprints for KiCad that lets you do TH and SMD on the transistors.
The easiest way to put them on a PCB is just place 2 footprints for the component, one TH and one SMD and then rout them both in place in parallel.
It looks like there is a MMBFJ201 SMD transistor mounted on it, it also looks like the legs are standard SIP pins.
Some people sell the PCB bare and others will sell them with a MMBFJ201 already mounted.
Tayda has some PCB's.
SMD Transistor to TO-92 PCB
DH Electro Acoustics - Get It Fast - Same Day Shipping
www.taydaelectronics.com
Jfet Adapter Board (Sot23) - AUD $0.10 : diyguitarpedals.com.au, A shop for all diy guitar pedal enthusiasts!
diyguitarpedals.com.au Jfet Adapter Board (Sot23) - Dimensions:4mm x 4mm (approximately) Imporant Note: Jfet Adapter Board (Sot23) A SOT-23 adapter board for converting SMT Jfet's (mmbfj201 & mmbf5457 for example) to throughhole. Be sure to check the pinout of the SMT jfet to ensure a match...
www.diyguitarpedals.com.au
You have to look around if you want some, I have made up some footprints for KiCad that lets you do TH and SMD on the transistors.
The easiest way to put them on a PCB is just place 2 footprints for the component, one TH and one SMD and then rout them both in place in parallel.
Tassieviking
Active member
My limit on SMD is 1206 size, and normal SOIC-8 size for Op Amps.
I did one PCB as a front panel for an amp and I placed tiny SMD LED's under the knobs so they would glow, that looked fairly nice but a bit fiddly to make. (SMD pinheader on the inside for connections)
I think these days it would be fairly simple to leave a TH and a SMD footprint on a PCB for the same FET or transistor, it takes up a very small amount of room and it gives you a choice of what component to use.
I did one PCB as a front panel for an amp and I placed tiny SMD LED's under the knobs so they would glow, that looked fairly nice but a bit fiddly to make. (SMD pinheader on the inside for connections)
I think these days it would be fairly simple to leave a TH and a SMD footprint on a PCB for the same FET or transistor, it takes up a very small amount of room and it gives you a choice of what component to use.