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MB-6582 Problem: Puch buttons don't work


gtxdude
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Greetings. I am asking the collective for help in troubleshooting a problem on my newly constructed MB-6582. None of the push buttons on the CS work.

This is what I know:

I have been over both boards with a magnifier; no shorts, bridges or rotten solder joints that I can find. All the chips are plugged in with the correct orientation and none are overheating.

I am running the MB6582 hex file from this zip: midibox_sid_v2_041.zip

After power up the LEDs in the matrix blink in a pattern. Then the display shows the default patch and 10 or so LEDs light in what looks like the default configuration.

At this point most of the rotary encoders work but NONE of the push buttons change anything.

I have been over the CS PCB with an ohmmeter. None of the switches are shorted closed and measure closed when pushed. None of the steering diodes on the switches are shorted and measure correctly when forward biased.

Power rails are the correct voltages and look quite with a scope.

The LED test program does not light any of the LEDs. The square wave test program did work.

A display plugged into CPUs 1-2-3 shows “Ready.â€

With out a schematic I am at a loss as how to proceed from here. Can anyone suggest where to look next. I have spent several hours trying to figure this out and I must admit that I am out of altitude, airspeed and ideas.

Any help would be much appreciated.

Gtx

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The only thing I can come up with is that you maybe have your buttons oriented at 90 degrees of how they should be. There are no frontpanel schematics publicly available as far as I know, but this file comes really close for the frontpanel at least: http://www.mb6582.org/plans/MB-6582_CS_PCB_Color.pdf

I hope you can check your button orientation with that file. Take another look at the orientation of the diodes too, a special remark has been made about them in the troubleshooting guide here: http://www.midibox.org/dokuwiki/doku.php?id=wilba_mb_6582_control_surface_construction_guide. If everything works over MIDI, and your encoders work as well, it can really only be your buttons and/or diodes (as the encoders use the same DIN registers).

[edit]

addition; on the CS PCB all encoders are routed to the right 4 flatcables and all buttons to the 4 to the left. You could also check your flatcables, and maybe interchange some shift registers. Trace the working encoders to a working shift register and try that one in the place of one for buttons that doesn't work now.

Good luck!

Edited by NorthernLightX
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Hawkeye made an on building the CS.

Here is a picture with the right orientation of the switches.

The problem might also be on the base board as the DIN board is integrated there. Check if your 74HC165 are positioned correctly (U16-U20). Maybe swap them out.

Edited by Shuriken
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