Roland jupiter 6 repair

[angelothewolf]

Hi folks!
Im with this roland jupiter 6 on the bench, so far so good, then I get stuck trying to toubleshoot this issue. Aparently I have two voices missing. Looking at the waveform outputs of the CEM3340 chips I have two with no output at all. First I suspect the CEM chips, or the 4053 CMOS next to them. so I desoldered all of them and put sockets to swap them out. The two CEMs with no waveforms at the outputs are working properly in other positions, so they are not the issue aparently. then I swap IC34A (EHM-S226W83S) and IC41A (BA662), nothing changed still no output on that VCOs
Some idea??

jp6-page12.pdf

[Enzo]

Look at the control voltages coming into the voice, compare to those of a working voice. Any open R-packs?

The VCOs are controlled by the envelopes, a voice set to take a couple minutes to bring up sound, for example, will sound dead.

[angelothewolf]

Look at the control voltages coming into the voice, compare to those of a working voice. Any open R-packs?

The VCOs are controlled by the envelopes, a voice set to take a couple minutes to bring up sound, for example, will sound dead.

Thanks Enzo, Im getting mad with this sh*#$
this is my DC measurements comparision,

PIN# // working VCO

1 = -1.97V
2 = -4.39V
3 = -5.16
4 = -5.36V
5 = 1.62V
6 = -2.59V
7 = 18mV
8 = 3.33V
9 = 3.33V
10 = 1.66V
11 = 3.41V
12 = 0V
13 = 0V
14 = 20mV
15 = 0V
16 = 10V


PIN# // VCOA1 (no output waveform)


1 = -1.98V
2 = -4.38V
3 = -4.99V
4 = -9.2V
5 = 1.63V
6 = -2.57V
7 = 28mV
8 = 1.22V
9 =3.35V
10 =-1.21
11 =296mV
12 = 0V
13 = 0V
14 = 12mV
15 = 0V
16 = 10V


PIN# // VCOA2


1= -1.9V
2 = -4.3V
3 = -5V
4 = oscillating from 0V to 9V
5 = oscillating from 1.5V to 1.6V
6 = -2.56
7 = 37mV
8 = oscillating from 0V to 6V
9 = 3.40V
10 = oscillating from 0 to 3V
11 = 1V
12 = 0V
13 = 0V
14 = 232mV
15 = -444mV
16 = 10V





already tested the R packs and they are ok. also I have swapped the S2W83S and the 4053īs and replace IC20 4051 with no luck

[emielskey]

bumping an old thread because I have exactly the same issue right now on my MKS-80 (the rack nephew of the jupiter 6). also pin 10 of the cem3340 is -1.2 volts instead of 1.66.
Swapping the 3340's doesn't make any difference. sometimes the vco comes back to life, but only when the unit is still cold. (so maybe temperature related /faulty component).

still searching for the cause. did you have any luck finding it Angelothewolf? or maybe someone else has a suggestion?

[emielskey]

Found it! the culprit was a failing polyester cap, (c94 in the MKS-80) the one between pin 11 and pin 12(gnd) on the cem3340.

[andrew@lofly.com]

Hi just jumping in as similar topic…I am after a Roland S2W83S also called S226W83S… I am having difficulty sourcing…the rest of my J6 is going really well. Thanks if anyone can help.
Andrew