Canon Pixma mp250 scanner module pinout? - Page 1
Forum section: electronics / beginners

author: poot36
author_rank: Frequent Contributor
timestamp: September 08, 2014, 05:50:11 am
content: I have a printer scanner combination unit (no fax) and am trying to get just the scanner part of it to work without the printer section connected. I have successfully removed the top scanner portion of the unit and the control board and control panel as well as the power supply. When I connect it all up all I get is errors on the control panel indicators and windows xp refuses to try and use the scanner when I try to control it from the built in scanners and imaging devices icon. Is there any way to use the scanner on its own without the printer? Or is there a way to directly connect to just the scanner section and bypass the normal printer and scanner controler? I know there are two flat flex cables coming out of the scanner section 1 for the scanner motor driver and encoder wheel and 1 that just goes to the scanner bar itself that has the ccd chips and rgb leds on it and some control circuitry for those parts. I do know the youtube user theeprom9 was trying to do a similar thing but make the scanner module into a hand held scanner but had no luck in finding out the pinout of the scanner module.

author: Unknown
author_rank: Unknown
timestamp: September 08, 2014, 09:05:44 am
content: Quote from: poot36 on September 08, 2014, 05:50:11 amLike all the Canon MP-series multifunctions I've seen, the MP250 does the bastard trick of disabling all functions - including the scanner - unless all the ink cartridges are present & usable (or you go through an undocumented process of holding & pressing different buttons at start-up).After I bought a cheap laser printer to replace my MP500 I intended to figure out if all that could be bypassed to use it as a scanner only. In the end it was easier to just dump it on the footpath during the next council cleanup.

author: G7PSK
author_rank: Super Contributor
timestamp: September 08, 2014, 05:32:24 pm
content: Try using Linux I had a cannon printer/scanner and an Epson one both refused to work with windows but the worked fine with linux.

author: poot36
author_rank: Frequent Contributor
timestamp: September 14, 2014, 05:54:35 am
content: Thanks for the advice. I am going to try to use the scanner module on its own. From some research online it has what is called a line scan ccd in it. There are 12 pins coming out of the module and based on how the original driver board is layed out there is GND, power, 3 RGB led wires, clock, analog data out, ccd enable and 4 other wires I have no clue as to what they do. Could I use a Arduino to get some sort of data out of this? Or would I have to use a more powerful micro of some sort?

author: amyk
author_rank: Super Contributor
timestamp: September 14, 2014, 12:39:48 pm
content: There is probably a minimum pixel clock rate, maybe an Arduino would work but you'd have to find a datasheet (or probe it in its original circuit) to be sure.

author: poot36
author_rank: Frequent Contributor
timestamp: September 18, 2014, 05:40:54 am
content: After some more research I have figured out that I have a CIS (contact image sensor) based scanner module not a CCD one. I have not managed to find what the difference is between thes two types except that the optics are different. Would it be like one long CCD or not?

author: poot36
author_rank: Frequent Contributor
timestamp: September 22, 2014, 06:11:40 am
content: Well I have figured out some of the scanner module pin out. Pin 1 5V power (actually 5.3V), 2 Red LED cathode, 3 Green LED cathode, 4 Blue LED cathode, 5 GND, 6,7,8 very thin traces on pcb one of the pins had a fairly quick sine wave on it (did not change when I moved my hand over the scanner module although this could be the frequency of the CFLs in my room) and the other two a slow very low duty cycle square wave that one pin was a dimmer identical trace to the other one (interfearence maybe?), 9 trace almost as thick as power around 1V on multimeter, 10 GND, 11,12 thicker trace then power also around 1V. All these readings were taken with the power on but the scanner not operating due to the current state of the printer not working. Got any idea why the last 3 traces are so thick on the pcb? How would I go about figuring out which pin would enable the scanner module and what clock rate would work assuming that I do not manage to get the printer working enough to get the scanner part of it to work? PS I hate the ink cartridge error that is preventing me from using the scanner on its own. If someone knows how to disable this from the front panel controls or a software/hardware mod I would be great full.

author: poot36
author_rank: Frequent Contributor
timestamp: October 03, 2015, 04:54:39 am
content: Well I now have a component tester and have figured out that pin 1 has a 282 uf cap on it and 260mV with respect to ground on the printer control board with out the scanner module connected. Pin 6 shows two back to back diodes with a voltage reading of 1.41V and 540mV, pin 7 1.76V and 1.08V, pin 8 1.60V and 736mV are confirmed to be i/o pins. Got any ideas why the readings are so different? Pin 9 shows 633mV 195uF. Pin 11 shows 760mV 93.2uF. Pin 12 shows 3.16V 647uF. What power supplies would these last three pins be connected to? The caps around the scanner connector on this board are rated to 10V and there are 4 (2 100uf, 1 220uF, 1 330uF) of them and the rest are rated to 35V and around the power supply input which is 24V. At least they are all Rubycon caps.

author: amyk
author_rank: Super Contributor
timestamp: October 03, 2015, 01:50:51 pm
content: Post some (clear and focused) pictures, we can see things and provide better help that way than trying to understand a textual description.As for the cartridge error, you could figure out how it's detecting that - there's usually a serial EEPROM in the cartridges. It could be anything froma common 24Cxxtoa custom chip/protocol. I'm not familiar with Canon cartridges so can't give much more info on that. A quick searchsuggests it could be 1-wire

author: poot36
author_rank: Frequent Contributor
timestamp: October 04, 2015, 04:15:47 am
content: Here are pictures of the front and back of the main control board. The yellow arrows point to the scanner connector and on the back pin 1 of the connector.