# Muzzle won’t power on



## Rando_calrissian (May 20, 2021)

I just finished the build but it won’t power on where should I start?


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## zgrav (May 21, 2021)

spend some time reading through the forum posts about troubleshooting pedals that don't work.  learn how to use your digital meter if you do not already know.  after you get an idea of the process that people use to help pinpoint PCB issues, and after you use the forum discussions to help you look at your wiring to see if you think it is done correctly, post a bit more information along with clear pictures of both sides of your PCB and one showing your wiring to the power and in/out jacks.

unless something obvious jumps out in those pictures, you will be asked to confirm part values, clean off any residue on your board, and to provide updates if any of those steps make a difference.


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## BuddytheReow (May 21, 2021)

Post some pics too. How do you know it won't power on besides no sound. The LED wont light up? Does it work in bypass?


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## Rando_calrissian (May 21, 2021)

Found the power issue it was a broken wire but now it seems as it is in  permanent gate mode and won’t open I will post pictures soon


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## Rando_calrissian (May 21, 2021)

Rando_calrissian said:


> Found the power issue it was a broken wire but now it seems as it is in  permanent gate mode and won’t open I will post pictures soon


It passes signal with no issue in bypass


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## Rando_calrissian (May 21, 2021)




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## Rando_calrissian (May 21, 2021)

Also the 2 2n3904s on the left side are getting pretty hot


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## ADAOCE (May 21, 2021)

It’s really difficult to see anything in that picture. Unfortunately sometimes you have to take it out of the enclosure to get better pictures. Are you sure those gigantic caps aren’t shorting anything?

also by permanent gate mode do you mean it is completely silent? Or does it make a little noise but still gating?

i don’t think the transistors are supposed to get hot that could be your issue. Before you start replacing parts I would really look it over solder bridges that may be shorting or cold joints


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## Rando_calrissian (May 21, 2021)

yes it is silent,

I’m currently going through the schematic and following with a signal generator so see where the signal stops currently at pin 17 on the that4301 I get a square wave at .8mv where at input I have 3v
At the output of that section pin 13 on the that I have 0


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## Rando_calrissian (May 21, 2021)

Rando_calrissian said:


> yes it is silent,
> 
> I’m currently going through the schematic and following with a signal generator so see where the signal stops currently at pin 17 on the that4301 I get a square wave at .8mv where at input I have 3v
> At the output of that section pin 13 on the that I have 0


Also pin 1 of the tl072 gives 0 voltage


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## Rando_calrissian (May 21, 2021)

Also the light stays on and won’t change no matter where the threshold is set


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## BuddytheReow (May 21, 2021)

Pin 1 for a tl072 is the input signal. There may be a short somewhere prior to that. Pin 8 will have in the input voltage so that should be around 9v


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## Rando_calrissian (May 21, 2021)

BuddytheReow said:


> Pin 1 for a tl072 is the input signal. There may be a short somewhere prior to that. Pin 8 will have in the input voltage so that should be around 9v


From the schematic it looks like a closed loop feeding into pin 5 of the that4301


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## Rando_calrissian (May 21, 2021)

Pin 4  on the that also has 0 output but pins 1 and 2 have signal in I’m feeding a 1k sin wave at 2vp
And pin 2 has 200mv pin 1 has 480 mv


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## Rando_calrissian (May 21, 2021)

Everything after that point has nothing


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## Rando_calrissian (May 21, 2021)




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## Rando_calrissian (May 21, 2021)

Rando_calrissian said:


> View attachment 12053


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## fig (May 21, 2021)

Did you use an LT1054?


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## Rando_calrissian (May 21, 2021)

Yes


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## Rando_calrissian (May 21, 2021)

Rando_calrissian said:


> Yes


Also my negative sources that should be -9v are reason -2.5v


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## Rando_calrissian (May 20, 2021)

I just finished the build but it won’t power on where should I start?


