[Billy]

Ignore what I said regarding collector voltages

The correct voltages as you said at the start are in the V3 build doc

Q1 Emitter: 0V, Base 0,58V, Collector 1,2V
Q2 Emitter: 0,88V, Base 1,2V, Collector 2,3V

So back to the base of Q1 not getting anything there’s not a lot of components prior to it and if you get signal up to the base that indicates they are ok looking on my PC the solder joints at Q1 do look dry I don’t know whether you took the image after changing to a socket if the transistor was tested ok on your breadboard we can rule that out so I’d reflow those joints again

Q1 base needs current to operate and that would have a knock on effect check that non of the socket holes have continuity sometimes solder can pool underneath the socket where you can’t see it and cause a bridge

[Billy]

edited*

Are you definitely taking your readings with your meter set to DC voltage

R3 and 4 as far as I can see look correct R3 looks like a 47K so not far off 51K but I can’t make out if the last band is red or orange obviously it should be orange for 47K, R4 is 22K from what I can see

Double check your ground connections sometimes with strange voltages it’s simply a poor ground connection especially with your reading on Q1 emitter which is connected to ground or you’ve simply mixed up your Transistor CBE with your initial readings which is easy to do

 

[Billy]

With regard to effects pedals it’s not critically important

Tonmann did a post on the old forum explaining how to work out if your input was in or out of phase with your output

https://guitarpcb.webs.com/apps/forums/topics/show/13151076-tonmann-phase-determination-guide

This is a good explanation taken from this site

What is Phase?

Audio waveforms are cyclical; that is, they proceed through regular cycles or repetitions. Phase is defined as how far along its cycle a given waveform is.

The measurement of phase is given in degrees, with 360 degrees being one complete cycle.

One concern with phase becomes apparent when mixing together two waveforms. If these waveform are “out of phase”, or delayed with respect to one another, there will be some cancellation in the resulting audio.

This often produces what is described as a “hollow” sound.

How much cancellation, and which frequencies it occurs at depends on the waveforms involved, and how far out of phase they are (two identical waveforms, 180 degrees out of phase, will cancel completely).

[Billy]

With no voltage / current on the base of Q1 the transistor won’t conduct, so no signal will flow through it

Can’t see your DC jack wiring properly are you actually getting 9. 24v on the pcb not sure what you mean by source have you taken your reading on the pcb 9v and ground pads

If that’s the case and you are getting power to the pcb I’d begin by checking the components around the transistors R3 and 4 etc

Your transistors could obviously be faulty depending on where you got them I can see you’re now using sockets for Q1 but if they were soldered in intially like Q2 they may have been damaged

Are both transistors 2N3904

 

 

[Billy]

There’s a few ideas for combination wiring here

Wiring Examples – Standard, Series, Combo, Buff N Blend, Easy Order & Tone TwEQ

 

[Billy]

Seeing as you’re a Celtic bhoy Dan

I’ll overlook that comparison of toilet roll and one of the mighty Glasgow Rangers scarfs on this occasion only, but with all this panic buying madness I’ll take the toilet roll mate

And seeing as you’re probably taller than desperate Dan in real life I’ll expect a fairly large one

 

[Billy]

Haha cheers Ray

I think once this madness is over young Dan should send u a wee flagon over

When he messaged me with the initial idea I think coz we talk pedals a lot he thought I’d know, sadly my answer was not got a clue!

Dan was getting desperate so I said don’t be desperate………Dan

Calm yourself down with a slice of cow pie and post it on the GPCB forums I told you to join ages ago and hopefully Wikie1 who I think will know how to do it will take pity on you like he does with me and give you some of his great advice and knowledge

[Billy]

Aye did I not also say its a few bottles of the good stuff too?

