weak early Ibanez CS-9

[fattheadd]

Hey, wondering if anyone can help. I've got a really early Ibanez CS-9 that is only partially functioning. I've got my mate to put it on his 'scope and it seems that the chorus part of the pedal IS functioning but it is barely oscillating, it hardly registers at all. Is there anyone out there who has a schematic (I've seen this one http://www.freeinfosociety.com/electronics/schematics/audio/pictures/ibanezcs9.gif  but I could really use one with test points!) or has an idea where in the pedal I should be looking? Let me know if if any other info is needed. Any help would be much appreciated, Many thanks to you kind folks!

[runmikeyrun]

access forbidden to that link...

[fattheadd]

So sorry! Please try this one  http://elektrotanya.com/PREVIEWS/45612216/23432455/hangszer/ibanez/ibanez_cs9_sch.pdf_1.png
Let me know if it's not working either:)

[R O Tiree]

First attack for me would be finding out what voltage you get at pin 8 of one of the TL072 opamps, or pin 7 of the 741 opamp.  If that's OK (9V), look at the other power supply - output from the 7805 (5V).

After that, use the second link you posted and get your friend to scope all the points marked "CP" and then a number.

CP1 ... square-wave clock pulses. Scope might not have enough bandwidth to see this.
CP2 ... 4.5V or thereabouts.
CP3 ... 5.0V
CP4 ... same signal as input - should be unity gain?
CP5 ... same signal as input, but with treble frequencies boosted
CP6 ... same signal as CP5, but might be a little clipped if the input signal is large
CP7 ... same as CP6 - this filters out the very high clock frequencies and shouldn't affect the tone very much.
CP8 ... output from the delay chip.  If the scope has enough bandwidth, you might see little, tiny steps in this signal
CP9 ... voltage ramping up and down slowly
CP10 ... as CP9, but between 0.7 and 1.0V (I think)
CP11 ... 9V
CP12 ... same as CP8, but with the "steps" removed.  Signal might still be a little jagged, though.
CP13 ... With no input signal, this should read just about 0V. With an input signal, should be the same as CP12
CP14 ... With no input signal, I think this should go to 4.5V, With an input signal, you should see square waves at the same frequency as the input (assuming a sinewave input).
CP15 ... With no input signal, this should float at about 4.5V. With an input signal, it should go to 0V (I think)
CP16 ... With the effect engaged, you should see the delayed signal as at CP12. With the effect disengaged, this should float at 4.5V or so.
CP17 ... With the effect engaged, this should float at around 4.5V. With the effect disengaged this should go towards 0V
CP18 ... With the effect engaged, this should be the original signal plus the delayed signal chorusing.  Previously mentioned treble boost at CP5 is removed. With the effect disengaged, this should be exactly the same as the input signal.
CP19 ... With the effect engaged, delayed signal inverted. With the effect disengaged, it should float at around 4.5V
CP20 ... With the effect engaged, original signal plus inverted delayed signal chorusing. Again, treble boost seen at CP5 will be removed. With the effect disengaged, this should be exactly the same as the input signal.

I think I got those all right. If there are any discrepancies, please let me know.

[fattheadd]

Wow, that's fantastic, thank you so much! I'll let you know how I get on with it