Ibanez CP9 not compressing

[BDuguay]

I have a CP9 that passes signal in bypass and lights up when engaged but only the level pot seems to be working. The Attack Time and Threshold do nothing. I've probed the LM1300 and all seems fine there. Beyond that I'm lost. Are there any suggestions?
[url]http://www.dirk-hendrik.com/images/Ibanez_CP9.gif/url]
Thanks
B.

[BDuguay]

http://www.dirk-hendrik.com/images/Ibanez_CP9.gif

[Mark Hammer]

The fact that bypass uses the other half of the LM13600, and that your bypass is working fine, implies that the chip overall is not fried.

Verify for yourself that the pedal is actually producing an envelope voltage since variations in that will produce variations in compression.  I don't know what values to expect, but poke your meter probe at the junction of the two collectors from the mirror pair of 2SC2458 transistors.  You should at least see some sort of change there in response to transients.

[BDuguay]

I'm not sure I know what you mean Mark. I know the area on the schematic but what exactly should I be doing?

[BDuguay]

Using the guitar probe unit I built I get nothing at that connection.

[Mark Hammer]

If you're probing for an audio signal, I'm not so sure you're going to get anything you can hear.  You're going to want to use your DMM and look for something probably in the under-2VDC range.

[BDuguay]

-Dumb Question Alert-
-(minus)2VDC or 2VDC?
B.

[Mark Hammer]

I don't think your meter will care.

[BDuguay]

Didn't matter cuz I just measured and got the full 9.6VDC provided by my old trusted Boss PSA 120.
I take it that's not good right?

[Mark Hammer]

There shold probably be some DC, since what comes through the 24k and 100k pot is intended to influence the charge-up time of the 10uf cap.

Hmmm, is the parameter to measure the current?  Maybe some of the brighter, more edumacated types here can shed some light.

[BDuguay]

Uh-oh... When MC Hammer throws his hands in the air, that can't be good.
B.

[PRR]

[VintageGear]

I had two broken CP-9s over the years. Turned out that all I had to do on both of them, was resolder all the joints. I got some funny readings due to invisibly cracked solder joints. Actually fixed a few more 9-series pedals with that approach. Yeh its annoying but at least you know you got a good connection going on. And while your at it, inspect the board for damage, people tend to accidentally stand on the 9V plug, causing (in)visible defects in the board/traces.
If problem persists, then, well.. good luck!

[BDuguay]

V.G.,PRR-Thanks very much for chiming in! As for potential broken traces and such, it doesn't help much when, during troubleshooting, the whole piece falls off your bench resulting in the need to fix 6 broken traces!
Back at it today armed with this new info. Again, thanks!
B.

[BDuguay]

Upon checking it just now, I'm getting the right voltages on the 2SC2458 on the right (7VDC and 2VDC).
B.

[PRR]

Voltages around the 10/16 cap (middle transistor collectors and left transistor emitter) should all be high no-signal and go low with large signal.

[BDuguay]

I put my meter to it, set the Attack Time and Threshold pots to noon and hammered some opens chords and no change to the voltage reading of 9.6VDC.
W.T.Fudge?
B.

[Mark Hammer]

I'm not saying this is the right thing to do, but if it were me, I'd probably pull the 13600, install a socket, and see if the problem lies in the chip.  A lot of work for something that might not pan out, but those dual OTAs do fry sometimes.

[PRR]

> no change to the voltage reading of 9.6VDC.

Do you see how the circuit works? Use my snippet image.

Output signal comes in on the right. Is it getting to that point? Rightmost transistor makes two equal/opposite outputs, is there signal at both?

The pair in the middle idle "OFF" and turn-ON when signal hits 0.6V peak. When they turn on, they pull-down through the Attack pot, makes the 10/16 cap fall from 9V to some low voltage.

I'm thinking a bad signal path to the rightmost transistor, or a no-connection around the Attack pot.

[BDuguay]

I see the circuit snippet you posted but to answer your question, honestly no, I don't see how it works. Does that mean the test I did was wrongly applied?
I'm sorry and thankful for everyones patience and input.
B.