Service printhead error 931.01 - Lexmark T650n Laser Printer

You are correct, Below is that section from the manual. Before you follow this, i've found in the past that the cable connector is not seated properly on the rip board, so check this first.
If you require any of the instructions on replacing the printhead or board let me know.


Yellow Printhead Lost Hsync
Check for the correct installation of the all the cables to the RIP
Board assembly and to the Printhead assembly; J2, J3, and J4 on
the RIP Board. Go to "RIP Board" on page 5-11. If the cables are
connected correctly to the RIP Board and to the Printhead
assembly, replace the following FRU:
"RIP Board" on page 4-11 If this does not fix the problem replace:
Yellow Printhead Assembly - Go to "Printheads" on page 4-33.
Note: Whenever a printhead assembly is replaced, it is necessary
to perform the "Printhead Adjustments" on page 4-1.

hi
If this is the firsttime the error has occurred, try turning the printer off. Let it sit turned off for atleast 20 seconds before powering it back on. If powering the printer offand back on clears the error, continue using the printer but watchit to see if any printhead errors return. If your printer continues todisplay a Printhead Error message, make sure it is plugged straight tothe wall and not through a surge device or power strip. Power strips anduninterrupted power supplies can cause a low amperage problem in your printer.This can trigger a printhead error even if the printer has worked on this surgedevice for months.
If theprinter continues to post a 930 Printhead Error, it thinks thewrong printhead unit is installed. If the printer was recentlyserviced, make sure the correct parts were used. This is especially true if theparts replaced were either the printhead unit or the printer's engine/systemboard. It is in one of these two parts that the printer is detecting theproblem. Note: If you are the personrepairing such a printer, please be aware that parts from different,though similar, printer models may not be compatible with this printer.Also make sure to check the laser cable going from the printer's engine boardto the printhead unit, as it reads that signal. If the printer was notrecently serviced before this error occurred and powering the printer off andon does not help, the printhead unit and possibly the laser cable or theengine/system board to this printer may need to be replaced.
If the printer continues topost a 931 Printhead Error, it thinks there is an error in the signalgoing to the laser or the Hsync part of the printhead assembly. If the printer continues topost a 932 Printhead Error, it thinks there is an Hsync error occurringin the printhead assembly. If the printer continues topost a 933 Printhead Error, it thinks there is a failure in either theHsync signal or with the mirror motor unit of the printhead. If the printer continues topost a 934 Printhead Error, it thinks there is a "lock"failure with the mirror motor assembly within the printhead assembly. If the printer continues topost a 935 Printhead Error, it thinks the mirror motor unit within theprinthead unit cannot reach its operating speed.
If powering the printer offand on does not clear any of these errors and it is alreadyconnected directly to the wall, your printer may require service. Itcould have a defective printhead unit or there might be a problem with theengine board or one of the printhead cables. Note:If you are the person repairing such a printer, check all of the cablesgoing from the printer's engine board to the printhead unit for any damage.Also check the continuity across these cables.

f the printer continues to post a 930 Printhead Error, it thinks the wrong printhead unit is installed.

• If the printer was recently serviced, make sure the correct parts were used. This is especially true if the parts replaced were either the printhead unit or the printer's engine/system board. It is in one of these two parts that the printer is detecting the problem. Note: If you are the person repairing such a printer, please be aware that parts from different, though similar, printer models may not be compatible with this printer. Also make sure to check the laser cable going from the printer's engine board to the printhead unit, as it reads that signal.
  
• If the printer was not recently serviced before this error occurred and powering the printer off and on does not help, the printhead unit and possibly the laser cable or the engine/system board to this printer may need to be replaced.

Hello my friend,this is printhead error,check connections at both ends of cable for corosion or oxidation,reconnect them.Also can be system board error.You can check the operation of
the printhead shutter and clean the printhead window with a lint-freecloth folded over a cotton swab; do not use a bare swab and do not use any cleaning fluids or water on the printhead window if you see the defect on the photo conductor.Good luck:)

Error Condition Indicator Beeps Error
Code Possible Solution Paper Feed / Delivery Orange 2 Remove any paper jammed Paper Jam Orange 3 Remove any paper jammed Ink Out Orange 4 Add Ink BJ Cartridge Misinstalled Orange 5 Re-install cartridge or replace it NO BJ Cartridge Orange 6 Re-install cartridge or replace it BJ Cartridge Error Orange 7 Re-install cartridge or replace it Waste Full warning Orange 8 Waste is almost full , needs service very soon Service Errors Blinks Beeps Error
Code Possible Solution ROM Error 1 x Orange 10 6100 Try unplugging Printer RAM Error 2 x Orange 10 6300 Try unplugging Printer EEPROM 3 x Orange 10 6800 Try unplugging Printer Home Position 4 x Orange 10 5100 Temperature Sensor 5 x Orange 10 5400 Try unplugging Printer Waste Full 6 x Orange 10 5B00 Needs Service Cartridge OverHeat 7 x Orange 10 5200 Replace the BJ Cartridge(Printhead) Cartridge OverHeat 8 x Orange 10 5200 Replace the BJ Cartridge(Printhead) Cartridge Displaced 9 x Orange 10 5200 Replace the BJ Cartridge(Printhead) or reinstall Cartridge Displaced 10 x Orange 10 5200 Replace the BJ Cartridge(Printhead) or reinstall Cartridge Displaced 11 x Orange 10 5200 Replace the BJ Cartridge(Printhead) or reinstall Other Hardware error 12 x Orange 10 6500 Other Hardware error None None 5910 Needs Service Other Hardware error None None 5C00 Needs Service

a 935 printhead error is a fatal error which means the scanner motor has failed to initialize. the term printhead is short for printhead scanner. this error can be caused by either the engine board or the scanner % wise 40%engine board 60% scanner ive done 120 repairs on lexmark laser for the last 7 years trust me one of these is the problem

there is a Printhead error - No first sync

To resolve the error condition:

