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Motor fader diodes


LO
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Hi

Ive almost finished my MF module  :D

The core is working with the MF firmware & the motorfader board is complete except for the diodes which are mounted next to the fet drivers(tc4427's). I am a bit confused as to which way around they should be mounted (duh!)

Im using the new PCB layout from the Ucapps site,  There are 4 diodes after each of the TC4427's I have set them up so the ends of the diode's with the line point toward each other. Is this the corect way??

If I have them the wrong way will I damage anything?

Thanks

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OK I tried hooking it up to the power! (No smoke or flames phew!)

Its receiving the data from my computer as the LCD display is showing the level rising and falling in time with the software fader.

But there is no movement of my fader; there is however a small noise coming from the motor it sounds like its trying to work! I tested my power supply to the fader (only one connected at this stage) while running it measured only 2-4V even when the adjustment pot was maxed out! It was calibrated to 8V when the motor wasnt running.

I think that my wall adapter is not good enough (12V 300mA I know it should be 1A but thought it would be ok since only one MF is connected.) Has anyone else had any experience with this? Just before I go out and buy a new adapter!

Or perhaps it is the way my diodes are arranged?? Maybe someone could post a close-up picture of the diodes correctly arranged??

Any help appreciated ;)

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first check the diodes, if they aren't connected in the right direction, the fader will not move.

I think that this pictures explains more than 1000 words ;-)

mf_diodes.jpg

And check the voltage behind the LM317 during the motor is running. It should be stable and shoudln't go down under load.

Best Regards, Thorsten.

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OK I think I had my LM317 backwards (it now faces the same way as your one in the photo!)

Im am now using a 16V AC wall adapter, but it measures 24V dc after the bridge rectifier! is this too high? (if so what AC Voltage should I be using?)

Even with 24V DC running in to the LM317 it still only outputs 6V (with the maximum pot setting) I have double checked the values of the components. Any thoughts on what is going wrong???

Thanks

LO

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mmmmm....  motor faders are working!!!

Frank,

I too was getting midi overruns, it seems to be related to the supply voltage to the MF board; with the 10K pot the adjustment is very touchy but the overruns stop when the voltage set correctly think I may have to swap back to the 1K pot, and try something else.

Do you use Panasonic faders? perhaps the panasonic faders need a slight firmware change to the internal speed values? this is a bit beyond me tho:)

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Hi Frank and LO,

my motorfaders (16 alps at two cores and mf´s with a 11V/1.25A powersupply for each of them) are working

great without any of the described problems.

You both should try to change back to the 1k trimmer and instead replace the 240 Ohm with a 100 Ohm. At least it should be easier to regulate the voltage this way. I don´t know if this cures your midi problems.

BTW, does any of you have any problems to configure the mf by sysex?

Axel

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Hey Axel, thanks for the info. Lo, are you using Panasonic faders and testing with only one fader wired up?, cos i'm using panasonic and tested with 1 and 2 faders wired but with the mentioned problems. Thorsten did mention that he never tested with 2 faders and running it this way might overload his interrupt routines.

So i'm gonna try to wire up all 8 faders and apply Axel's resistor change with 1K pot and see how it goes.

Later

Frank

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Update: I was able to reproduce the MIDI Overrun problem with a direct feedback (MIDI Out->MIDI In). Normaly this shouldn't hurt. I will try to find the root cause tomorrow. It isn't a performance problem, but a bug somewhere in the firmware (I hope that only MIDIbox MF is affected ;-)).

Best Regards, Thorsten.

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Finally I found the bug - the "second level fader handler" did call the MIDI learn routine sometimes, although this routine should only be activated within the MIDI Learn submenu. This error is fixed in v1.002 - Frank: now it should work in your environment :)

http://www.ucapps.de/midibox_mf/midibox_mf_v0002.hex.zip

Axel: I also checked the SysEx function, it works

Best Regards, Thorsten.

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