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## fig (May 21, 2021)

What is voltage at pin 5 of LT1054?


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## Rando_calrissian (May 21, 2021)

fig said:


> What is voltage at pin 5 of LT1054?


-4.2


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## fig (May 21, 2021)

Double-check the key jack wiring.


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## Rando_calrissian (May 21, 2021)

I followed the picture and the other forum post talking about it I believe it’s correct I’ll check again though


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## Rando_calrissian (May 22, 2021)

fig said:


> Double-check the key jack wiring.


Checked it over again and the key wiring is correct


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## music6000 (May 22, 2021)

Rando_calrissian said:


> Checked it over again and the key wiring is correct


Did you use TRS Jacks for key chain?, they look like mono jacks


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## Rando_calrissian (May 22, 2021)

music6000 said:


> Did you use TRS Jacks for key chain?, they look like mono jacks


Yes I used the ones linked on the bom page


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## music6000 (May 22, 2021)

Do you get Continuity if you put DMM test leads on solder switched tip & tip terminals on Sidechain jack?


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## Rando_calrissian (May 22, 2021)

music6000 said:


> Do you get Continuity if you put DMM test leads on solder switched tip & tip terminals on Sidechain jack?


Yes


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## Rando_calrissian (May 27, 2021)

I still can’t figure out why it’s not working. Anyone have a voltage list at junctions I can compare to


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## zgrav (May 27, 2021)

list the voltage readings you are getting on all of the pins for the ICs.
also confirm which IC pins have continuity to ground


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## music6000 (May 27, 2021)

zgrav said:


> list the voltage readings you are getting on all of the pins for the ICs.
> also confirm which IC pins have continuity to ground


Bofore going any further, Clean the PCB & Inspect your Solder Joints, very Questionable!


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## Rando_calrissian (May 28, 2021)

Ic3
1-8
-.02
-.02
.001
-2.637
.002
-.013
-.013
8.66

Ic1
1-8
1.989
4.646
.005
-3.096
-6.61
2.558
1.392
8.68

ic2
1-10
-.262
-1.385
-.836
-.332
-.285
-.404
-1.619
0
0
-2.615

11-20
8.67
-.287
-.286
-1.648
-1.62
0
-.295
-.411
-.259
.003


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## music6000 (May 28, 2021)

Rando_calrissian said:


> Ic3
> 1-8
> -.02
> -.02
> ...


The voltages are all over the place, Clean the board & check for Dry joints & Bridging, ie solder jumping onto another pad.
This is critical when buiding these circuits to Clean the flux residue off the PCB.
It will show any dodgy solder on the pads!
I use Electrical Contact Cleaner in a Spray Can on the Solder side directly.
You can use it in conjuction with a Toothbrush if you have trouble cleaning though it has not been needed with my Builds.

Cheers music6000


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## TSReppe (May 29, 2021)

Cleaning, reflowing them clean again would be my recommended first thing to do. If that doesn’t work I’d say it’s audio probe time. How are your skills at reading schematics?


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## Rando_calrissian (Jun 3, 2021)

Cleaning didn’t help anything but one major problem I see is that q2 is not receiving 9v from the rail as it is supposed to


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## Rando_calrissian (Jun 3, 2021)

Rando_calrissian said:


> Cleaning didn’t help anything but one major problem I see is that q2 is not receiving 9v from the rail as it is supposed to


It is getting .709 on the collector and .156 on the emitter


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## music6000 (Jun 3, 2021)

Rando_calrissian said:


> It is getting .709 on the collector and .156 on the emitter


What voltage are you getting at Pin 5 on the LT1054 ?


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## Rando_calrissian (Jun 3, 2021)

.156


music6000 said:


> What voltage are you getting at Pin 5 on the LT1054 ?


.156vdc


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## music6000 (Jun 3, 2021)

Pin 5 goes directly to the Collector of Q2.
What voltage is at Pin 8 of LT1054


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## Rando_calrissian (May 20, 2021)

I just finished the build but it won’t power on where should I start?


