Sp300 and the stupid mistake i made!!

[Turbophein]

i bought a used printer that had heads not printing correctly yesterday.

black and cyan were hardly printing, the megenta and yellow do not print at all.

after setting up the printer and replacing the normal parts, like caps, wipers, dampers, along with a good cleaning, i had the black and blue printing mint! still nothing on the yel and magenta side.

took the manifold off the head, it was completely clogged, fixed that, flushed the head slightly, most nozzles were working when flushing. reinstalled the head and still nothing, i can't even suck ink through the caps. i started thinking it was electrical so this is my dumb moment, being a mechanic i decided to rule some parts out, so i swapped over the cable from the heads, megenta/yel cables on the Black and blue head and vice versa. i was hoping it would fire off the black and blue head but it didn't.

i reinstalled the cables the correct way and now the printer won't print anything. i fear i ruined the head electrically, just not sure.

any advice?

 

[FrankW]

I don't think the heads are ruined electrically, but changing head cables when the machine is powered on or just simply still connected to the power source will kill the head fuses which are soldered on the mainboard.

The fuses are looking like the marked ones on the enclosed pictures (but thats a board of the SP540). Find them, check them with a voltmeter and if they are damaged, replace them with using a soldering iron.

 

[Turbophein]

after doing some research...

this is what i believe happened. the magenta/yel head shorted out and blew a fuse, when i swapped the cables, i believe it popped the other fuse. so i think i have 2 blown fuses and 1 bad head.

i am going to the parts store and i am going to fab up a custom fuse setup, that will make changing fuses a breeze! pics to follow.

hopefully i get the black and cyan head operating again.

 

[Turbophein]

I don't think the heads are ruined electrically, but changing head cables when the machine is powered on or just simply still connected to the power source will kill the head fuses which are soldered on the mainboard.

The fuses are looking like the marked ones on the enclosed pictures (but thats a board of the SP540). Find them, check them with a voltmeter and if they are damaged, replace them with using a soldering iron.

i posted again before seeing this. the machine was unplugged each time i worked on the head. thanks for the help! almost done with my new fuse set up!

 

[FrankW]

i posted again before seeing this. the machine was unplugged each time i worked on the head. thanks for the help! almost done with my new fuse set up!

If you plug in the cable incorrectly, you damage the fuse as soon as you power up the printer. In 99% of the cases, it's not the head.

 

[Turbophein]

If you plug in the cable incorrectly, you damage the fuse as soon as you power up the printer. In 99% of the cases, it's not the head.

thanks, my new fuse setup worked out great! my black and cyan is working great again. i am now going to attempt to plug in the magenta and yel head cables. hopefully that was the problem originally.

 

[Turbophein]

here is the link to my custom fuse holders. hope you like.

http://www.signs101.com/forums/show...p540v-How-to-parts-list&p=1139966#post1139966



also my magenta and yellow are still not working. new head is on its way.

 

[Turbophein]

ok so i have been trying to diagnose the original issue that blew the fuse in the first place. at the moment the f2 fuse the yel/magenta side keeps blowing as soon as i turn on the power on.

i traced it down to the main board by removing the print head cables on the main board. also i can get the yel/mag head to work by using the black/blue head cables which rules out a lot.

from some research i did, some people have had success by testing and changing out the transistors on the main board.

can anyone point me in the right direction for the circuit board schematics?

thanks