Boss OC-2 octave Down 1 not working

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nunomaio
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Posts: 8
Joined: 12 Oct 2012, 00:19

Post by nunomaio »

]I got a second hand Boss OC-2 that was in a very bad shape. The box was very rusted on the outside through the edges, and on the inside some solders, mainly the main connections to jacks and secondary board were oxidized.
Before starting any work I plugged in the pedal and it works. Octave two and direct signal work, it's just octave one that is not working.
First thing I did was cleaning the board and remove the oxidized solders and re-solder again. After that I replaced the Octave 1 Pot (still not working). I then tried to trace the Octave Down 1 path and replaced the c29 electrolytic on the audio path, replaced IC4(TL022) (noticed that when IC4 is not present Octave 2 also doesn't work).
What I'm looking at is IC5(TL022) now and perhaps Q7(2SK30) and Q8(2SK30) but I'm really quite lost at the moment.

Anyone with any in-depth to where I should be looking at to find the problem?

Hope someone can help.

Here's the schematic:Image
Image

Here are the pics:
DSC_0055.JPG
,
DSC_0054.JPG
Here are the voltages for the IC's:
Also for Q7 and Q8 as they seem to be the only one's that are in the way of the Octave 1 path.

Input Voltage: 9.63v


IC1: TL022
1- 9.56
2- 9.56
3- 9.19
4- 9.63
5- 9.20
6- 9.20
7- 9.20
8- 9.63

IC-2 TL022
1- 9.04
2- 9.19
3- 9.20
4- 9.63
5- 9.21
6- 9.19
7- 8.91
8- 9.63

IC3 TL022
1- 9.04
2- 9.21
3- 9.20
4- 9.63
5- 9.21
6- 9.20
7- 8.92
8- 9.63

IC4 TL022
1- 9.56
2- 9.56
3- 9.21
4- 9.63
5- 9.20
6- 9.18
7- 9.18
8- 9.63

IC5 TL022
1- 9.53
2- 9.56
3- 9.63
4- 9.62
5- 9.62
6- 9.56
7- 9.53
8- 9.63

IC6 BA634
1- 9.16
2- 9.17
3- 9.62
4- 9.63
5- 9.63

IC7 MN4013B
1- 9.11
2- 9.15
3- 9.11
4- 9.62
5- 9.15
6- 9.62
7- 9.62
8- 9.05
9- 9.62
10- 9.05
11- 9.62
12- 9.11
13- 9.12
14- 9.62

Q7 (2SK30)
Drain- 5.19v Gate- 1.90/ 2.30v Source- 5.2v

Q8 (2sK30)
Darin- 5.2 Gate- 2.17/ 2.35v Source- 5.19v

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