SOLVED PARENTHESES - Boost problem

[sixxtus]

Hi everybody !

I just finished building the PARENTHESES pedal, and I have a problem with the boost switch that makes the pedal silent. Distortion and Octave are OK but when I engage the Boost, then there is no more sound coming out anymore.
I checked the capacitors, the resistors, all OK, and then I realised that I plugged the BS170 transistor (Q6) upside down....
I fixed that by putting it the good way, but the problem is still there ...
Did I destroy that transistor putting it upside down ? O did I damaged other components in the boost section with that mistake ?

Thanks in advance for your help, and sorry for my sloppy English, I'm French !

 

[Cybercow]

Good, clear, close-up photos of the circuit board & wiring would better help us help you.

 

[sixxtus]

Hi, sorry for the late answer, no internet yesterday ...
So here are the pics.
As mentionned before, only the boost section is not working (no more sound when engaged). Q6 (BS170 transistor) was plugged upside down, I since fixed that but the problem is still there. The boost potentiometer seems to work because I can hear some background noise when putting it to max when boost switch is engaged.
I wonder if the Q6 transistor is damaged since I plugged it upside down ...

 

[KR Sound]

The transistor should be fine- installing it backwards won’t kill it. Put some covers or something on the backs of the pots so they don’t come in contact with the component leads underneath them, or pull them away while testing. I’d go back over your solder joints again as some look a little sketchy.

 

[sixxtus]

Thanks for your help KR Sound
There is a pad on the back of the pots, plus I bend them backward to be sure there is no contact with the board.
The joints are not perfect I know, I'm not the best with that, but they don't seem to be worse than the other joints on the rest of the circuit (distortion and octave), wich works fine.
I put the tip of a screwdriver on all of them, and get a hum, so aren't they all fine ? (Precision : I'm a total noob in electronic )

 

[sixxtus]

Any idea anyone ?

 

[Erik S]

I'm with @KR Sound - reflowing the joints associated with that part of the circuit seems like a good first step.

 

[sixxtus]

Thanks Erik S
I reflow all the joints in that boost section, problem is still there. I can hear some background noise when I turn up the boost pot to the max when boost is engaged, so I assume the footswitch and the pot are ok, the boost led is ok too.
I wonder if it could be a problem with one component that doesn't work... I'll buy another BS170 transistor to check that first.

 

[Erik S]

I just noticed you don't have covers on the back of your pots.

If the bare metal back of the pot contacts the soldered connections on the board you'll often get unintended circuit behavior.

You can try slipping a guitar pick in there or bending the pot away from the board and see if that makes a difference. If that helps you could glue a pick in there or some similar insulating material. Electrical tape does not work well, as the solder often pokes through when you tighten up the pots in the enclosure.

Sorry - disregard. Just saw the earlier posts on that....

 

[Laundryroom David]

Thanks Erik S
I reflow all the joints in that boost section, problem is still there. I can hear some background noise when I turn up the boost pot to the max when boost is engaged, so I assume the footswitch and the pot are ok, the boost led is ok too.
I wonder if it could be a problem with one component that doesn't work... I'll buy another BS170 transistor to check that first.

Mosfets like the bs170 are relatively sensitive to electrostatic discharge. Also, sockets are a pain. Make sure you have good contact of the transistor in the socket?

 

[sixxtus]

Thanks Laundryroom David for your help
I checked the position of that transistor several times to be sure it does have a good contact, no sound whatsoever... I can't get out of my head that since I plugged it upside down at first, it get damaged... I'll buy one or two at Muskiding with another pedal kit, just for not paying the postage only for 2 components

 

[comradehoser]

.....and welcome to the slippery slope of building more boards to obtain electronics to build your boards.

 

[Cybercow]

If you've re-flowed the solder joints, I suggest conducting a signal trace to find out where the signal dies.

 

[sixxtus]

.....and welcome to the slippery slope of building more boards to obtain electronics to build your boards.

 

[sixxtus]

All right folks, I just received a brand new BS170 transistor from Musikding to replace the one I initially plugged upside down, and ... It works !!!!

The problem was finally coming from that transistor....

I must say I'm very happy with the sound of that pedal, though I just had the time to play it for about 5 minutes yet... I will post a build report with more pics as soon as I can.

I wanna thank you all very much for your help and support, such a great forum and community !!!

The only (little) problem that I got is that I ordered a paragon kit with the transistor, but I received a paragon mini kit... I'm gonna see what Musikding could do to solve their mistake, because I think I prefer the standard paragon kit over the mini one, it looks like it's easier to build with more space.

What do you think, If you ever had the chance to compare these two kits ?

Once again thank you very much for your help and support !!!

 

[Laundryroom David]

All right folks, I just received a brand new BS170 transistor from Musikding to replace the one I initially plugged upside down, and ... It works !!!!

The problem was finally coming from that transistor....

I must say I'm very happy with the sound of that pedal, though I just had the time to play it for about 5 minutes yet... I will post a build report with more pics as soon as I can.

I wanna thank you all very much for your help and support, such a great forum and community !!!

The only (little) problem that I got is that I ordered a paragon kit with the transistor, but I received a paragon mini kit... I'm gonna see what Musikding could do to solve their mistake, because I think I prefer the standard paragon kit over the mini one, it looks like it's easier to build with more space.

What do you think, If you ever had the chance to compare these two kits ?

Once again thank you very much for your help and support !!!

Huzzah!