# Mainboard Blowing fuses



## ifusion (Jun 3, 2011)

I finally had my t-jet jumbo ii repaired and up and printing. However 48 hours later, I have a blown fuse again on the main board (no printing from the print head, not even on a nozzle check from the lcd control panel of the printer).

Are there any common items that will cause a fuse to blow?


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## abmcdan (Sep 14, 2007)

Ink or fluid getting down the printhead ribbon cables is the main cause I've seen.


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## spiderx1 (Oct 12, 2009)

Ribbon cables, check that the ribbon cable has the, usually, blue spacer tab on the back side opposite the silver connectors. If one of these comes off, very common, it will not seat the ribbon cable correctly causing cross contact and blow fuses. These will be at every connector point on the cables.


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## ifusion (Jun 3, 2011)

spiderx1 said:


> Ribbon cables, check that the ribbon cable has the, usually, blue spacer tab on the back side opposite the silver connectors. If one of these comes off, very common, it will not seat the ribbon cable correctly causing cross contact and blow fuses. These will be at every connector point on the cables.


Thanks for the reply. we had rigged up some rubber seal in the print head container to fix what we assumed to be splash up from the bottom of the print head allowing moisture to get to the print head ribbon cable.

As for the backing of the ribbon cable, what type of material what type of material is that... and can I get a roll of it somewhere? We noted that at least 1 cable didnt have it, but I want to say it was a cable that was at least 6-7 ft long that ran up to the top plate that then relays to the print head cables.

I dont know if that is a cable I can get after market, or directly OEM from epson.. so far I've been lucky enough to get everything I needed either from EPSON or somewhere else, but I haven't seen that cable yet.

Getting this machine back up and going has been a challenge. I felt so close until the fuse blew AGAIN. I had decent quality prints coming out.

Machine died a year ago... let it sit...

Flushed out all the ink in the lines, replaced the main board, replaced the print head, replaced ribon cables.

1)Initially had a few challenges with the mainboard, such as the epson website being down when the tech came out and couldnt download the firmware, 

2)then initially unable to find an epson 7800 serial number to load into firmware utility (because the t-jet didnt have one listed anywhere visibly). 

3) Then the printer had a paper out error... thought it was a bad rear paper sensor... ordered a new sensor and cable, turned out, there was a firmware setting for the rear sensor....

Then a little other print quality issues, but it had finally started to work!!! And now it crapped on me!

Luckily the new parts come with a 90 day warranty.. so I guess its just a little more labor.


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## spiderx1 (Oct 12, 2009)

Long cable probably is not an Epson part. Material can be salvaged from old ribbon cables, glued and trimmed. It needs to be accurate so as to align connectors. The one missing could be causing the issue. For parts you can try Karl Steele at Steeletec.com Or American Screen Supply in Phoenix.


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## ifusion (Jun 3, 2011)

I think my issue may be moisture getting down into the print head. Is there anything that I can use to seal the print head where the cables meet to make sure no moisture gets into it? In particular I saw how this print head was being sold, and it looks like its wrapped in some type of material that may keep it dry?

Mod Series Printhead

Since I have 2 main boards, I went and took a meter to my old board, and its the f8 fuse that burned out. I've been reading other posts on the board and I was wondering if this would be the correct fuse to replace it with, using an external holder.

COOPER BUSSMANN Fuse, Glass, 600 Ma, Pk5 - Fuses - 4CX55|GMA-600-R - Grainger Industrial Supply


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## abmcdan (Sep 14, 2007)

You can use a silicone or gasket maker to goop the cables to prevent moisture getting to the head.


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## equipmentzone (Mar 26, 2008)

ifusion said:


> Since I have 2 main boards, I went and took a meter to my old board, and its the f8 fuse that burned out. I've been reading other posts on the board and I was wondering if this would be the correct fuse to replace it with, using an external holder.
> 
> COOPER BUSSMANN Fuse, Glass, 600 Ma, Pk5 - Fuses - 4CX55|GMA-600-R - Grainger Industrial Supply




You can solder an external fuse holder around the internal fuse on the main board which will then bypass the blown fuse. You can use a 600 ma fuse in the holder.


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