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[SOLVED] Debugging my MB6582 - Part 1 - Encoder issue


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Hello,

 

My MB6582 is at 95% level. That is: it does a proper job as an MBSIDV2 on the first core (with 2 8580), CS buttons  & leds all function properly.

 

The first issue I try to solve is:  the encoders don't work at all. Looking at the PCB's, I would say that the rightmost 4 74HC165's do the encoders, the left one does the button matrix. But when I pull out the  4 rightmost 165's, also the buttons stop working.  I swapped them in case one was toast, but to no resort.  Only with all five installed do the buttons work. 

 

 

My question: isn't this weird?  And if so, where to look for errors?

 

Edited by EsotericLabs
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There is an article in the Wiki that gives some troubleshooting hints.

 

Also, what you describe is not so surprising: encoders and switches share the same shift register chain, so if those SRs for the encoders are located before those for the switches, and you remove these SRs in the beginning of the chain, then obviously the switches are not scanned properly anymore either.

 

The rotary encoders are connected directly to the first four DIN modules on the base PCB (i.e. JD1 to JD4) as per the normal way of connecting rotary encoders to DIN modules. I guess the switches follow a matrix approach.

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Oh guys,  thank you  for the hints!

 

There is an article in the Wiki that gives some troubleshooting hints.

 

Will do the homework!

 

Also, what you describe is not so surprising: encoders and switches share the same shift register chain, so if those SRs for the encoders are located before those for the switches, and you remove these SRs in the beginning of the chain, then obviously the switches are not scanned properly anymore either.

 Yes of course, now I see!

 

  • check the interconnection between baseboard and CS with multimeter
  • check correct placing of resistor networks
  • check soldering of the 74HC165 sockets

Will test that too!

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