Canon Pixma MP640

Printers are based on mechanical processes but the actions carried out by an inkjet printer are determined by software running in the processor on the Main Logic PCB. Almost every aspect of printer operation is controlled by this software, including the printers ability to report faults through error messages.

# PIXMA-MP640 Logic Board Assembly & PE Sensor Board Assembly.

	Part	Description	Compatibility	Google	Prices
8-1	QC2-7678-000	Release Arm	MG5220 / MG6120 / MG8120 / MP640 / MP980 / MP990	10 results	$0.26 €0,22
8-2	QM3-3730-000	Inner Cover	MP640 / MP980 / MP990	8 results	$6.75 €6,08
8-3	WE8-6617-000	Ferrite Ring	MP560 / MP568 / MP620 / MP628 / MP640 / MP980 / MP990 / MX860 / MX868 / MX870 / MP876 / MX882 /MX886	16 results	$2.59 €2,56
8-4	QK1-5646-000	Card Slot Cable	MG6120 / MP640 / MP990 / MX882 / MX886	6 results	$0.32 €0,40
8-5	QK1-5831-000	PictBridge Cable	MP640 / MP990	6 results	$0.80 €0,94
8-6	WE8-6618-000	Ferrite Ring	MP560 / MP568 / MP620 / MP628 / MP640 / MP980 / MP990 / MX860 / MP868 / MX870 / MX876 / MX882 / MX886	6 results	$2.78 €2,74
8-7	QC3-1220-000	Ferrite Ring Holder	MP640 / MG5220	6 results	$0.74 €0,84
8-8	QC2-7976-000	Card Slot	MP620 / MP628 / MP640	4 results	$1.05 €0,94
8-9	QM3-6850-000	Card Control Board	MP640 only	7 results (of 14)	$19.63 €28,92
8-10	QM3-6886-000	PictBridge PCB	MG6120 / MG8120 / MP640 / MP990	6 results	$9.75 €12,44
8-11	QM3-6889-000	Main Logic PCB	MP640 only	10 results	no price €96,18
8-12	QM3-4413-000	PE Sensor PCB		27 results	no price €17,64
8-13	QK1-4984-000	PE Sensor Cable	MP640 / MP980 / MP990	7 results	$0.40 €0,40
8-14	QK1-4990-000	LF Encoder Cable		23 results	$0.40 €0,72
8-15	QC2-7490-000	GAP Cover	MG5220 / MG6120 / MG8120 / MP640 / MP980 / MP990	19 results	$0.53 €0,50
8-16	QC3-3584-000	Protective Sheet	MP640 only	7 results	$16.20 €2,12
8-17	QM3-6215-000	Wireless LAN Cable	MP640 only	7 results	$3.57 €4,58
8-18	QK1-5699-000	Wireless LAN PCB	MP560 / MP568 / MP640 / MP990	5 results	$40.58 €46,86

Position numbers and Product codes were copied from the Canon Service Parts PDF. Descriptions are derived from the same source but in ordinary English order. Compatibility is from Web research - it is believed approximately correct and intended to indicate design similarity rather than recommend a spare for individual printers. Check the service parts list for the specific printer. The number of search results is as given by Google in April 2014. Prices in dollars are from executivecolor.net and mk-electronic.de.

Little of interest seems to be going on here. Automatically generated lists are turned into web-site pages but there are two or three actual vendors. Only the Main logic and Wireless LAN board are at all likely to fail but there is no mention of them on forums, they haven't yet made Icecat and they are too expensive to make replacement a likely option.

Ferrite rings serve and important function, they reduce radio frequency emissions from the printer and improve it's immunity from interference. The printer will work without them in most circumstances.

The cables are all Flat Flexible Core (FFC) types. These are a ribbon of plastic with metal strips adhered within. One layer at each end of the plastic coating is cut short so that the metal tracks are visible. Connectors on the circuit boards are spring contacts in a plastic housing to guide and align the plastic ribbon. These cables need careful handling because they will not survive some careless actions.

Main Logic

Almost any fault in the printer might be attributed to the Main Logic: all sensors lead into it and all motors are driven by it. However if the sensor can register and the motor can be driven then the main logic is not likely to be at fault. Faults are much more likely to be cable orientation, damage or seating. Firmware loaded onto the logic could be an issue, but Canon is not likely to issue anything that would cause the printer to frequently malfunction.

Do not download firmware from sites other than Canon, or drivers from sites other than Canon, Microsoft, Apple or you Linux distribution. Any website offering firmware or drivers is most likely to deliver malware.

QM3-6889-000 the main logic for the printer can be ordered through UK distribution but will be priced above £60

Wireless LAN

The QK1-5699 Wireless LAN PCB has resulted in queries to us, and dissapointment. The distributor we used gave a price which comes out around £65, we think they were getting the part from MK and marking up about 25%. We need to review our supplier list from time to time and research like this prompts that.

We are somewhat reluctant to recommend the Wireless LAN PCB as a spare because we think it is far from certain to fix a problem. We think a problem with WiFi is far more likely to be a setup issue than a hardware failure.

As it happens the circuit diagram makes clear that the QK1-5699 is a USB device (most WiFi adapters in printers are) - however firmware in the printer will presumably only support the one chipset. If anyone wants to tell us what the chip says we can look it up.

A bit of research suggests that non of the electronic parts are immediately available in the UK, they are clearly very rarely required. There may be an element of circularity as well because (in 2013) the electronic parts are all sufficiently expensive to suggest a new printer as a better option.

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