Vintage Synth Repair

Hi group,

I'm new here and I apologize if I com running in immediately with a question:

I have a Roland Jupiter 6 which I bought when it cane out back in 1983. A few days ago I trid it out and after about two years in the cellar (humidity!) it hardly plays anymore. I will spare you all the details of shat doesn't work.

Anyway: I am located in Lisbon, Portugal but I travel twice a year to Germany, where I was born.

Last time had the JP6 repaired (some notes failed randomly - it was not key contact issue) I waited two years because of a chip which had to come from Japan (or so they told me...) - and I had it done by people who offiically represented Roland (300 kms up north in the city of Porto) at the time! I guess I need one of those vintage synth geeks who know their grear inside and out - and where to get the parts.

Questions: how hard is it to get chips for the JP6? Would you recommend bringing the synth to Germany (I will fly there for Christmas and New Year next time). Not that I think Germans are better at this - I just think there might be more of those - and thus perhaps easier to find.

I think the Jupiter 6 is an awesome synth. Not the phattest out there, but powerful, quite stable regarding tuning, and with a lot of punch and so extremely versatile that you can get extremely close to tons of classic analog sythns sounds. And it is extremely quiet. Almost no unwanted noise.

I'd loooove to have my baby back up and running.

Any pointer, any kind of help, would be very highly appreicated,

Thanks so much in advance,

Christian

>
> Hi group,
>  
> I'm new here and I apologize if I com running in immediately with a question:
>  
> I have a Roland Jupiter 6 which I bought when it cane out back in 1983. A few days ago I trid it out and after about two years in the cellar (humidity!) it hardly plays anymore. I will spare you all the details of shat doesn't work. 
> Anyway: I am located in Lisbon, Portugal but I travel twice a year to Germany, where I was born. 
> Last time had the JP6 repaired (some notes failed randomly - it was not key contact issue) I waited two years because of a chip which had to come from Japan (or so they told me...) - and I had it done by people who offiically represented Roland (300 kms up north in the city of Porto) at the time! I guess I need one of those vintage synth geeks who know their grear inside and out - and where to get the parts. 
>  
> Questions: how hard is it to get chips for the JP6? Would you recommend bringing the synth to Germany (I will fly there for Christmas and New Year next time). Not that I think Germans are better at this - I just think there might be more of those - and thus perhaps easier to find. 
>  
> I think the Jupiter 6 is an awesome synth. Not the phattest out there, but powerful, quite stable regarding tuning, and with a lot of punch and so extremely versatile that you can get extremely close to tons of classic analog sythns sounds. And it is extremely quiet. Almost no unwanted noise.
> I'd loooove to have my baby back up and running. 
>  
> Any pointer, any kind of help, would be very highly appreicated,
> Thanks so much in advance,
> Christian
>  
>  
>

>
> >>But upon further investigation, I determined that the LFO Freq Mod of OSCs 1, 2 and 3 was NOT working.<<
> 
> if you have the schemos, the next thing to do is find a local tech who can follow them better than you... :-)
> it sounds as though there's a failure of the IC-based switchgear associated with the mod routing.
> the switches under the LFO rate knob will create a path from the LFO onto the three oscillators using analog switch ICs...
> 
> um....
> 
> do the LEDs still come on? I will dig out the schemos for my LAMM this weekend & see if I can get you a bit closer.
> 
> duncan.
>

>
> >>thinking about it, & about 4016s generally, it's likely that this is one IC we're talking about. each has four switches internally, so one would be enough for three oscillators-worth of mod switching.<<
> 
> found the schemo at memorymoog.com. U13 is your culprit, I reckon, & if I'm right, you'll have lost pwm on osc 1 aswell.
> 
> schemo here:
> http://www.memorymoog.com/docs/
> 
> you want sheet 2 of the schematics pdf.
> 
> hth-
> duncan.
>

>
> >>Duncan, 
> I tried your suggestion, swapping out the U13 chip with one from another working mm+ but the problem remained. Any other suggestions?<<
> 
> U57, which is a 40174 latch on the demux board. it's the only other place where those signals & ONLY those signals are one one chip.
> 
> what threw me off its scent in the first place is that I assumed (NEVER assume with an MM!) that the same demux & latch would light the panel indicators. looks like it doesn't. 
> 
> there'll be a good reason for that, no doubt, but I haven't time to read the rest of the schemo now..... :-(
> 
> let me know how you get on.
> 
> d.
>