Pro 10 Green problem! Solved!!

[Thommo]

G'day folks, first post here(unfortunately)

I've built up the Pro 10 Green and it is working nicely up until I push the gain up to around 3 o’clock, where it starts to kind of pulse as the signal decays. Below 3 o’clock is fine. 3 o’clock to max gain the pulsing is present.

I've uploaded a quick vid of the problem to my YouTube channel.

No mods or substitutions to the BOM have been made.

Cheers,
Thommo.

 

[BuddytheReow]

Have you verified all correct components have been installed? Solder bridges? Visual inspection (Chuck's law) is the first and probably the most crucial step in troubleshooting and can identify >75% of any potential issues. Possibly a shoddy capacitor? Can you post some pics as well of both sides of the board?

 

[zgrav]

when you get the pulsing with the gain turned up, does it change if you turn down the level of the signal going in to the pedal? Does it change if you are plugging directly in to the pedal or are going through one or more pedals in front of it?

posting detailed pictures of each side of your board will help others respond.

 

[Thommo]

Apologies, I did sub a couple of values on this board. I was thinking of the Pro 10 Blue for some reason. I used 4k7 for the 5k1 resistors And 47k for the 43k resistors.

I haven't posted in a forum for a very long time, so I'm a bit rusty, lol!!

Dropbox

www.dropbox.com

Dropbox

www.dropbox.com

I've done a bit of audio probing and I think the issue is coming from the gain stage. The gain pot has the clean signal on lug 1 and the overdriven signal, with the pulse on lug 2.

The pulse is there either straight in or behind other effects. It's also constant when not playing.

 

[Thommo]

Also getting clean signal on the right side of the 120pF cap and overdriven signal on the left side of the same cap.

 

[music6000]

R8 = 820R - Silver, Red, Black, Black, Brown , You have 680R - Blue, Silver, Black, Black, Brown !

Here is a Resistor Calculator.
Click on Bands for 5 Bands :

Resistor Calculator

Resistor Calculator is an App developed by CherryJourney to help the user find the value of a resistor.

resistor.cherryjourney.pt

 

[Thommo]

Ok, got it sorted. Sounds sweet!! Corrected the 820r resistor, thanks music6000.

The main problem would’ve been the handful of 22uF caps I had put into the 2u2 cap drawer.
Three of those made it onto the board, instead of the correct value.

Thanks for the replies, I appreciate you taking the time to do so

Cheers,
Thommo.

 

[music6000]

Ok, got it sorted. Sounds sweet!! Corrected the 820r resistor, thanks music6000.

The main problem would’ve been the handful of 22uF caps I had put into the 2u2 cap drawer.
Three of those made it onto the board, instead of the correct value.

Thanks for the replies, I appreciate you taking the time to do so

Cheers,
Thommo.

Watch out for .47uF, 4.7uf & 47uF Electrolytics also!

 

[caiofilipini]

Never trust labels, trust your DMM/LCR!

 

[Feral Feline]

Hi @Thommo, you can mark the thread "solved" now!

Another great mystery solved. I learn so much reading the trouble-shooting threads.

 

[Thommo]

Hi @Thommo, you can mark the thread "solved" now!

Another great mystery solved. I learn so much reading the trouble-shooting threads.

Cool, didn't know I could do that!!