SP-300 not printing CYAN and BLACK ink

[kirkbauguess]

Well, you have a short. Now, let's chase it down. You have to check your ribbon cables. If they a have sharp bend, some of the coating is coming off, rubbing metal or the ends are not seated straight, that could be it. Check the very end of the cable, see if the metal pins are worn out or bent.
Also, you may have blown a transistor on the head board. You can have that check with an ohms meter. Look up mac media. They can repair if for a few hundred if that's it.

 

[allicatgraphics]

that's what i figured it was a short somewhere. All the ribbon cables look good. how can i check the transistor on the main board? I have a ohms meter...thanks!

 

[allicatgraphics]

I keep blowing F3 fuse. I was just told it could be a transistor on the mainboard, a Servo, the print carriage, print cables or the print head. Do anyone know how i can test any of the above to try to determine where the problem is. thanks!