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JX-3P: Chorus trouble and broken presets?

Posted: Wed Apr 19, 2017 2:02 am
by jeff_l_sp
Disclaimer: I am a complete newbie when it comes to all things synth, and yes I know I shouldn't be buying old machines then...

Got a Roland JX-3P today, but there are some issues with it and I'm not sure how (if at all) they can be fixed. I thought maybe someone with more experience could know something here:

1) The Chorus effect seems to be permanently switched on, even though the button lights up and darkens just as one would expect. I also tried using the PG-200's switch to no avail. What is the most likely cause for this?

2) Moreover, I think the chorus is faulty: if I crank up the volume I am greeted by this nice swirly white noise:
Some presets have some crackling which goes away if I turn down the VCA's volume. I suspect this is also due to the faulty chorus: the previous owner added a mono out from the motherboard and there the crackling is gone. I did a topic search and there were some people on here reporting the same problem, but I found no instructions on how to fix this.

3) This is the most puzzling to me: Some of the presets sound completely busted, while others seem just fine! Here's an example of the A3 Organ 1 patch, which I don't think is supposed to sound that way:
I am completely lost here. Is the memory faulty? Most of the other presets sound just like they should, so I don't know where else to look.

I already opened the JX3P and the circuits look fine, no visible damage. Again, I have almost zero experience with synths, so I might have missed something obvious here.
Thanks in advance!

Re: JX-3P: Chorus trouble and broken presets?

Posted: Fri Apr 21, 2017 3:28 pm
by JeEA
Correct organ I does not sound right.
There is something wrong with Your jx-3p

Now i guess it sounds like that without pg-200 swichted on
and metallic selected ;-)

Maybe the memory needs a new battery. Now this being a preset
I guess it is In a ROM. So this alone is not it.

I used to have one many years ago.

How does the board look where the previous owner has added a mono out?