DLP MCU version troubleshooting, help needed
2014-12-22 by Marc.olanie@...
At last, I finished the « hardware » mods and wired the MCU… So far, so good. But the rig don’t seems to work.
I’m checking again and again all the different options, but don’t see where my gremlin is hidden.
When I’m starting the printer, after the initial check (without any carrier in the NPIS), the green led lights on, and after 4 seconds the feeder starts rolling without interruption during 60 seconds. All led are flashing at the end of the sequence.
If I place a carrier in the roller at this stage (before the motor stops), the carrier his “slurped” thru the printer, and stop moving when the end of the carrier has passed the NPIS (2 inches away from the npis). To eject the carrier, I have to “block” the npis with a piece of pcb or whatever, and press on the “run” button. The sequence ends with a "paper jam" alert only.
Voltage measurements on the mcu board
Pin 5 of the MCU goes low when no carrier detected in the NPIS, high when obstructed.
5 V is ok on pin 8 (5.02V, perfect)
Pin 6 is high, goes low after approx. 1 second and stay low during 3 seconds when “X” or “run” is pressed
Pin 7 is high, goes low after approx. 3 seconds and stay low during 4 seconds when “X” or “run” is pressed
Pin 3 is high, goes low after approx. 1 seconds and stay low during 4 seconds when “X” or “run” is pressed
Pin 2 is high (3.3v), goes briefly low when “X” or “run” pressed, then back to high, and briefly low again then high when “X” or “run” released
None of these timing are accurate (counting in my head, looking at the scope). If more precise measurement should be done, I’ll have to build a “poor man’s logic analyzer” with a cypress or an Arduino and it will takes a little more time
The two blue wires coming from J27-4 and J23-1 are left unsoldered (should I cut ?)
Hope this checklist is accurate enough to help find a clue
Tnks
Marc