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## Rando_calrissian (Jun 3, 2021)

music6000 said:


> Pin 5 goes directly to the Collector of Q2.
> What voltage is at Pin 8 of LT1054


8.71vdc


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## Robert (Jun 3, 2021)

Pin 5 of the LT1054 should be around -9V.

More importantly, where did you get your THAT4301?   That doesn't look like a genuine IC.


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## Rando_calrissian (Jun 3, 2021)

The only place I could find them was eBay could that be causing all the issues?


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## Robert (Jun 3, 2021)

It's very likely.

Just for the heck of it, pull out the THAT4301 and then measure the voltage on pin 5 of the LT1054 again.


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## Rando_calrissian (Jun 4, 2021)

Robert said:


> It's very likely.
> 
> Just for the heck of it, pull out the THAT4301 and then measure the voltage on pin 5 of the LT1054 again.


Replaced the lt1054 and now I’m getting -6.68v


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## music6000 (Jun 4, 2021)

Remove the THAT4301 & see what voltage, you should be getting -9v!


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## Rando_calrissian (Jun 4, 2021)

music6000 said:


> Remove the THAT4301 & see what voltage, you should be getting -9v!


With the chip pulled it’s -8.35


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## music6000 (Jun 4, 2021)

That's more in line with what you are getting at Pin 8 of the LT1054.
What type of Power supply are you using?
THAT4301 seems to be drawing too much voltage!


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## Rando_calrissian (Jun 4, 2021)

Using a planet waves power supply but it seems as though my eBay that4301 is the issue and now I’m having trouble sourcing another


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## music6000 (Jun 4, 2021)

What country are you in?


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## Rando_calrissian (Jun 4, 2021)

music6000 said:


> What country are you in?


United states


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## Robert (Jun 4, 2021)

This is what the THAT4301 _should_ look like.      They're out of production and have become pretty hard to find over the past year.


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## Rando_calrissian (Jun 4, 2021)

From all my searching it doesn't look like I can get any at this time


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## Rando_calrissian (Jun 4, 2021)

Rando_calrissian said:


> From all my searching it doesn't look like I can get any at this time


Saw some post about alibaba clones that work but you have to order a minimum of 5 at 17 dollars each


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## music6000 (Jun 4, 2021)

I have used this site & Hector has always sent genuine parts.
Contact him to send a picture to be sure!








						THAT4301P20-I / THAT 4301 That Corp.,DIP20.
					

THAT4301P, THAT Analog Engine® IC Dynamics Processor. ThatCorp, DIP20




					www.retroamplis.com


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## music6000 (Jun 4, 2021)

Try this first, There in your country :




__





						Search that4301p, that4301p distributor|,buy that4301p, in stock,Darlington, Capacitor, find chips, electronic component, diode, Transistors, Sensors, IGBT, IC chip at utsource.
					

Search that4301p in Utsource,Utsource is distributor of that4301p, buy that4301p, in stock, new&original, and we also provide that4301p datasheets, pictures, and PDF.



					www.utsource.net


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## Rando_calrissian (Jun 4, 2021)

music6000 said:


> I have used this site & Hector has always sent genuine parts.
> Contact him to send a picture to be sure!
> 
> 
> ...


That’s 30 dollars is without shipping


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## Rando_calrissian (Jun 28, 2021)

Bit the bullet and it finally arrived but I’m still having issues the voltages are as follows ic1 tc1044

1-8
8.7,5.03,0,-3.313,-7.98,3.988,5.511,8.70

ic 2 that4301
1-20
0
.036
0
-.069
.885
0
-.439
0
0
-7.89
8.7
-0.002
0
-.440
-.440
0
.002
2.552
.001
0

Ic3 tl072cp
1-8
.005
.005
0
-7.89
.001
.001
.001
8.71


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