I have recently acquired a second hand "Rocky" III and have been learning up on it.
If you dont have the Mutoh manual goto
http://www.mutoh.be/Mutoh-Europe-Member … .aspx/3445
join for free and get it.
It wont solve your problem but helps !.
I am only slightly initiated in servicing but I do know that holding down the f2,f4 and enter key while pressing power gets us into the service module.
Back to the problem. There are four heads each with two colours in them.
The heads are adjustable this will take you further than normal operator maintenance so beware. The first and last heads have black and yellow in them if you are running 2 x cmyk carts.
Assuming this to be the case then either of these heads could be badly positioned.
If you do a test print nozzle check then the first yellow printed on the right is the head on the right and the second yellow is the head on the left.
black should be out of position as well if its head alignment.
If you have a maintenance agreement dont do this !.
goto head unlock and this will allow you to move the head over to the left where you can look at it.
assuming you work out how to take the head cover off then comparison should help here. one head may not be seated correctly.
there are two screws adjusting each head for position.
This where trial and error takes over unless you can decipher the service mode. dont damage the head or the belt cables please !.
dont leave the head uncapped for more than an hour or so.
hope this gets you some where.