Quote:
Originally Posted by ortek_service
MM5745 National 78 4 10 Parallel Custom
MM5746 Semiconductor 78 4 9 Parallell Custom
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Been out of action a few day this week having had the Jab !
Hand a look at these controllers they are close, having done a bit more work on the keyboard the controller seams to work it terms of putting out the correct codes, apart from the fact some of the data lines go to -12v for 0 and other go to Zero for 0, all go to +5v for 1.
Not all the key switches are working some only give one output and others neither. looking on the web, there are no spares out there for the key switches that I can find. Having taken a key out and remove the sensor element the chip has just come away from the small circuit board picture on this site.
Key switch and mine below
There other option might be just replace the Hall Effect module put there is no reference to its part number, unlike older SD hall effect switches.