canon pro 1000 repair

[hashwood]

Hello, I am looking for some advices on repairing a canon pro 1000?

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Canon PRO-1000 – looping, 5C13/5C14/5100 after service work (MC-20, purge unit, HMS, encoder)


Symptoms (chronological):

• Initial fault: “Maintenance cartridge full (MC-20)”.
• After clearing that, got 5C14 (non-ejection detected) and intermittent paper jam with no paper.
• Printer often stuck on “Processing… please wait” with repeated cleaning/priming and carriage oscillation ~10–15 cm on the right side.

What I did:

• MC-20 / counters: Hardware-wrote the EEPROM to clear the MC-20 status. Later physically drained the MC-20 (it weighed 531 g, then climbed to 599 g during loops). (I will replace with a new one, as it's cheap)
• Purge unit / waste path: Cleaned wipers, capper and spittoon; verified pump direction; primed the waste lines (spittoon → pump → MC-20) by rotating the pump CCW so it actually moves fluid to MC-20.
• Capper/wiper: Capper leaves a uniform wet imprint; wipers clean; cam cycles correctly.
• Encoder system: Thoroughly cleaned the encoder strip (especially right 10–15 cm) and the carriage encoder sensor slot; confirmed band runs centered in the sensor and is dry.
• Carriage rail: I removed the carriage; the upper rail was loosened. Realigned it using the factory emboss marks/“sights” (as per service manual) so rail height is back to spec and parallel, then retightened progressively.
• Head Management Sensor (HMS): Removed/cleaned the HMS window/lens, platen area in front of it, and reseated the harness. Tried centering, then slight up/down adjustments in its slotted mount.

Errors seen:

• 5C14 earlier (cleared after cleaning/priming).
• 5100 after reassembly (carriage positioning).
• After long oscillation, 5C13 (HMS position adjustment error).
• Odd behavior: the printer booted when HMS was unplugged, but later also looped even with HMS unplugged—so the failure is borderline/intermittent.

Current status:

• With everything assembled, the machine sometimes boots, other times loops on the right and eventually throws 5C13.
• Capper imprint is good; pump moves waste; MC-20 weight increases during cleaning; encoder strip/sensor are clean and dry; CR-HOME appears to switch.
• HMS looks physically clean; harness reseated; height/rail re-aligned.

Ask / next checks:

1. Any known HMS harness failures on PRO-1000 that cause intermittent 5C13/5C14? Worth replacing HMS + cable as a set?
2. Tolerance tips for HMS slotted adjustment or carriage upper rail height that typically clear 5C13?
3. Other causes of right-side carriage looping after ~30–60 s even when encoder looks good (e.g., relay PCB, CR-HOME alignment spec, pinion grub screw slipping)?

Any pointers to lock this down are appreciated. I also made a video