Roland FR-7X uneven bellows operation

[Gremlin]

I recently purchased a FR-7X. The push-pull bellows effect is not equal. When equal force is applied, the sound is much louder when closing the bellows than when opening them. I read a similar post on this site which resolved this issue on a Fr-3X by calibrating the pressure sensor using the process provided by Roland in the troubleshooting section of the FR-3X manual. Unfortunately, this issue is not addressed in the FR-7X manual. The thread indicates the calibration process for the FR-7X was once posted on the Yahoo Users Group, but Yahoo shut down all user groups in 2019. Could someone please advise me on this process? Thanks

 

[lmschgo]

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I found this post from the former Roland Yahoo Users Group, posted in 2015: “Pressure Sensor Calibration Procedure” for equalizing the audio level for each bellows direction.
I do not know if the instructions given for resetting the 7X's bellows are still correct today. So, proceed with caution.

 

[JerryPH]

They are... there has been zero development or changes in near a decade.

 

[JIM D.]

Have you tried restoring the factory defaults ?? The instructions are on page 94 of your manual.
If this doesn't correct it, you will have to take it to a Roland tech. The procedure involves removing the grill and putting the FR-7
in the 'test mode' and adjusting the pressure sensor to "O". A tech can perform this procedure in less than an hour.
The process is called " Pressure Sensor Calibration".
The process does not require parts replacement only a labor charge.
All the Roland models from the 1x to 8x with pressure sensor problems use this procedure for correction.

 

[Gremlin]

Thank you for the link to the thread in the old Roland users group. My accordion showed an initial calibration value of +36. At this level, you could turn up the volume and hear faint tones when playing the keyboard even when the instrument was sitting on its feet with the bellows strapped shut. I followed the procedure provided in the link and adjusted the calibration to zero. This resolved the problem and really improved the playability and feel of the instrument. Given the position of the potentiometer between the speakers, I imagine that the calibration could drift over time due to vibration. Thanks again!