Need help trooubleshooting Ibanez TS5 mod

[Henry89789]

I tried modifying an Ibanez TS-5 Tube Screamer.  The changes I made are as follows:

OPamp changed to  JRC 4558D
R34 to 100 ohm
R35 to 10k ohm
D2 to Red LED
D3 to 1N4002
C11 changed from .22 tantalum to .15 uf metal film
C12 changed from .22 tantalum to .15 uf metal film
R18 to 2.2K
R19 to 10K
C10 to .1uf metal film
C8  changed from 1 uf electrolytic to 1 uf metal film
C13  changed from 1 uf electrolytic to 1 uf metal film

After finishing the mod I tried the pedal. After clicking the switch, the Led came on which was encouraging. But when I played the guitar through the pedal, the volume was substantially reduced. I turned the amp volume all the way up and you could hear the pedal work but again at a very low volume.  The effect even seemed to work. Switch the pedal off the the bypassed guitar comes through at normal volume.

Hopefully someone on this forum has experience modifying Tubescreamer or other similar pedals and has seen this problem before and can give me some ideas on where to start to fix this pedal.  Thanks in advance for any help with this problem.

[rockhorst]

Which schematic are you referring to?
As always: read an follow this, which you should've noted with already 46 posts
Build/use an audio probe.

My guess: bad solder joint or grounding issue. Check your IC voltages and double check all your ground wires. For instance: when reinstalling the board in the enclosure, you might have snapped a previously soldered ground wire at the DC jack. Happened to me the other day. The effect will work very softly, but it has no reference so voltages swing all over the place. Easy to miss, easy to fix.

[Henry89789]

Rockhorst:

Thanks for the reply. I am not sure what did it - I went back and checked all the solder joints (put the iron back on a couple that looked iffy); checked all the grounds: there were no snapped wires but I added a washer between the groundstrap and the coverplate to make sure there was a good connection - but now it works and sounds great with plenty of volume.