Good day folks. Today, I came across something kinda special, which I haven't worked on before: a Roland RD100 electric piano. It was just sitting there in the shop covered in dust, no doubt having been ravaged and then abandoned by my oh-so-skilled co-worker. I actually remember seeing him struggling with this thing and I recall briefly witnessing the problem too: some of the notes play distorted. I'll try plugging it myself and maybe do some captures for you to hear for yourselves, but let's just say it sounds....bad.
I haven't actually dug into it myself yet, so this is mostly a generic discussion to kill some time and maybe learn something in the process, especially since I lack the most important tool to diagnose audio stuff: a scope !
I managed to grab the service manual - it's as simple as I expected: a PSU and some chips communicating back and forth. The block diagram on page 7 comes in handy to hopefully work out where the distortion may be happening. Unfortunately, most of these chips are dedicated and impossible to find, so I doubt this is fixable in the long run, but still...worth giving it a shot. If not, it could still be used as a MIDI controller I guess.....
I'd say the amp section on the "jack board" to the right is fine, since most notes play OK - if there was something wrong here, ALL notes would sound off. My money is on that "XP" chip (IC2) on the main board to be honest.
I haven't actually dug into it myself yet, so this is mostly a generic discussion to kill some time and maybe learn something in the process, especially since I lack the most important tool to diagnose audio stuff: a scope !
I managed to grab the service manual - it's as simple as I expected: a PSU and some chips communicating back and forth. The block diagram on page 7 comes in handy to hopefully work out where the distortion may be happening. Unfortunately, most of these chips are dedicated and impossible to find, so I doubt this is fixable in the long run, but still...worth giving it a shot. If not, it could still be used as a MIDI controller I guess.....
I'd say the amp section on the "jack board" to the right is fine, since most notes play OK - if there was something wrong here, ALL notes would sound off. My money is on that "XP" chip (IC2) on the main board to be honest.
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