Io - A new MIDI retrofit for Jupiter 4

The Roland Jupiter-4 and ProMars Compuphonic Analogue Synthesizer
kimh
Posts: 2
Joined: Sat May 12, 2012 3:45 pm

Postby kimh » Wed Jun 20, 2012 9:42 pm

You can find him here:

http://midipolis.blogspot.dk/

i just ordered one a month ago - excellent fast service, product was perfect.

Kim

elektrovolt
Posts: 3
Joined: Sun Jun 10, 2007 11:52 pm
Location: Den Haag NL

Postby elektrovolt » Mon Nov 19, 2012 4:49 pm

just finished connecting the IO kit...
still not really stable here, sometimes a few glitches, noise is grungy sounding now, portamento is barely noticable and the unison-2 mode does not play polyphonic after some playing. powering off and on fixes this. the IO board gets quite hot after about 30 minutes.

Measured the PSU and voltages on the IO board, they are fine.

anyone has an idea?

Mr Arkadin
Posts: 27
Joined: Sun Jul 26, 2009 9:10 pm

Postby Mr Arkadin » Tue Nov 20, 2012 1:26 am

Do you have an early JP-4? Mine was the earlier model and there is a resistor that needs changing on the board that gets the portamento back - easy enough if you have someone adept at electronics. When I got the updated board I just got Laszlo to put the correct resistor in. He can tell you which one it is and the value so I would contact him in the first instance.

The other issues don't sound normal (although I have never felt the temperature of my Io kit).

elektrovolt
Posts: 3
Joined: Sun Jun 10, 2007 11:52 pm
Location: Den Haag NL

Postby elektrovolt » Tue Nov 20, 2012 9:26 am

yes, this is an early version. Laszlo asked this specifically and tested the IO before shipping. I must have made a wrong connection somewhere, the mod guide was not very clear because the wire colours are different.

I noticed the pin connectors are too short, I can't push the IO board all the way down. the components of the lower board are too high. this could cause the errors... I already put a piece of paper in between for insulation.

I have uploaded a few pics, maybe someone could check them...

https://picasaweb.google.com/1049652312 ... iter4IOMod

cheers

Mr Arkadin
Posts: 27
Joined: Sun Jul 26, 2009 9:10 pm

Postby Mr Arkadin » Wed Nov 21, 2012 10:39 pm

I don't know if this will help, but here are some photos I found of an open JP-4:

http://www.flickr.com/photos/23740030@N ... 070328852/

elektrovolt
Posts: 3
Joined: Sun Jun 10, 2007 11:52 pm
Location: Den Haag NL

Postby elektrovolt » Tue Nov 27, 2012 3:06 pm

looks like the white wire on the VCA is soldered on the other side of the resistor in my jup, as the resistor is placed the other way round. it works though.. see here: https://picasaweb.google.com/1049652312 ... 1218642722


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