Designjet 500, 800 21:10 Error after belt replacement

Thank you for your wonderful video on Youtube on how to replace the belt. I ordered the belt from LPS and it arrived yesterday and needless to say I spent last night putting it in. With the help from your video I managed to replace it and put the machine back together again. 

However, as soon as I plugged it in, and the machine turned on, the carriageway tried to make a pass over the service station but came to a stop and error message 20:10 came up on the screen. I do know you mentioned in your video that using wrong or longer screw for the fixing the service station to the printer will bring up this error. And I have used the original screws and at no point used wrong screws. I am a bit confused here.

Can you please give me some pointers as to how to get rid of this error.

Thanking you in advance for your kind assistance. 

You indicated you had a 20:10 error and mentioned the service station.  I assume you mean error 21:10.  Please let me know if this is not correct.

The 21:10 error can be caused by anything that inhibits the service station motion.  The best way to troubleshoot the service station is to remove the motor and operate the white gears with your fingers to see if there is any obstruction to the movement of the sled with the 4 print head caps on it.  If there is something inhibiting the motion, that will need to be corrected.

The service station may be in the bracket incorrectly, causing the sled to hit the bottom of the carriage.  You may want to remove the SS and reinsert it.  There is a lip on the front edge of the SS that has to slide on top of a matching lip on the SS bracket.  That could also cause the problem.

The mounting screws for the SS are shorter than the cover screws.  If the cover screws were used to mount the SS, they cause an obstruction for the grey lever on the right side of the SS and the wiper bar will jam.  

The data cable that carries the signals to and from the SS may have failed.  One end is connected to the small interconnect board to the rear of the control panel and the other end is connected to the electronics module.  The 24" cable can be ordered from: /c7770-60267-designjet-500-800-interconnect-ribbon-cable and the 42" cable can be ordered from:  /collections/designjet-500-800-parts-page/products/c7769-60298-designjet-500-800-interconnect-cable 

The grey lever must be able to be moved to the 2 o'clock and 10 o'clock positions and it needs to stay in those positions without falling back to vertical.  If the lever does fall back to vertical, replace the Service Station:

The service station can be ordered from: /collections/designjet-500-800-parts-page/products/c7769-60149-r-designjet-500-800-service-station-74-95-w-exchange

Please let me know if you cannot solve the problem.