I’ll come round and collect them for Wilkie no problem Dan

[Billy]

The values in the parts list are what I’d use

The parts list is drawn up specifically for GPCB improved circuits

[Billy]

Defo agree with Cybercow we cant see any solder on a good few pads on the component side you sometimes get it coming through which is an indication its melted enough if not enough heat is applied the solder will sometimes be ball shaped and chalky inside meaning it doesn’t have a good connection between the solder pad and component leg

So I’d expect there to be a few dry solder joints upload an image of the solder side too

Also take your IC pin voltages which may give us an indication of your problem area

[Billy]

Nice looking build great idea too separating the boost

I only ever wire the input to ground if I have to

I’ve never actually had to do it with any GPCB build

The only time I did was with a script phase 90 build on an etched board adding pulldown resistors on both input and output didn’t cure the switch pop but putting a link between lugs 1 and 6 did the trick

So I dont do it unless I need to

I do however always ground both input and output jacks although rare jack nuts can come loose and with the 3PDT boards its only a little neat wire across

[Billy]

Both R11 and R19 come from VR (voltage reference) which would be half the supply voltage around 4.5v

VR originates from the junction of R17 and 18 the voltage divider, all the VR points on the schematic should have a voltage of around 4.5v half the supply

R19 is pretty close and R11 way off even though they are both fed from VR so you’d expect the voltages on them to be the same, that would make me think that the cause of your problems could be a dry solder joint or wrong value on the resistor R11 that or a dry solder joint at pin 5 IC1B

As you know dry solder joints are often the cause of problems so perhaps try reflowing all of your solder joints especially the IC sockets with the IC’S removed, simply reheat the solder for 2 or 3 seconds allowing it to flow

I personally would normally check voltages at all the VR points indicated on the schematic starting at the bottom legs of R17 and 18 the voltage divider junction up to both sides of R11 and 19 and into pins 3 and 5 of the IC

I’d also check your VB points are all around 5v just to get used to using and checking schematic voltage information even though we know they are with your 4.91v on pin 1 of the PT2399 that tells us that IC3 is working correctly its all good practice and learning

[Billy]

Check R11 is definitely a 1K and not a 110R both have the same colour bands read the opposite way

The voltage on IC1B pin 5 is way off it should be around 4.5v coming from VR through R11 all pins except 4 ground and 8 power should be around 4.5v

Some of your PT2399 readings are a little off pin 9 for example with 0v so check C1 solder joints have a good connection

I’d compare the voltages and use the schematic to check those areas where your voltages differ taking into account the difference in power supply,  yours looks like it’s 9.18V

Make sure your PT2399 is firmly secured into it’s socket

[Billy]

Here’s some discussion on it

https://www.diystompboxes.com/smfforum/index.php?topic=90489.0

http://tagboardeffects.blogspot.com/2012/09/heathkit-ta28.html?m=1

And Mark is indeed spot on

https://sites.google.com/a/davidmorrin.com/www/home/trouble/troubleeffects/heathkit-ta-28-fuzz-booster

[Billy]

Nice looks great definitely my absolute favourite fuzz

You should post it in the show off your GuitarPCB and win post in this forum

[Billy]

Great glad it’s sorted

If you haven’t already make yourself an audio probe They’re cheap and easy to make and use

Probing your circuit cuts down debugging from hours to minutes most times

It’s a great tool

[Billy]

Ben I wouldn’t give up just yet

I’d use this to learn how to use an audio probe

They’re cheap to make and easy to use and probably one of the best debugging tools

This circuit’s fairly simple so it shouldn’t take long to find where you loose audio

Read the audio probe explained PDF in the guides page

The GUIDES PAGE – Mandatory Reading for all!

If it was working initially apart from the buzz then as you said it’s more than likely a ground issue if you are using the 3PDT board that would also need to be grounded you can run a wire from the one knob fuzz pad marked S5 to any ground pad on the 3PDT board

Post a nice clear picture of how it is now so we can have a last look it is definitely savable so as I say although it’s frustrating it’s well worth continuing to debug you’ll learn a lot which will stand you in good stead for future builds

I’ve built hundreds of pedals complicated and simple and they don’t always fire up first time I’m currently having problems getting a super simple fuzz face to sound right

[Author]

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