Vintage Synth Repair

Quick update: Yep IC16 the BA662 is definitely bad so I need to source
 one or a BA6110 if I cant get them. The 6110 looks like it'll be ok
just has a different pinout.

Still looking into this 'voice' pre-set low volume problem..it's like
a fifth of the volume of the rest of the presets...the later module
boards had a trimmer fitted called VCF INV trimmer no. 31 that was
just to adjust the 'Voice' pre-set waveform..mine hasn't got it but
has the holes for a trimmer to be soldered in...maybe it's a factory
anomaly?

Oh yeh and Ive just found that the bender doesnt seem to work at all...

Phil.

--- In vintagesynthrepair@yahoogroups.com, "eggwheatis"
<eggwheatis@...> wrote:
>
> Hi guys, just calibrated my Jupiter 4 using the service data and a
> scope..well it all sounds great now except for the preset 'Voice'
> sound, it's very quiet. All the other presets are nicely balanced and
> sound correct except for this one's level. I've been back through my
> calibrations 3 times over and everything looks perfect. Anyone know
> anything about this?
> 
> Also I have a click at the start of one of the notes, I've traced it
> down to one of the module boards..and looking at the schems it looks
> like IC16 a Roland custom BA662 is the culprit. Is there a source for
> these anywhere? UK preferably..Also I've read conflicting information
> about the BA6110 being a suitable replacement..can't find a definitive
> answer though.. again any info would be helpful.
> 
> Thanks, Phil.
>