Octave Cat help needed...

Pulling out your hair? Don't know what to do or where to go? Ask in here.
Forum rules
READ: VSE Board-Wide Rules and Guidelines

If your Help request has been solved, please edit your first post in order to select the Image Topic Icon to let others know your topic has been solved.
User avatar
WhinyLittleRunt
Active Member
Active Member
Posts: 478
Joined: Fri May 19, 2006 1:41 am
Location: CT

Octave Cat help needed...

Post by WhinyLittleRunt » Thu Apr 23, 2009 8:39 pm

Here's an interesting one...

I don't know how much people know about these other than they're supposed to be an "Arp Odyssey knockoff" which I really don't see being the case, but anyway...

We seem to have lost VCO2. Just prior to that the keyboard was producing the same note across all octaves. I disassembled it and reseated all the connectors and when I put it back together it was working the way it should again, but still have no second oscillator. A few weeks back was the last time we used it and everything was working ok. It hasn't been on since then until last night. I downloaded a service manual but I think I got the wrong version - this is a first rev Cat. Other than this there are some switches that need obvious cleaning but could anyone point me in the right direction in resolving this oscillator problem?
I like vintage synths....

User avatar
hfinn
Expert Member
Expert Member
Posts: 1197
Joined: Fri Dec 10, 2004 3:21 pm
Gear: http://soundcloud.com/heath-finnie
Location: Boston
Contact:

Re: Octave Cat help needed...

Post by hfinn » Fri Apr 24, 2009 12:20 am

If you ever get to Boston I could probably sort it out for you.

Steve Jones
Active Member
Active Member
Posts: 565
Joined: Wed Apr 23, 2008 10:40 pm
Real name: Steve
Location: Sydney
Contact:

Re: Octave Cat help needed...

Post by Steve Jones » Fri Apr 24, 2009 5:51 am

Check IC 33, old CMOS is often failure prone. Otherwise, if it was having keyboard problems, maybe the "2nd voice" circuit is faulty.
Synthesizer service tech since 1982.
Synth parts and service, Sydney Australia.

User avatar
WhinyLittleRunt
Active Member
Active Member
Posts: 478
Joined: Fri May 19, 2006 1:41 am
Location: CT

Re: Octave Cat help needed...

Post by WhinyLittleRunt » Fri Apr 24, 2009 4:53 pm

Thanks, that's a good start.

Is there a service manual floating around though that isn't the SRM version?
I like vintage synths....

User avatar
WhinyLittleRunt
Active Member
Active Member
Posts: 478
Joined: Fri May 19, 2006 1:41 am
Location: CT

Re: Octave Cat help needed...

Post by WhinyLittleRunt » Wed Apr 29, 2009 9:06 pm

Is there a service manual for the first Octave Cat, pre SRM?
I like vintage synths....

Steve Jones
Active Member
Active Member
Posts: 565
Joined: Wed Apr 23, 2008 10:40 pm
Real name: Steve
Location: Sydney
Contact:

Re: Octave Cat help needed...

Post by Steve Jones » Wed Apr 29, 2009 10:57 pm

I have only ever been able to find the SRM version. I don't know how different the SRM is to the pre-SRM, I have repaired a Kitten using the Cat SRM diagrams, so there doesn't seem to be much difference within the family.
Synthesizer service tech since 1982.
Synth parts and service, Sydney Australia.

User avatar
WhinyLittleRunt
Active Member
Active Member
Posts: 478
Joined: Fri May 19, 2006 1:41 am
Location: CT

Re: Octave Cat help needed...

Post by WhinyLittleRunt » Thu Apr 30, 2009 5:42 pm

Thanks Steve -

It turned out we actually did have schematics for the original octave, but you're right - I'm not sure how much they differ. My understanding was they just revised the boards for SRM models?

At any rate, I took your original advice and went ahead and replaced IC33, LM1458. This thing is a beauty to work on because all the IC's are socketed, and it made sense to just swap the chip and see. That didn't work though :(

I'm not all that good at following schematics but I try :) What's happening is there is no sound from VCO2 at all, but with all audio sources down, I can hear bleedthrough from VCO1 only. We validated this was coming from VCO1 by playing with the fine tune knob. I'm not sure how to trace the VCO circuit to find the fault. Will I need an oscilloscope for this?
I like vintage synths....

Steve Jones
Active Member
Active Member
Posts: 565
Joined: Wed Apr 23, 2008 10:40 pm
Real name: Steve
Location: Sydney
Contact:

Re: Octave Cat help needed...

Post by Steve Jones » Thu Apr 30, 2009 9:20 pm

The SRM version must be quite different then, I am looking at the SRM schematic, and it shows IC33 to be a CD4043, not an LM1458 which is an op-amp. Do you have a scan of the non-SRM schematic that I can take a look at?
Synthesizer service tech since 1982.
Synth parts and service, Sydney Australia.

