[sdiy] Jupiter 8 - all leds blink together....

[Travis Shire]

Clean/reseat any socketed chips. Looks like the CPU is in a reset (watchdog)
condition. This happens when it can't execute code as intended....so when it
detects something wrong, it resets. If it sees this condition continually,
it will reset (watchdog "barking") over and over. You may have ram or a
data/address buffer on its way out causing it. No way to tell until you go
over the CPU data/address lines with a scope and find something abnormal.
----- Original Message ----- 
From: "Gil W." <gil_we at yahoo.com>
To: <synth-diy at dropmix.xs4all.nl>
Sent: Saturday, December 08, 2007 8:49 AM
Subject: [sdiy] Jupiter 8 - all leds blink together....


> My JP8 has some kind of intermittent behavior.
> Sometimes it boots just fine, but every once in a
> while it will boot with all preset/bank leds blinking.
> When it works normally, it will let the leds "run"
> from the first bank to the last, four times, and then
> stops - ready to work.
> When the problem occurs, the leds will "run" two
> cycles, and then all flash together, and I can see the
> two LFO leds not working as expected - each LFO led
> should normally flash  at it set rate, but when the
> problem occurs they won't flash in cycles (but rather
> kind of randomly) and the led light is not on and off
> but just any level of light between dark and full
> lighting.
>
> I already tried to re-seat all connectors but no help.
> Any ideas ? Does the system normally "run" the leds 4
> times - one time for each voice module ? meaning that
> the controller had a difficulty recognizing and tuning
> voice board #3 ?
>
>
>
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