JX-3P Issue
2013-02-16 by Nick Bell
Hi all, wonder if anyone has experience with these?
After sorting out noise & other problems as per my last post, I have another issue.
The problem is on channel 6, the saw wave is slightly quieter than on channels 1-5, it also sounds a bit more buzzy. This is for both DCO 1 & 2. Square waves are ok on both DCO's.
IC104 (in this case IC604..& so on) op amp, TR107, TR108, C113, C115 all deal with the waveform conversion from square to sawtooth. Considering both DCO1 & 2's sawtooth are both affected then do I assume IC604 is dying as this deals with both of the DCO's square to saw conversion, via C113, TR107 etc.
Worth mentioning is that
there were signs of capacitor leakage, this has been cleaned now and caps replaced in this area. Also, as I think would be expected from this, when the sync is engaged on certain patches, all sorts of pitch problems occur when channel 6 is activated.
Am I barking up the right/wrong tree here with my limited knowledge? Any thoughts most welcome.
Service manual here http://fa.utfs.org/diy/jx3p/jx3p_schem.htm
Thanks, Nick