Roland JP8000 major distortion in all outputs

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Roland JP8000 major distortion in all outputs

Postby PWBakis » Mon Jan 28, 2013 2:43 pm

hi,

i have a Roland JP8000 synth that i am using for the past 13 years...

suddenly, few days ago, it started appearing major distortion in both stereo outputs and in its phone outputs.

the distortion is very loud and annoying. sometimes it comes and goes.

so, for short times, the synth plays fine and then the distortion fades in slowly....

also, during the times when the synth plays fine, (while before it sounded distorted), usually the former distortion fades out slowly until the synth sounds clean....

btw, two years ago, i had changed its battery and re-calibrated its ribbon and bender.

i opened the synth up and could not see any problem in ribbon cable connections. although i cannot check the solder joints if any are dry etc.....

any idea what this distortion could be?

thanks in advance for your help!

best regards, :)

Bakis.
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Re: Roland JP8000 major distortion in all outputs

Postby Phollop Willing PA » Mon Jan 28, 2013 7:16 pm

Try replacing the battery again. Maybe it burnt out faster than the last one. If it still does the distortion, then I'm out of my league with any other advice. I have a JP8000 too. For a VA, it's very nice.
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Re: Roland JP8000 major distortion in all outputs

Postby PWBakis » Mon Jan 28, 2013 7:27 pm

Phollop Willing PA wrote:Try replacing the battery again. Maybe it burnt out faster than the last one. If it still does the distortion, then I'm out of my league with any other advice. I have a JP8000 too. For a VA, it's very nice.


if the battery burnt out, how can it keep all the user patches?

i do not think its the battery.

anyway, many thanks for your offer to help! :)
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Re: Roland JP8000 major distortion in all outputs

Postby Phollop Willing PA » Mon Jan 28, 2013 7:31 pm

Don't know, good point. Good luck! Let us know how this was resolved, please, in case it happens to me and/or another JP 8000 user.
MOOGSig: Voyager/Theremin, ROLAND: JP8000/MC505/MC50/SH1000/Octapad1/RE 20, CASIO VLtone, KORG: Kronos73/Prophecy/MS2000R/Kaos Pad2/D3200/D888/SDD4000/M3, BOSS SP202/DR110, YAMAHA:CS40M/QX7/WX7/QY10, ARP Exp, MACBETH M5, FR ORB, SONNET, ALESIS SR18
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Re: Roland JP8000 major distortion in all outputs

Postby Yekuku » Tue Jan 29, 2013 1:21 am

If a factory reset doesn't solve the problem then it is a hardware issue.
Start by checking the power supply board, you should read +5V,+15V,-15V.
The problem could be after the DAC, you should check everything near the opamps on both the main and jack board.
There is a sound test that can be used in diagnostic mode in order to determine the faulty ICs but you need to have an oscilloscope.
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Re: Roland JP8000 major distortion in all outputs

Postby garranimal » Tue Jan 29, 2013 4:53 am

This may be a grounding issue. If memory serves, if the grounding pins aren't securely attached, have come loose, or have developed some oxidation then some of the nasty side-effects like those mentioned can occur.
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