I am working on a Boss OC-2. It is a MIT and a schematic for the OC-2 MIT is harder to find. I have 3 different ones for the MIJ ones. My pedal does not have the BA634 chip in IC6 it has another MC14013BCP in both IC6 and IC7.

You may be able to help me solve this issue before I go much further.

I got the pedal plugged it up and it passes signal both on and off. When on the only thing that functions is the level OCT 1 and OCT 2 do not work. I read through a few post about people modding their OC-2 pedals and they seemed to run into this issue and would often replace their Op Amps and a few caps around it (but the caps could have been to filter the freqs)

Anyways I was thinking about swapping all the op amps including the MC14013BCP. I have IR9022 chips now and I heard a lot of people have success with swapping them for RC4558 and I have read that people swapped them with TL022(what they originally used in the OC-2 I think) and TL072's.

Do you know of something else I should suspect instead of the op amps?

I have a DMM but not a scope so I cannot scope the chips as many people recommended ...

ANY HELP IS SOOOO VERY APPRECIATED!!!
THANK YOU!
AFF

You can also e-mail me directly ... joshuaalan1@gmail.com

Thanks again!

Try this schematic:
http://www.freeinfosociety.com/elect...iew.php?id=135

The TL022 is noisy and slow but has low current draw. The 4558 is faster but has higher power consumption. It might help with tracking. Not sure.

I'm not too familiar with the IR9022. I wonder if a LM358 would work ok in there. The have a low current draw. I've used them in LFO's as a replacement for the TL022.

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Griffin Effects

I will look again just to be sure but I read that the TL022 and the 4558 are very close. I believe that the 9022 is a direct replacement that is no longer made. So with that when i looked at them yeah they were very close on their parameters but you are correct the 4558 was faster and consumed more power. I picked up some 4558's cheap ... like 10 cents a piece so I was thinking about using them and seeing if they would work. I'll solder in sockets first so i can try the LM358's as soon as i know they will replace them in this circuit. I am seeing that the octave and chorus pedal were using both the TL022 and the IR9022 chips ... but little info is available for that IR9022.

Thank You!!!

If you find more info please let me know I do appreciate the help!

Comparing datasheets, the 9022 and 4558 are very similar. Almost identical. You should have no problems swapping them out.

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Griffin Effects

So I replaced the TL022 with the 4558 chip and it sounds pretty good. It seems a slight bit different but not enough most would notice. I replaced the flip flop chip as well just to be sure so one of the 7 chips was failing and I figured it would be cheaper and easier to replace them all at one time.

So if you get an OC-2 and it is not operating like it should but you can tell the signal is passing just minus the effect ... i suggest upgrading all of the chips.

Good Luck!!!