Blowing F3 fuse SP300

[justin_92_92]

Hey guys,
I just sold my Sp300 to a buddy to add to his shop. We printed some stuff at my shop and then loaded the printer up and off to his house. Ive moved it a few times in the past as well. He told me he was getting really bad prints. I went over and saw he was getting something we always called "block printing" where the black and cyan would almost smear from one side to the other. I checked the continuity on the two fuses (f2,f3) and found f3 to be blown. I replaced the fuse and tested it and blew the fuse again. to make it easier ill post below what ive tested.

unplugged the two cables at the main board and turned on - fuse stayed good (eliminate the idea of bad main board that way I read)
Swapped the ribbons at the print heads and blew the other fuse as well (f2 was likely already blown and swapping it blew f3)

Anything else I should be doing to test? could be a bad print head Im guessing but would like to rule everything else out first before I drop the money on the head. That head has a new ribbon cable from head to board so I dont think its that but possible. I checked continuity and the ribbon seems good.

Thanks for any help. This has me stumped.

Justin Robinson

 

[Solventinkjet]

Air dust the terminals on the main board, slider board and print heads. Then just double check each cable lead to make sure it's not damaged or dirty. Those cables tend to fail if you install them more than 2 or 3 times. The leads pop off the plastic.

 

[justin_92_92]

Okay I will do that today. I actually ordered a few back up fuses for all my testing from Solventinkjet last night. Very happy to find them in the US. Im getting good at soldering them in Ill report back.

 

[Jim Hancock]

I would suggest you replace the print head ribbons. Swapping the ribbons and blowing the other fuse pretty much narrows your issue down to those ribbons.

 

[justin_92_92]

I took all the ribbons off (after properly discharging) and blew the connections out with air. I put a new fuse on and tested the fuse after soldering and it was good. I put power to machine but didnt turn it on and then discharged it and tested fuse, Fuse is good. I turned it on using the front panel button and it went through its start up procedure and I shut it off and tested fuse and its blown.

I swapped out print head ribbon cables to be sure when I blew out the connections with air.

(Jim, I think I spoke incorrectly before when I described the "swap out ribbon cables". I meant that I had him unplug from both heads and cross them to the other head. Mind you the f2 was already blown and swapping it blew the f3. So that to me makes it sound like the head is shorting out. Is it possible its a transistor though? Or any way to rule out a transistor before I drop the money on a head? )

the fuses arrived today so I have 5 to play with now

 

[justin_92_92]

another update,
I unhooked both print head short ribbon cables from that head to the board. Left unhooked and plugged it in. I got the too cold warning. I plugged in the left side of the head and started it up. It had some weird stuff pop up on the screen but it ran through the cleaning process and no warnings. I swapped it to the other side of the head and got the too cold warning.
left side of head - bottom board = cleaning on start up, random letters on info screen
right side of head - bottom board = temp too low message
right side of head - bottom board = temp too low
left side of head - bottom board = temp too low
Both removed = temp too low.

I think I have it boiled down to a transistor or a shorted out head. Just not sure how to tell which one it is.

I appreciate all the help.

 

[justin_92_92]

Ill just buy a new head

 

[Jim Hancock]

It seems as if you have a bad head. On the ribbon testing you did, keep the following in mind. Never criss-cross ribbons on the same head, as each side of the head connections have different functions and you can cause mainboard issues by doing that. Also, both ribbons should be plugged in at the same time in order for the system to work correctly. When moving the ribbons from one head to another, move both ribbons. So far, your testing indicates a bad print head.

 

[justin_92_92]

Thanks Jim!
I really appreciate the advise. Any advise on the new head install? Dos and donts?

 

[justin_92_92]

UPDATE!
I ordered the print head from sign-in-china and took about 2 weeks or a little less to get it. I installed it and took great care to make sure I did it correctly. I fired it up and after a second she was printing perfect. I did all the alignments and it is now good to go. I delivered to the new owner and we split the cost of the head. We locked the head before the transfer this time just incase and we also packed the head area with paper towels as I suspect some ink got on the head and burnt it out.

I really appreciate all the help. It made my life a lot less stressful.