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Questions: 5/11-05.
LCD problem
- The DSUB9 connector to the LCD had a bad connection or short-circuit so I cant get any numbers on the display now (worked well before)
- measure every connection for connectivity. End-to-end measurement is best ( relevant LCD pin to onboard pinheader - or DSUB9 if assembled controller is clamped ).
- document exactly your measurements (using pin numbers, colors, measured resistance). Also, link to docs you used in the first place.
- measure neighboring connections for shortcircuit. Also check againt GND (LCD metallic case)
If you apply some hotmelt after testing (at the DSUB9 and where the wires enter the LCD) and use good clearances, it's unlikely to cause problems later.
Repair display
Would it not be a god start to replace the IC1 with a new IC to fix the display
NO !!! SMD unsoldering is 5 times harder than making a proper LCD cable. Make a proper LCD cable first.
- Answer: I made a new display include wiring so of course all the connections are checked.
- I think the problem may be found in the PCB but maybe it is not possible to measure the component there is bad or is there something I can do?
- unfortunately, there is no simple establised way to debug a possibly damaged board. Disable the stepper and test the S259 3..6 outputs (mdh36, mdh46, mdh56, mdh66 commands to reset, and mdhb6, mdhc6, mdhd6, mdhe6 to set), even possible with assembled ECM. Outputs 1 and 2 should work too (available on the LCD header), not sure about outputs 0 and 7.
- You can document how initially connected the bad LCD, so that might help
- FACT
- There is light in the display. But the light is only 2 LEDs, quite independent from the main logic.
- Tried to replace with a new display include wiring and sub D but same negative result
- it would first make sense to make sure the new LCD + wire is correct (with another genboard?)
Remember that the most common mistake is forgetting the LCD contrast. (a 2k4 - or around - resistor between LCDpin1 GND and LCDpin3 contrast). If LCD shows nothing (neither squares nor garbage) this is the problem, almost for sure.
