The repair of Dbb541’s TS9

Eric_G

Senior Stratmaster
Jan 10, 2021
3,170
Quebec
Some of you may remember this thread:


In a nutshell, @dbb541 mistakenly plugged a 12V positive center power supply in its TS9… snap, crackle, pop and smoke… fried it. After providing a few pictures, it was obvious that the diode burnt. He replaced it to no avail, the pedal had more problems. @dbb541 was not enthused to troubleshoot further, so I offered to take a stab at it. I promised a report so there it is.

First I took a few pictures, always good to do if you’re going to work on something and not going to re-assemble it right after. Memory forgets, so photos references are quite useful.

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I then took everything out and started. Visual inspection.

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This little guy got my attention quickly, a 100uf capacitor that had better days…

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So went to my stash of parts and pulled a replacement. Didn’t have a 16V, so 50V will do. It’s a bit bigger but there was room on the board.

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Tried the pedal, but still no power, so I needed look further. I decided to replace the other 2 polarized cap part of the power circuit, and that did it. I had power again. I also noticed a white residue on a ceramic cap, so that B102 had to go as well.

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Plugged her in for testing, but all I had was white noise when the effect was engaged. That wasn’t a good sign. Did a bit of voltage measurement and discovered that the power divider circuit was not giving me the expected 9V VCC and 4.5V VREF.

Here’s the part of the circuit:

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R132 and R133 are 10K resistors that splits the voltage. Pulled both off and tested them. Both registered within tolerance, so that wasn‘t it. On this part of the circuit, C166 and C117 were also replaced as mentioned previously. So, something else was pulling current of the 4.5V VREF rail.

So I’ll save you a lot of troubleshooting steps, but let just say that it consisted of breaking the circuit for each component that feeds off VREF, until the expected 4.5V. Took a while but I got there. Sadly it was the component that I dreaded the most. the IC was fried and needed replacement.

Normally that would be an easy fix, on all my build, I socket the ICs, but Ibanez doesn’t. That part of the board is crowded and for those who tried it before desoldering an IC is a pain. Easiest way is to snip the legs as long as possible and then remove the pins one at the time. Lucky enough, my cutter were small enough to reach in.

Pulled it off, cleaned it up and soldered in a socket. Pin in a JRC4558, and check the voltages again. Success, the VREF was back to 4.5V. But would it work ?

Plugged her in my amp and plugged in my guitar. First test, no more white noise, played some strings, and voila…. She screamed again.

I boxed her back up, and will be shipping her back to @dbb541 this week.

It took me a while, as some of you know, I got a new puppy at home. She’s more quiet now, so I was able to attack it today.
 

Eric_G

Senior Stratmaster
Jan 10, 2021
3,170
Quebec
Good stuff! I have no real idea about the inner workings of a pedal so I admire your work and dedication:)
I can’t take all the credit, I reached out to my DIY pedal community for pointers. I still consider myself a newbie at this… this was a great learning experience.

I’m slowly getting better tho. Building and troubleshooting your own stuff is one thing. Working on this pedal was something else.
 

dbb541

Senior Stratmaster
Oct 14, 2010
1,521
Eugene
I can’t take all the credit, I reached out to my DIY pedal community for pointers. I still consider myself a newbie at this… this was a great learning experience.

I’m slowly getting better tho. Building and troubleshooting your own stuff is one thing. Working on this pedal was something else.
Eric,

Thank you for doing this, I am sure you have a lot of time invested.

Every once in a while you meet a really cool person in these online communities. This is one of those times. you’re a good dude!

Dan
 

Eric_G

Senior Stratmaster
Jan 10, 2021
3,170
Quebec
Eric,

Thank you for doing this, I am sure you have a lot of time invested.

Every once in a while you meet a really cool person in these online communities. This is one of those times. you’re a good dude!

Dan
Well thanks for your kind words, but really thank you for the opportunity…

Today I researched a bit further where I could add a true reverse polarity protection. If the power input was mounted to the enclosure and wired to the board it would be easy. But it’s PCB mounted, so a bit more tricky.

Plan is to cut the board trace with a sharp Exacto knife and jump the trace with a diode from A or K.

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If your OK with this, I’ll get her done.
 

Eric_G

Senior Stratmaster
Jan 10, 2021
3,170
Quebec
@duzie and @simoncroft , thanks…

My point of view is simple, we saved a pedal from the landfills and @dbb541 gets to rock on for a little longer !

The bottom line is almost all pedals are fixable, and I’m willing to help anyone who’s patient. There are plenty of members here that would do just the same, if not on a pedal, an amp or a guitar.
 

dbb541

Senior Stratmaster
Oct 14, 2010
1,521
Eugene
Well thanks for your kind words, but really thank you for the opportunity…

Today I researched a bit further where I could add a true reverse polarity protection. If the power input was mounted to the enclosure and wired to the board it would be easy. But it’s PCB mounted, so a bit more tricky.

Plan is to cut the board trace with a sharp Exacto knife and jump the trace with a diode from A or K.

View attachment 584471

If your OK with this, I’ll get her done.
I’m cool with whatever you want to do. Thanks
 

Eric_G

Senior Stratmaster
Jan 10, 2021
3,170
Quebec
As suggested by @Triple Jim, I put in the protection diode. As mentioned above, I cut the trace with an exacto, confirmed the trace was no longer offering continuity, install the diode and tested the pedal. @dbb541 should no longer be able to fry the pedal.

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Now word of advice, when you pack a pedal to return it to its owner, make sure you re-install the knobs :D

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J-Mart

Senior Stratmaster
Jul 17, 2020
1,290
Tx
Eric,

Thank you for doing this, I am sure you have a lot of time invested.

Every once in a while you meet a really cool person in these online communities. This is one of those times. you’re a good dude!

Dan
When I first read your post, he was the guy i knew would get her going again.

Good show @Eric_G .... kick ass
 


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