1. Open the printer access door.
2. Remove the color and black ink cartridges.
3. Remove, then reinstall the printhead

To reinstall printhead follow the link.
http://www.kodak.com/global/plugins/acrobat/en/service/manuals/AiOPrinters/printhead/AUR1780-9_UE_RevC.pdf

93x Printhead Error
Each printhead error has its own error code number. The error codes and their respective meanings are listed below, together with some actions you can take to resolve the problem. 


ALL printhead errors:
If this is the first time the error has occurred, try turning the printer off and on. 
Let it sit turned off for at least 20 seconds before powering it back on. 
If powering off and on the printer clears the error, please continue using the printer but watch it to see if any printhead errors return. 
If your printer continues to display a Printhead Error message, make sure it is plugged straight to the wall and not through a surge device or power strip. Power strips and uninterrupted power supplies can cause a low amperage problem in your printer. This can trigger a printhead error even if the printer has worked on this surge device for months. 
  
If the printer continues to post a 930 Printhead Error, it thinks the wrong printhead unit is installed. 
  
If the printer was recently serviced, make sure the correct parts were used. This is especially true if the parts replaced were either the printhead unit or the printer's engine/system board. It is in one of these two parts that the printer is detecting the problem. Note: If you are the person repairing such a printer, please be aware that parts from different, though similar, printer models may not be compatible with this printer. Also make sure to check the laser cable going from the printer's engine board to the printhead unit, as it reads that signal. 
If the printer was not recently serviced before this error occurred and powering the printer off and on does not help, the printhead unit and possibly the laser cable or the engine/system board to this printer may need to be replaced. 
 
If the printer continues to post a 931 Printhead Error, it thinks there is an error in the signal going to the laser or the Hsync part of the printhead assembly. 
If the printer continues to post a 932 Printhead Error, it thinks there is an Hsync error occurring in the printhead assembly. 
If the printer continues to post a 933 Printhead Error, it thinks there is a failure in either the Hsync signal or with the mirror motor unit of the printhead.  
If the printer continues to post a 934 Printhead Error, it thinks there is a "lock" failure with the mirror motor assembly within the printhead assembly. 
If the printer continues to post a 935 Printhead Error, it thinks the mirror motor unit within the printhead unit cannot reach its operating speed.
 
If powering the printer off and on does not clear any of these errors and it is already connected directly to the wall, your printer may require service. It could have a defective printhead unit or there might be a problem with the engine board or one of the printhead cables. Note: If you are the person repairing such a printer, check all of the cables going from the printer's engine board to the printhead unit for any damage. Also check the continuity across these cables. 


Source: Lexmark KnowledgeBase

Basically this is a Lexmark printer.

Try these if no result replace printhead ( can be expensive will try to find the comparable to the lexmark.

93x Printhead Error

Each printhead error has its own error code number. The error codes and their respective meanings are listed below, together with some actions you can take to resolve the problem.

ALL printhead errors:

1. If this is the first time the error has occurred, try turning the printer off and on.
2. Let it sit turned off for at least 20 seconds before powering it back on.
3. If powering off and on the printer clears the error, please continue using the printer but watch it to see if any printhead errors return.
4. If your printer continues to display a Printhead Error message, make sure it is plugged straight to the wall and not through a surge device or power strip. Power strips and uninterrupted power supplies can cause a low amperage problem in your printer. This can trigger a printhead error even if the printer has worked on this surge device for months.
   
   • If the printer continues to post a 930 Printhead Error, it thinks the wrong printhead unit is installed.
     
     • If the printer was recently serviced, make sure the correct parts were used. This is especially true if the parts replaced were either the printhead unit or the printer's engine/system board. It is in one of these two parts that the printer is detecting the problem. Note: If you are the person repairing such a printer, please be aware that parts from different, though similar, printer models may not be compatible with this printer. Also make sure to check the laser cable going from the printer's engine board to the printhead unit, as it reads that signal.
     • If the printer was not recently serviced before this error occurred and powering the printer off and on does not help, the printhead unit and possibly the laser cable or the engine/system board to this printer may need to be replaced.
       
   • If the printer continues to post a 931 Printhead Error, it thinks there is an error in the signal going to the laser or the Hsync part of the printhead assembly.
   • If the printer continues to post a 932 Printhead Error, it thinks there is an Hsync error occurring in the printhead assembly.
   • If the printer continues to post a 933 Printhead Error, it thinks there is a failure in either the Hsync signal or with the mirror motor unit of the printhead.
   • If the printer continues to post a 934 Printhead Error, it thinks there is a "lock" failure with the mirror motor assembly within the printhead assembly.
   • If the printer continues to post a 935 Printhead Error, it thinks the mirror motor unit within the printhead unit cannot reach its operating speed.
     
5. If powering the printer off and on does not clear any of these errors and it is already connected directly to the wall, your printer may require service. It could have a defective printhead unit or there might be a problem with the engine board or one of the printhead cables. Note: If you are the person repairing such a printer, check all of the cables going from the printer's engine board to the printhead unit for any damage. Also check the continuity across these cables.