Pixma ip7250 strange error after replacement of print head and mother board

[AndrewF]

I have replaced both motherboard and print head of a totally dead printer, placing also new cartridges before power on, but happened this:
printer powered on but power led and resume led flashed alternatively, the printer is not recognized.

I have tried to to hold down power button pressing 5 times resume button because I have heard this enter in service mode and could be helpful, now the printer power on, moves head on the left then power off.

 

[Hogwild]

It sounds to me like the "new" print head or motherboard may be bad. A quick Google found these:

Canon Pixma iP7250 has died. Checked troubleshooting part of​

https://www.justanswer.co.uk/printe...ip7250-died-checked-troubleshooting-part.html

Canon ip7250 Print Head Error​

https://www.printerknowledge.com/threads/canon-ip7250-print-head-error.14490/

When a Canon print head fails it can but does not always damage the logic board in the printer. A logic board damaged by a defective printhead can but does not always damage a new printhead. So swapping printheads between printers for troubleshooting is risky.

This article is not directly related, but may give helpful background info:
Canon Pixma IP7250 - Error 1403: Printhead Temperature Sensor Error, Reset or Bypass Solutions
https://www.elektroda.com/rtvforum/topic3118958.html

 

[The Hat]

I have replaced both motherboard and print head of a totally dead printer, placing also new cartridges before power on

The first question I’d ask, where did you buy the mother board and print head, was it through Canon or on EBay ?

 

[AndrewF]

It sounds to me like the "new" print head or motherboard may be bad. A quick Google found these:

Canon Pixma iP7250 has died. Checked troubleshooting part of​

https://www.justanswer.co.uk/printe...ip7250-died-checked-troubleshooting-part.html

Canon ip7250 Print Head Error​

https://www.printerknowledge.com/threads/canon-ip7250-print-head-error.14490/








This article is not directly related, but may give helpful background info:
Canon Pixma IP7250 - Error 1403: Printhead Temperature Sensor Error, Reset or Bypass Solutions
https://www.elektroda.com/rtvforum/topic3118958.html

I was aware of the dreadful design that may cause bad print head to damage motherboard and bad motherboard to damage print head so I have replaced both at same time.

Any suggestion on how to check that printhead is faulty so that I can exclude the error is caused by motherboard?

I haven't any certainly working motherboard or certainly working print head and thanks to the criminally bad Canon idea to make the damage of a printhead to damage motherboard and viceversa I haven't much room for attempts that don't imply damage of good components.

I have a multimeter but no technical details about print head to do a test.