I’m wondering if anyone has ever come across this odd issue or if anyone has insight.
I’ve seen some comments here and there mentioning this issue (both d-50 and 550), but there were never solutions for it.
Symptom: D-50 only outputs a Mono signal on both the headphone and individual left/right outputs. The same patches work perfectly fine in stereo in the in the Roland Cloud plug-in.
Changed cables and headphones to be certain, but it outputs a mono signal regardless of this.
Reverb and chorus only come through as mono.
This unit had been serviced by someone at some point to fix key issues, but I’m yet to dive too deep to see if something wasn’t put back together just right.
Hoping it’s something as simple as a short somewhere causing both channels to merge into one.
I guess the question is whether it’s hardware or software related.
I’d do a good search for issues related to this first (you probably have) before attempting a probe into the hardware.
You’ve got the service manual?
Yeah I’ve got the service manual, so I’m going to start tracing it back from the outputs to try and understand this better.
There don’t seem to be any settings that would let you control this globally, but I’ve reset the whole thing to be sure.
None of the issues I’ve found online seem to match this too well or have proper confirmation that it’s the same thing. I don’t have any volume or crackling outputs or anything like that.
Tested it a bit more today and found that the Upper and Lower tones don’t split between the U and L outputs either, so I’m guessing it’s not just a reverb and chorus thing which is good for those IC’s! Not really finding many parts at the moment.
There are some test points for the Upper and Lower signals, so I might check those to see if they are at least separate there.
I haven’t really had to do much fault finding at the component level before, so this will definitely be a learning experience
It’s the same signal throughout - out of the DAC is a Mono Signal that goes into an analogue switch uPD4066 and gets send to the two individual signal paths UPPER and LOWER.
Hence, to make a real “STEREO” signal the DAC stream would have to be altered continually and at the same time the analogue switch to be changed from “UPPER” to “LOWER” and back continually at very high frequency (above hearing) which makes me think this is a software or user issue?!?
How it manages to output 2 signals from the DAC is definitely way beyond my understanding.
I did some more testing and probing today and have been able to come to a conclusion though!
TP1 and 2 don’t seem to show anything my multimeter can display. Don’t have a scope unfortunately :\
TP4 and 5 do show different voltages depending on the patch I’m using. Muting the Lower Signal showed there was nothing at TP4, which is a good sign and shows that the split signals work. TP5 had the Upper Signal and reacts to key presses and volume adjustments to the patch.
Had a bit of user error during this as the patch was using output mode 1 or 2 and had reverb enabled somewhere, which let a signal reach both test points. Definitely need to be using output modes 3 or 4 to test the discrete signals!
So both signals are separate when leaving the main board and reaching the bender board. It seems that once they leave the volume slider, both paths have the same signal. Guessing it’s the volume slider and a bad repair job it had at some point.
Looking closer at the after touch and volume sliders, the volume slider’s solder joints are shinier and a little messier than the duller looking joints of the after touch one.
Hoping this is the cause. Will report back if I get the chance to remove that board and check further.
Finally had some time to remove that volume slider. Turns out that despite the volume slider having two tracks/traces for stereo, the actual slider part was one that bridges the two tracks. I just cut that bridge and now it’s in stereo again!
