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Inkjet Printer electronic fault please help!

jareddoig

Sep 19, 2015
2
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Sep 19, 2015
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Hi,

I am new to this forum and a complete novice to electronics compared to most members - I humbly come to you to find out if my problem is at all repairable.

Device is a Roland Digital printer using waterbased ink with piezo electronic Epson print heads.

problem - one of the 4 print heads had a problem(possible cause waterbased ink spilled on circuit) this normally causes a fuse to blow on a head board which controls power to the heads, there is also a bank of transisitors and special Epson chips Driver IC (E09A19RA) on the head board. the transistors normally get blown if its a big problem with the head which in this case happened. so we replaced the Fuse (MMCT 3.15A), and 1 x Power Transistor (2SA1746 / 2SC4131). This normally sorts the problem out no stress. There is another little transistor looking part which sits very close to the fuse replaced which I think was damaged from replacement the part numner is 2SJ535 I believe its a power regulator...
The head board is directly connected to the mainboard for the machine and the power for the mainboard comes from the head board.
Once we replaced the components we put everything back together and "pop" something went, I could not find what this was but I suspect it had something to do with the power regulator and the mainboard. Anyways the machine would not switch on at all now. Lights came on boards etc but front panel switch didn't work.
We "on" there is a chip on the main board called LatticeM4A3 128/68 which gets extremely hot.

I replaced the mainboard but kept the same head board(not knowing there was still a fault on it) the replacement mainboard powered the machine up but when I went to do something it switched off again. This time I replaced the head board and everything switched on and everything seemed fine until I tried to print. Nothing comes out of the heads - its as if the fuses are blown on head board but everything is fine - as if no signal is being sent to fires the heads or if it is no voltage is being send to do so...again the same lattice chip on new mainboard is getting extremely hot.
I will attached the head theory and the circuit diagrams of the machine. if anyone has any ideas or if the boards are repairable please let me know.
 

Attachments

  • head theory.pdf
    275.6 KB · Views: 264
  • headboard.pdf
    328 KB · Views: 188
  • mainboard2.pdf
    938.5 KB · Views: 194
  • mainboard2a.pdf
    378.9 KB · Views: 171

Martaine2005

May 12, 2015
4,277
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May 12, 2015
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4,277
Hi,
Have you checked the resistance on IC (E09A19RA) pin 18 to ground?
Manual says around 18K ohm is fine but very low 0 or very high Mega to replace it.

Martin
 

jareddoig

Sep 19, 2015
2
Joined
Sep 19, 2015
Messages
2
Hi no I haven't, can this be done with the board out the machine or does it need to be on?

Also I do t think it's this as I tried a different head board. My feeling is that it's the lattice chip. As this seems to control head-power and its all the heads not just one. If it was just one Head I would assume one of those ic on the head board was faulty but all of them would have to be for all the heads not to fire.
 

Martaine2005

May 12, 2015
4,277
Joined
May 12, 2015
Messages
4,277
Yes it seems to be a very complex printer.
I think you need to go back to basics and check the voltages from the power supply. Make sure the regulator is functioning correctly and check all diodes and capacitors in that area.
Perhaps somebody on this forum has experience with this kind of printer may be able to help you.

PS, the headboard.pdf is unreadable. Too small.

Martin
 
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