in 2010 i discovered an issue with my Juno 60 and have as of yet to resolve the issue. i would really love to sort this out, it annoys me about every 7 years it seems and i get grumpy enough to post about it.
Symptoms:
when the PWM switch is in the LFO position, the square wave LED goes off and the LFO does modulate the pulse width, it's just erratic when moving the slider to change the amount compared to my Juno 106. when selecting MANUAL the LED returns and again the PWM works, but it's erratic as well while moving the slider, a digital glitching if you will. when selecting ENV, PWM works as expected. loading the factory patches does not solve anything, patch #11 uses PWM and it has the symptoms.
IF the HOLD and/or ARP is enabled, moving from either ENV or MAN to LFO turns off the ARP and silences any held notes, both LEDs for those go off. moving the switch from LFO turns those LEDs back on and pressing keys the functions works as before.
that the HOLD and ARP are disabled if running when switching the PWM mode select is the confusing part. IC40, a 4051 was changed by a previous owner, it now lives in a socket. i swapped it out, but it had no effect. IC18, another 4051 as well as IC1, a TL062 are part of the PWM circuit, but given the affect on the HOLD and ARP, i'm leaning more toward an issue on the CPU board, or maybe it's as simple as a bad diode allowing a reverse current to ground...
needless to say it's been like this for at least 14 years and i want to solve it. i believe i bought it like this, which annoys me even more.
i have a multimeter, an oscope and a very dusty EE. any suggestions would be helpful.
Symptoms:
when the PWM switch is in the LFO position, the square wave LED goes off and the LFO does modulate the pulse width, it's just erratic when moving the slider to change the amount compared to my Juno 106. when selecting MANUAL the LED returns and again the PWM works, but it's erratic as well while moving the slider, a digital glitching if you will. when selecting ENV, PWM works as expected. loading the factory patches does not solve anything, patch #11 uses PWM and it has the symptoms.
IF the HOLD and/or ARP is enabled, moving from either ENV or MAN to LFO turns off the ARP and silences any held notes, both LEDs for those go off. moving the switch from LFO turns those LEDs back on and pressing keys the functions works as before.
that the HOLD and ARP are disabled if running when switching the PWM mode select is the confusing part. IC40, a 4051 was changed by a previous owner, it now lives in a socket. i swapped it out, but it had no effect. IC18, another 4051 as well as IC1, a TL062 are part of the PWM circuit, but given the affect on the HOLD and ARP, i'm leaning more toward an issue on the CPU board, or maybe it's as simple as a bad diode allowing a reverse current to ground...
needless to say it's been like this for at least 14 years and i want to solve it. i believe i bought it like this, which annoys me even more.
i have a multimeter, an oscope and a very dusty EE. any suggestions would be helpful.
Statistics: Posted by blinky909 — Tue Apr 16, 2024 8:12 pm