Headboard transistor question

[bovegas]

Can somebody tell me how to check faulty transistors and tiristors on headboard. i have installed 2 new heads and tried test print and fuse for yellow and magenta tripped but all other colors printed fine. Since yellow was new head I have installed new magenta (3th new head) and replaced fuse for those 2. I tried test print and fuse tripped again but also black and cyan are printing stripes through the whole print. I am asuming there is damage on print head and I am wondering how to check head board. Also why now black and cyan are printing weird when fuse for them is ok. Are they somehow conected with yellow and magenta. Is there posibility that they are fried now. Please help

 

[Gabriel]

If there is any track of ink coming out from the print-head, then it's not the transistor. To check the transistor in a proper way, you would better take out the head board. and measure the two pins from exterior on each transistor. The right value it's between 4.12 - 4.15, I think.
Check out the flat cables!!! Those things are guilty for this printing from edge to edge.
Regards,

 

[Jack Knight1979]

Send it in for a repair to mac media.

Get a new head board for now. If you keep messing with it you'll blow another head.

You will blow your head board again in the future so it's a good idea to keep a spare. I have a spare sitting in cabinet waiting to go in.

 

[Gabriel]

What kind of printer do you have?

 

[bovegas]

I have cj 540. I have instaled new black and yellow head after I have received headboard from macmedia repaired. I did test print and everything was fine except magenta and yelow fuse has blown. I replaced fuse and installed new magenta head. Than I did test print and black and cyan printed through whole print. Yellow and magenta fuse has blown again. I am wondering are black and cyan somehow conected to yellow and magenta. I am afraid black and cyan heads are fried. What do you guys think. I have checked all transistors and tiristors with om meter and they all seems the same

 

[Jack Knight1979]

find out what head channel was transistor went bad in. It could be that magenta is fine. Also, replace the ribbon cables.

 

[bovegas]

How do I find transistor that went bad. When I checked them with om meter they all seem to show same value

 

[Gabriel]

Then it seems that you put a wrong fuse. Or, maybe the fuse blew up again when you turned on the printer. Check it out! This might be caused by a damaged flat cable.