American Fuzz Pro – Help with first build diagnostic/troubleshooting?

[Anonymous]

Hi all, after some effort I managed to complete my first build – the american fuzz pro.  Unfortunately as is common with beginners upon completion it does not work as intended.  While I have sound in bypass, engaging the effect produces no sound whatsoever.  I probably should have asked for help sooner, and over the course of re-wiring it’s possible I’ve damaged the 9v in pad (although it still seems to read 9v at the solder point).  I tried wiring it both with the traditional DPDT wiring and with the DPDT PCB that came with my kit following the guides on the site – both produced the same result.  When I had it wired traditionally with the LED in D1 it did not light when the effect was engaged.  I’ve attached a few pictures with the hope that anyone might be able to offer some advice for how I would begin to diagnose the problem.  I’ve checked each solder point for continuity and they seem to be okay (albeit ugly).  Even though it hasn’t been successful I’ve learned a ton and will continue to keep at it.  Any advice or help would be greatly appreciated – thank you so much in advance!

[Billy]

We’d need to see a picture of your 3PDT wiring as it is now so we can trace the wiring

It looks like your main pcb IN and OUT ‘T’ for tip pads go to the 3PDT as they should, the black wires, but we can’t see where, it also looks like your orange ground wires go to the jack grounds

Double check your battery snap ground is in fact soldered to the ring lug on the stereo IN jack and not the tip, put a jack in and follow the connections around like below you could have your ring and tip connections mixed up

Not all jack sockets are laid out the same your tip and ring solder lugs may be different so stick a jack in and check

[Cybercow]

gabbaghoul – it appears both the “IN” & “OUT” wires on the PCB are reversed. Swap the orange & black wires at PCB “IN” and the PCB “OUT” and you should re rockin’.

[Anonymous]

Hey Billy and Cybercow! Thank you both for your replies – here’s a better look at the 3PDT switch – hopefully it’s more visible – just wanted to double check before I try anything (or mess it up furthere :S).  You guys rule – thanks so much again.

 

[Anonymous]

Just a quick follow-up – I’ve double checked the input and output jacks and they’re definitely wired to the correct lugs.  Cybercow – It’s very possible I’m overlooking something completely obvious, so apologies for my slow understanding – right now on my PCB I have IN (T) on wired to B1 on the 3PDT PCB and the other IN connected to the sleeve lug of my input jack.  OUT (T) is connected to BO on the 3PDT PCB and the other OUT is connected to the sleeve lug on my output jack.  Does this sound right?

Again, many thanks for everyone’s kind help and patience.

Best,

G.

[Billy]

G zooming in  I could see your main pcb in and outs were correct just couldn’t see where they went to on the 3PDT from what you say that’s correct in T to BI out T to BO other pads to jack grounds

Did you check your IN jack tip wire from the 3PDT goes to the in jack tip solder lug and not the ring

Also need a clearer picture of your DC jack wiring

Make sure you’re putting your in cable to the in jack again very easy to plug your cables into the wrong jacks when you’ve got it upside down etc

[Anonymous]

Hey Billy – thanks so much for your reply.  I’ve double-checked the jacks and I’m confident I have them connected to the correct lugs – I switched to the two that came with the kit just for familiarity’s sake.  Here’s a pic of the input jack:

And here’s a closer (hopefully useful) pic of the rear of the DC jack:

Thanks again so much for your help!

G.

[Billy]

All your components look to be the correct value and orientation

To double check you are getting power to the main pcb take the voltage on the top end of R3

Also continuity check your T pads from the main pcb to 3PDT pcb BI and BO pads and check continuity on your ground connections to 3PDT and jack ground lugs also check continuity from your I and O to the jack socket tips you don’t have to remove your heat shrink just touch the actual sockets tip and sleeve

Make sure your 3PDT also has continuity from the middle common row 3 lugs to their corresponding 3 top row lugs (effects mode)

If this all checks out post the voltages for Q1 to 3s emitter, base and collector legs

 

 

[Cybercow]

I brought up the potential of crossed main PCB wires only because black wire is typically used for ‘ground’. I just can’t tell where the black wires on the “T” pads of the main PCB “IN” and “OUT” go.

