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Re: jx-3p + not what to do when buying a jx-3p

PostPosted: Fri Aug 21, 2015 6:39 pm
by rhino
Another problem that seems to plague JX-3s:
On the panel board (the one with the controls and display) check at every screw that holds this board to the front case.
Look for small cracks that may have crossed some copper traces. You'll see where many very narrow traces make a 'detour' around the screw holes.

Re: jx-3p + not what to do when buying a jx-3p

PostPosted: Sat Aug 22, 2015 7:34 am
by elsquirrel
Thanks for the all info guys.

Gonna hold out until I have some decent desoldering equipment. I'm fairly confident (based on nothing ;) ) that I'll be able to fix the keybaord issues. As mentioned all keys work via midi so that narrows it down.

I was also able to clarify the problem with one of the voices. The saw and pulse waves for DCO 2 on VOICE 3, sound but the volume is very very low. I guess this means it's a vca related issue?

I'm going to keep working at this, hoping to learn some stuff on the way.

Re: jx-3p + not what to do when buying a jx-3p

PostPosted: Fri Dec 28, 2018 4:44 am
by elsquirrel
So i decided to pull this out and see what I deduce. I found some info where people had similar issues with dead keys in uniform patterns across the keyboard and had fixed this by checking the traces on the keyboard itself and repairing those. I went through with a multimeter and I couldn't find anything. All the connections seem fine all the way to the main board. I cleaned the as much gunk off as I could and rehaeted the soldered on the worst looking chips (breaking a leg off in the process - now repaired) and still no luck I don't have desoldering equipment, so probably will have it repaired.

Any other obvious things to look for before I sent it off for repair? There's nothing egregious. looking at the boards, I see no broken traces, although I haven't removed either of them

Thanks!


The issues as currently stands:

Lfo trig not working
brilliance slider not working

f1#
d2 a2#
f3#
d4 a4#

The saw and pulse waves for DCO 2 on VOICE 3, sound but the volume is very very low