Hey everyone,
I’ve got a Roland D50 on the bench that has a weird issue. The unit makes a sound only after a key has been released. Happens on all keys, but works fine with an external midi controller attached. Already took the keybed apart and gave it a thorough cleaning.
Any ideas? I’ve never encountered a problem like this one before.
Hello,
If MIDI is working correctly, the problem is probably specific to the keyboard and therefore to IC1 or IC2.
If you’re lucky, it could be IC2 (RAM), otherwise it could be IC1, and then you’ll have to cannibalize another keyboard.
Do some research ; several Roland keyboards use this circuit.
Good luck!
Thanks! I’ll check to see if I’m getting any data on the RAM pins
In addition, it’s worth checking all the traces/components around the scan board.
These can get moisture damage so easily.
Finally got some time to get this one back on the bench in between other amps and synths. Gave it a good IPA cleaning and touched up some of the solder joints. Looks like I’ve got data (or at least some action) on all of the pins except for pin 19 on the RAM IC. That leads me to believe the RAM is working at least somewhat?
If there’s activity on the RAM pins, it means that GATE ARRAY IC1 is requesting it, which is good; it could mean that it appears to be working.
RAM pin 19 corresponds to address bit A10, a bit that may very well not be used.
However, the presence of signals on the data bus doesn’t guarantee the reliability of this data.
Since IC1 appears to be working, try replacing the RAM ; it shouldn’t be very expensive.
Got some RAM ordered, will report back when I get everything in and installed.
Just a follow up on this one. Got the RAM in the mail today and got it installed. This fixed the initial problem and the keyboard is working great now! Thanks for all your help everyone!
