I have a Roland RD 150 keyboard which I have owned since it was new in 2001. Recently I’ve noticed that when using the split feature, the lower keyboard has about a quarter of the output volume as the upper. It doesn’t seem to matter which instrument is selected, for example, when using the piano sound as the upper/right hand instrument, the volume is plenty loud, but when the same piano sound is assigned to the lower/left-hand side, it is very quiet, even when the lower volume slider is all the way up.
I have opened the case and checked all the connections, and everything looks good. This issue is also happening when using the headphone output, so I don’t think it’s related to the output jacks or anything specific to the amplifier. Anybody out there experienced anything like this, or have suggestions for troubleshooting?
Thanks for taking time to reply! Amazingly I stil have the original manual, and while I saw that part, unfortunately thats where the actual problem is.
Perhaps I worded it incorrectly in the post, but it used to be the case that if those two sliders were set at equal positions, then the upper and lower volumes would be equal as well. Now, in order to get equal volume, the lower slider needs to be all the way up, and the upper slider at say only an eighth to a quarter up, otherwise it completely drowns out the lower. It’s a workaround, but I’d love to figure out what the root cause is, and how to address it.
Additionally, it doesn’t matter which instruments are used, for example if the lower is acoustic bass and upper is piano, the piano is much louder with the sliders equal. Reverse that, with the acoustic bass set to upper, and it becomes the louder one with equal sliders.
Do you have this keyboard? Maybe you or someone reading this can confirm that if the two sliders are at equal height, the output is more or less the same for each instrument. I suppose there’s a chance this is normal and I’m just misremembering as I don’t use this feature too frequently, but it’s probably worth ruling that out.
Thanks!
Can you just clarify for me; if the keyboard is NOT split then the volume of all 88 keys are same - is this correct?!
Exactly. Split button off, there’s equal volume on any key, regardless of instrument. And also equal volume between instruments - to use the example of piano and acoustic bass, the bass will be equal to piano volume when toggling between the two. Once that split button is pressed, however, whatever is assigned to the left half becomes a fraction of the volume of the right. Hope that helps clarify, I’ll try to upload a video if this forum allows it (I’m new here 
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These two level sliders are not a volume button as per usual. They just transmit a voltage level to the CPU chip - it then makes the required digital setting to set the volumes. That can be getting confused for the CPU.
Can you do the following sequence please - do not touch any keyboard keys:
- Split keyboard
- Move LOWER VOLUME all the way to the top - then all the way to the bottom and then to the middle position
- Move UPPER VOLUME all the way to the top - then all the way to the bottom and then to the middle position
- now play one lower keyboard key and one upper keyboard key
What are the levels now?
Still the same, I’m at the piano now, I tried that procedure starting with both sliders fully down, fully up, and in the middle. Same thing, right side drastically louder than left. I understand what you’re saying though, I’ll keep tinkering along those lines. Definitely open to other ideas though. Thanks!
OK - let’s do a Factory Reset:
- Turn power off to the RD-150
- Push down and hold [PLAY] and [REC]
- Whilst [PLAY] and [REC] button pushed down turn power on
- After a few seconds the 7-segment display will show [Fct]
Now split and try
First thing I tried, sorry I didn’t mention that in the original post, but I did just do it again to be sure. No luck unfortunately
One thing I forgot - if in split mode and both LOWER VOLUME and UPPER VOLUME are at full level (all the way to the top) are the volumes still different or same?
When the sliders are set equally, the volumes are different, at the same ratio, no matter where the sliders are. I’d say the left is 1/4 to 1/3 the output of the right.
Have you got capability to open the unit to do measurements?
Opening it is no problem, I do have a multimeter but I draw the line at soldering, that’s where I decide to take something into the shop and let the pros deal with it 
Good - just to verify:
There is a cable going from the board where the sliders are to the main board.
Pin1 in the connector is GND, pin2 and pin3 are the two slider outputs.
Put the meter between GND and either of these two pins and measure what you see when moving the sliders - mostly interested in fully down and fully up.
Compare readings of the two - they should be the same.
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Sounds doable, I’ll get in there this weekend. Thanks for the help so far!
I’m sure it’ll make more sense when I’m actually looking at the board, but where will I be making contact with the multimeter? I’m assuming the cable needs to be plugged in so I don’t think I’ll have access to the pins directly
Not a problem, connectors are accessible from the top (see picture) - they all look like that except for the keyboard connectors - they are read and are a different type.
Ok, finally had some time today to open it up, two questions -
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I see the connector in the diagram has 9 pins, and the picture you sent has the same colors and configuration (pink, black, white, black, black, repeat) from the side of the plug nearest the edge of the board working inward, but I can’t tell which are pins 1-3. Would that be the pink, black, and white on one side, or the black, black, and white starting from the other side?
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I have access right now to the board labeled “Jack Board”. The other end of the connector goes to the board that all the buttons and sliders are attached to. Does it matter which end I test from? If I need to remove the upper board I will, but just want to confirm it’s necessary before I do.
Pic of the jack board and plug:
Pic of the upper board with the other end of the connector:
Picture was for reference only - just to show you how the connectors look.
For our purposes you want to check on the main board CN1 (main board is the almost square looking one - see pic below) - PIN9 is the closest to the corner.
On that CN1 you are looking to check GND-AN5 (pins 1-2) and GND-AN6 (pins 1-3)
Ok, thanks for the detailed explanation! I’m getting .015 volts with both pins 1-2 and 1-3. Does that seem correct? Apologies if I have the meter set incorrectly, here’s a pic for reference.
You want to use Volts DC, turn the unit on and then measure the points.
Slider up should read 5VDC, slider down should read 0VDC (or close to it) and slider in the middle should be about 2.5VDC.
Check either individually .