User avatar
WhinyLittleRunt
Active Member
Active Member
Posts: 478
Joined: Fri May 19, 2006 1:41 am
Location: CT

Re: Octave Cat help needed...

Post by WhinyLittleRunt » Thu Apr 30, 2009 9:51 pm

Yes, I'm sure I can get that to you. I'll email it.
I like vintage synths....

User avatar
Sir Ruff
Synth Explorer
Synth Explorer
Posts: 3519
Joined: Tue May 09, 2006 11:55 pm
Gear: Two persimmon modulators and a frequency adjudicator.
Band: Ruff in the jungle
Location: Philadelphia

Re: Octave Cat help needed...

Post by Sir Ruff » Thu Apr 30, 2009 10:07 pm

I can't add anything as to where the osc has gone, but as far as the "same note across the keyboard" problem, that was probably directly linked to a short being caused by the boards not being grounded properly....

I have an a-rev cat that was doing exactly that-the board is lacking the pcb sealing stuff (I guess cos it's old), so the trace was directly touching a screw or something after I opened it up and them put everything back.

I know that doesn't help with the osc 2 issue, but at least you know there was nothing inherently wrong that was causing the single note problem.
Do you even post on vse bro?

User avatar
WhinyLittleRunt
Active Member
Active Member
Posts: 478
Joined: Fri May 19, 2006 1:41 am
Location: CT

Re: Octave Cat help needed...

Post by WhinyLittleRunt » Fri May 01, 2009 3:30 pm

Yeah, the grounding traces in some sections are bubbling up because they're old but we did solve that one not problem by reseating connections. Not sure why that would have made a difference but I'm not complaining... :) Still sucks without the second oscillator. The best news of all, as I mentioned before, was to find out all the IC's were socketed, That's such a huge help.
I like vintage synths....

rivas3
Newbie
Newbie
Posts: 67
Joined: Tue Aug 16, 2005 6:58 pm
Band: Bad Employees
Location: Huntington, WV
Contact:

Re: Octave Cat help needed...

Post by rivas3 » Mon Jun 29, 2009 8:58 pm

not a solution here...
but i have a-rev cat and also have this problem. the keys only trigger one pitch, and vco2 while still functional, fluctuates its tuning, like a ummm, dying cat....
still a great noise box. apply some spring reverb and you can get some squelchy effects like that of a vcs3.

User avatar
WhinyLittleRunt
Active Member
Active Member
Posts: 478
Joined: Fri May 19, 2006 1:41 am
Location: CT

Re: Octave Cat help needed...

Post by WhinyLittleRunt » Thu Jul 09, 2009 4:47 pm

rivas3 wrote:not a solution here...
but i have a-rev cat and also have this problem. the keys only trigger one pitch, and vco2 while still functional, fluctuates its tuning, like a ummm, dying cat....
still a great noise box. apply some spring reverb and you can get some squelchy effects like that of a vcs3.
Pull the back cover off and make sure the keyboard connector is seated in correctly. They are made with an odd number of connections and usually the last one is empty... make sure on the connector is actually seated matching up wire to contact... aka make sure it's on right. Someone could have pulled it off and reseated it wrong. I did...
I like vintage synths....

abrokenframe
Newbie
Newbie
Posts: 84
Joined: Fri Sep 29, 2006 9:40 am
Location: orange county, ca

Re: Octave Cat help needed...

Post by abrokenframe » Tue Apr 27, 2010 6:32 am

WhinyLittleRunt wrote:
rivas3 wrote:not a solution here...
but i have a-rev cat and also have this problem. the keys only trigger one pitch, and vco2 while still functional, fluctuates its tuning, like a ummm, dying cat....
still a great noise box. apply some spring reverb and you can get some squelchy effects like that of a vcs3.
Pull the back cover off and make sure the keyboard connector is seated in correctly. They are made with an odd number of connections and usually the last one is empty... make sure on the connector is actually seated matching up wire to contact... aka make sure it's on right. Someone could have pulled it off and reseated it wrong. I did...
i know what revas is saying...and its not the keyboard connector because i have tried it both ways. this keybed is really crappy.
ARPPiano,ax60,cz101,cz3000,evolver,p08,emulatorII,mirage,esq1,r100,ddd1,dss1,dw8/6000,er1,lambda,microkorg,poly6,poly800,sr120,rhythmace,d50,d70,d110,hs60,jd800,jp8000,juno60,jupiter8,jx8p,rs09,rs202,tr727,drumtraks,cs50,cs6x,dx7,rx5,dr880,rhodes,b2

Steve Jones
Active Member
Active Member
Posts: 565
Joined: Wed Apr 23, 2008 10:40 pm
Real name: Steve
Location: Sydney
Contact:

Re: Octave Cat help needed...

Post by Steve Jones » Tue Apr 27, 2010 1:59 pm

I have seen the "screw touching the board" issue in Cat's before too.
Synthesizer service tech since 1982.
Synth parts and service, Sydney Australia.

Post Reply