[Anonymous]

Hey guys thanks so much again – I can’t tell you how much I appreciate everyone’s help.  Unfortunately over the course of working and re-working this project the pad of 9v in has burnt off (a beginner’s mistake, I know) but now I just cant seem to get a wire to connect – I think it’s possible that this was the main cause of my issues to begin with.  Pending any ideas of a work-around I’ll re-order a another PCB and try again (the components should be okay). I’ve learned a whole lot and I think I can get it right if I give it another go.

Again a huge thank you to Billy and Cybercow – this is a great community and I can’t wait to show off the pedal once it’s complete.
Best wishes,

G.

[Billy]

G just wire your 9v straight to R3 top end leg the side that doesn’t have continuity with C2

Mark I had the luxury of being on my PC that day so could zoom in and see the wires my immediate thought was the same as yours black = ground but easy to zoom in 10x on your PC not so on my phone

[Anonymous]

Oh my god it works!  Hahaha!  Unbeliveable!

So it must have been the bad connection I made at 9v in – crazy.  Billy – thank you so much!  I was sure I was out of luck…  Can’t thank you enough.  I’ll be sure to post it to the completed projects forum once it’s all boxed up. 🙂

Again, many thanks to everyone!

Best,

G.

[Anonymous]

Before I take on the challenge of drilling my first enclosure – If I may ask one more question?  I’ve wired a standard LED to D1 (anode in centre position and cathode in the non-white pad.  I’ve also added the R13 3k3 resistor to the CLR space on the 3DPT pcb, but it still doesn’t light when the effect is engaged… Not the end of the world, but Is this the correct configuration?  Thanks so much, again!

Best,
G.

 

 

[Billy]

Great glad you got it going

The LED must be on the 3PDT pcb so I’m assuming you mean D1 on the 3PDT pcb and not the main pcb

It’s correct your LED anode long leg + goes to the middle and cathode – to non white boxed pad

You can check your LED is ok by using a coin cell battery if you’ve got one just stick it in the middle of the 2 legs

If your CLR and LED are mounted on the 3PDT pcb you can use your meter to check it gets power and ground, check from the 9v pad to the CLR and from the other end of the CLR to the LED anode for voltage and or continuity

If you DC jack power and ground go directly to the 3PDT pcb your faulty 9v pad shouldn’t make a difference

 

 

 

[Anonymous]

Thanks Billy – this is how I have it now. I checked the LED with my DMM and it lights on its own.  When you say check do you mean for continuity?  So sorry for my lack of understanding – I’m still learning the very basics. Thanks so much, again – worst case scenario I can always just proceed without the LED.

[Anonymous]

There doesn’t seem to be continuity between CLR and the other points, so perhaps the 3k3 resistor was damaged when I removed it from R13.  I’ll try to find another one to try in its place.  Thanks so much again!

Best,

G.

[Billy]

It could just be a cold solder joint the resistor should be fine just reflow the CLR solder joints apply your iron for about 5 seconds until you see the solder flow on the topside would be easier

FYI   you’d get continuity from the 9v pad to the CLR then the other side of the CLR should have continuity to the LED anode, then ground should have continuity to the LED cathode when it’s in effects mode

If you set your meter to 20V DC the V setting with the dotted and straight line (see below) put your black (COM) probe on any ground point and touch your red probe to the LED anode to see if you get a reading you can do the same for the 9v pad and the CLR

This shows where you should get continuity red 9v and yellow ground in effects mode, just ignore the blue line the best way for you to continuity check is to for example put one probe on the 9v pad and the other on the actual CLR leg rather than the solder joint then from the other side of the CLR leg to the LED anode leg that way you’re checking your wire to the LED is also ok then with it in effects mode touch the actual LED cathode leg and any ground pad or the 3PDT lug with the yellow line

Have a look at the beginners guide to components where it explains how a 3PDT works

[Author]

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