[sdiy] Roland JX8P maintenance

[Jacob Watters]

I think that the first step would be to open it up and clean it out. There
is often dirt and grime on the key contacts that cause trigger problems.
Don't use anything abrasive though - some contacts use a carbon coating
that you don't want to remove.

Then run the calibration if there is one in the service manual. It sounds
like there might be a gain staging issue when mixing multiple voices.

If you still have the distortion, then you need to start testing at
different points along the signal path to find where it is introduced.

On Thu, Oct 18, 2018 at 9:36 AM Steve <sleepy_dog at gmx.de> wrote:

> Hey list,
>
> I have a JX8P, which basically works, but has some issues.
> The case is ok-ish, apart from the beat up looking wooden underside, some
> of the screw holes not looking too trustworthy etc...
>
> Most of the membrane buttons barely work.
> Several of the keyboard keys have issues. Mostly not generating a note, or
> too low "velocity". One key is somehow mechanically bad, resting slightly
> angled. (I have not opened the whole thing yet).
>
> (@ Gordon: to prevent heart attack: I have not "re-capped" this thing, yet
> :D )
>
> I guess those are the standard problems and repair info to be found on
> those vintage synth info sites. (it's been a while since I'd seen such
> things...)
> What about this, though:
>
> Sometimes there is some notable distortion to the sound. I can't readily
> trigger it (so that I hear it anyway), but it seems more likely when
> several voices are on, not just one. The clearly discernable distortion is
> passing within 200ms or so.
> Is this a known thing with a known fix?
>
> Oh, and it's a version for the Japanese market with 110V. Is it much
> effort to convert it to 230V 50Hz? I'm currently using it with an external
> transformer to get it down to 110V, but it's quite bulky :) If a fitting
> transformer for 230V could be easily obtained and that's all to replace...
>
> As for usage:
> Is there any real advantage of having a programmer that connects to the
> special PG... port, over buying some Behringer MIDI box with a lot of knobs?
> (not that I'd pay those outrageous prices for one anyway ;))
>
> Feel free to mention other things I might want to be aware of! :)
>
> - Steve
>
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