MB LC motor fader problems

[greg19606]

Good Afternoon,

I been working on building a MBLC and can't seem to get the motor part of the faders working. The faders themselves report position to the computer but don't move when commanded. I also tried the test/calibration program and have the same result. I am using alps motorfaders but these don't have touch sensors. I have done the basic checks but I'm at school and don't have a scope or logic analyzer handy to more in depth tests. The only thing I can think of is that I dont have the touch sensor setting right, but I am not sure what the right setting would be. If anyone has any suggestions as to what I might check or adjust that would be a big help.

Thanks

Greg Griffith

[TK.]

The default mode (TOUCH_SENSOR_MODE 1) is sufficient for your case. Since the faders are even not moved by the calibration applications, the problem is probably located at the MBHP_MF module.

Check the voltages: you should read ca. 7.5V at IC1..IC8 pin Vss/Vdd - this voltage should be stable even if the application tries to move the faders. If the voltage is dropping below 7.5V whenever a fader should be moved, the problem is either related to your PSU, or to the LM317 based VR circuit (e.g. bad soldering)

Check also the voltages between IC9/10 Vss and Vdd pin, we expect ca. 5V

Whenever a fader should be moved, one of the two IN inputs (INA/INB) of the TC4427 IC will be activated (change from 0V to 5V) - one line for upward, another line for downward moves (I don't remember how they are mapped exactly)

This allows you to check the serial connection between MBHP_CORE and MBHP_MF: send a Pitchbend value at channel #1 with value 0 (e.g. via MIDI-Ox) - either IC1:INA or IC1:INB should be activated. Now move the fader manually to this position - the line should be deactivated.

Thereafter send the maximum pitchbend value, the other line should be activated until the fader has been manually moved to the top position.

If none of the direction inputs is activated, there is a problem with the 74HC595 chips or the SO/SC/RC line to the core (check soldering)

Best Regards, Thorsten.

[TK.]

P.S.: to check the digital control of the INA/INB inputs, it's probably easier to use the mf_direct_control application instead of sending Pitchbend events to MBLC - it allows you to set the pins directly by using 16 buttons (the first 16 buttons in the DIN chain)

Best Regards, Thorsten.

[greg19606]

Good Evening,

Thanks for the advice, after checking the items mentioned I ended up replaceing the of the 595's and it ended up working just fine.

I must have had a few bad ones around. Sorry about taking so long to get back, classes endedup getting in the way.

Thanks Again

Greg Griffith