Q link replacement problem

I have tried to replace just the q link sliders. I changed them to 50k(originals are 10k) and weird things happend. Qlinks stopped working at all.
When I connect the connector on the right side(one next to sliders) my pads do not respond. But when i disconnect pads are responding and qlinks are still not responding.
Is there any solution? Should i desolder the newer qlinks? What is the connector next to qlink sliders for?

sadzik wrote:What is the connector next to qlink sliders for?

If you check the Service Manual, you can see where the connections go...



The QLink sliders/pots are at the top of the page, in the middle.

The Qlink signals go from the Operation-Left PCB into the Pad PCB, and are multiplexed with the Pad signals on the Pad PCB, before being sent to the Main PCB.

The other connector from the Operation-Left PCB sends signals from the After/Erase/Note Repeat buttons, across the MPC from the left side, to the right side, and connects those signals into the Operation-Right PCB that all the controls on the right side of the MPC are connected to, before being sent to the Main PCB along with those other signals. It also receives signals back through the same path to drive the After LEDs.


I don't think that substituting sliders with a different resistance value than the originals is ever going to work properly. Not sure if your issues are wholly related to that, or if you have problems relating to the soldering or circuit connectivity/continuity/shorting in some other way.

Maybe the multiplexer for the QLink and Pad signals doesn't work with the different value sliders, maybe there are soldering issues causing a short circuit that is causing the multiplexer to not work correctly, maybe something else entirely.

Thank you for exhausting info, every time.

Thing i did was : desolder new qlinks and solder them again. It worked.
However my sliders do not work properly now but they behave in acceptable way.
Maximum value is like 10-15mm from top of the slider. Also mid value is like in 10mm from bottom. Min value is correct.
When qlink is set from eg. tune -120 to +120 it is not so accurate, but when i set -120 to 0 difference is minimal than it was on original qlinks.

Thank you again for reply.

sadzik wrote:Thank you for exhausting info, every time.

Sorry to exhaust you with too much info!

sadzik wrote:Thing i did was : desolder new qlinks and solder them again. It worked.
However my sliders do not work properly now but they behave in acceptable way.
Maximum value is like 10-15mm from top of the slider. Also mid value is like in 10mm from bottom. Min value is correct.
When qlink is set from eg. tune -120 to +120 it is not so accurate, but when i set -120 to 0 difference is minimal than it was on original qlinks.

Yes, that is the problem I would expect from using different slider resistance values to the original, not getting the same range, either too little or too much, depending on if there is more or less resistance compared to the originals.