My univox super fuzz pedal kit won't work

Started by snow123, March 09, 2021, 04:57:33 PM

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tl-ww-ext

I'm not really sure what you meant by 'regular 2n2222a's' when you mentioned the transistors previously, but it seems like if you are using 2n2222a's they should be oriented opposite what is indicated on the pcb.  That is, rotated 180 degrees from what you show in the last picture showing the transistors.  That's how they are in my working pedal, built from a GGG kit. 

Others who know much more about this can certainly correct me if I'm wrong on this.

T

duck_arse

page 4. please, it's time you took voltage measures on each of the transistors, and the supply voltage on the board, and posted them here.
You hold the small basket while I strain the gnat.

snow123

im thinking of getting a new pcb since i already have most of the other parts on hand.

snow123

ive also been working on 2 other projects (a phase 90 & a buffer) while doing this lol

snow123

Quote from: tl-ww-ext on April 07, 2021, 09:32:48 AM
I'm not really sure what you meant by 'regular 2n2222a's' when you mentioned the transistors previously, but it seems like if you are using 2n2222a's they should be oriented opposite what is indicated on the pcb.  That is, rotated 180 degrees from what you show in the last picture showing the transistors.  That's how they are in my working pedal, built from a GGG kit. 

Others who know much more about this can certainly correct me if I'm wrong on this.

T
the ones in the kit were pn2222a's so i swapped em out with standard 2n2222a's.

tl-ww-ext

#65
...pn2222a's so i swapped em out with standard 2n2222a's.

OK, I get what you're saying, but...  When I look up PN2222A vs 2N2222A, I actually see the same pinout, that is, reversed from what is shown on the pcb.  Here's a link: http://www.analogzoo.com/2015/03/beware-the-p2n222a/

Now, there are also P2N2222A's - note the '2' right after the 'P' that do indeed have a pinout opposite the PN2222A/2N2222A transistors.  If you were using P2N2222A, then I would say yes, they should be installed according to the print on the pcb.  FWIW I remember being getting very confused about the orientation on these and used sockets just in case.  Good luck,

T

bluebunny

You can always test your transistor if you're not sure about the pinout.  Use a dedicated tester (like a Peak DCA55) or the transistor tester functionality of many DMMs.  Or you can use the diode function of a DMM to work it out.
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andy-h-h

Quote from: snow123 on April 07, 2021, 04:43:11 PM
im thinking of getting a new pcb since i already have most of the other parts on hand.

Start fresh / new board  :)  pop that in a draw somewhere, forget about it and look at it again months later. 

snow123

#68
Quote from: tl-ww-ext on April 08, 2021, 09:11:16 AM
...pn2222a's so i swapped em out with standard 2n2222a's.

OK, I get what you're saying, but...  When I look up PN2222A vs 2N2222A, I actually see the same pinout, that is, reversed from what is shown on the pcb.  Here's a link: http://www.analogzoo.com/2015/03/beware-the-p2n222a/

Now, there are also P2N2222A's - note the '2' right after the 'P' that do indeed have a pinout opposite the PN2222A/2N2222A transistors.  If you were using P2N2222A, then I would say yes, they should be installed according to the print on the pcb.  FWIW I remember being getting very confused about the orientation on these and used sockets just in case.  Good luck,

T

yea i meant to say p2n2222a's

snow123

Ok, I got everything on the new board done except for the offboard wiring. How does it look?




I think it does need a bit of cleaning up as I had to replace some components that were burnt up or something

snow123

also, i had to use lead free solder since i ran out of leaded solder

andy-h-h

Quote from: snow123 on April 13, 2021, 06:04:53 PM
also, i had to use lead free solder since i ran out of leaded solder

Get hold of some flux if you need to resolder or reflow - makes a massive difference.   

Looking good, magnifying glass helps to check.  Good luck.     :icon_biggrin:

eh la bas ma

#72


You're getting the hang of it. I'd bet it's going to work this time... I see some suspicious spots with possible shorts, I circled them in red. A quick move with the soldering iron and it should be perfect.

Caution with germanium diodes, I learned on this forum that some russian made diodes can have the marking band on the + side. The glass body is very fragile and easily breaks when we bend the legs too close to the glass. They sound great though...
"One Cannot derogate, by particular conventions, from the Laws which relate to public Order and good Morals." Article 6 of the Civil Code.
"We must not confuse what we are and what society has made of us." Theodor W. Adorno.

andy-h-h

Quote from: eh là bas ma on April 13, 2021, 11:37:53 PM



Caution with germanium diodes, I learned on this forum that some russian made diodes can have the marking band on the + side. The glass body is very fragile and easily breaks when we bend the legs too close to the glass. They sound great though...

Diode polarity is not an issue with this circuit, as there's a pair both going to ground with alternating polarity.  Makes no difference.   

True though - Russian diode marking are the wrong way around and they do break easily.   

snow123

Ok, just finished everything, how does it look? I am kinda worried about the little scraps that are stuck in the enclosure












eh la bas ma

#75
Looks good ! I spotted a possible short though :


I would clean the enclosure with Q-tips or a toothbrush, these scraps may cause some shorts if they move on the circuit.

It doesn't change anything to the sound but many pedal builders like to shorten their wires as much as possible, to get a nice, clean, well-organized build. It makes it easier to fit in the enclosure and gives you some room to add pots and switches if you want to add some mods (diodes switch, bass knob...)

Edit: you can find some amazing exemples on this thread :
https://www.diystompboxes.com/smfforum/index.php?topic=36392.29200
"One Cannot derogate, by particular conventions, from the Laws which relate to public Order and good Morals." Article 6 of the Civil Code.
"We must not confuse what we are and what society has made of us." Theodor W. Adorno.

andy-h-h

Quote from: snow123 on April 26, 2021, 04:30:24 PM
Ok, just finished everything, how does it look? I am kinda worried about the little scraps that are stuck in the enclosure


So its working?   

snow123

Quote from: andy-h-h on April 26, 2021, 06:12:10 PM
Quote from: snow123 on April 26, 2021, 04:30:24 PM
Ok, just finished everything, how does it look? I am kinda worried about the little scraps that are stuck in the enclosure


So its working?

well i just plugged it in and static is coming out of the amp, nothing else is.

snow123

but the led is now turning on and off when it should!!

snow123

Quote from: snow123 on April 26, 2021, 08:37:20 PM
Quote from: andy-h-h on April 26, 2021, 06:12:10 PM
Quote from: snow123 on April 26, 2021, 04:30:24 PM
Ok, just finished everything, how does it look? I am kinda worried about the little scraps that are stuck in the enclosure


So its working?

well i just plugged it in and static is coming out of the amp, nothing else is.

and the trimpots adjust how much static gets through.