Hacking the HP45

Powder and inkjet printing
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dragonator
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Re: Hacking the HP45

Post by dragonator »

If you test the printhead, do you get 300/300, or do you get less? If you get 300/300, the nozzles are firing, and it is not addresses you are skipping. HP45 heads clog easily, and cleaning them properly with only water is not enough then. You want isopropylalcohol and a paper towel, and really soak the paper towel and then, without applying too much pressure clean the nozzles.

If you do read less than 300/300, by a significant amount (296/300 is not an issue) then let me know and we can look further.
ghvanhoosesr
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Re: Hacking the HP45

Post by ghvanhoosesr »

Thank you for getting back to me so quickly!

I cleaned the head as advised, and Test Head returns 300/300. The stripe issue still persists.

After cleaning and testing the head I ran a prime cycle, while moving a piece of paper under the printhead by hand. A photo of the results are attached here. What struck me as unusual is the evenness of the spacing with which nozzles are firing and which ones aren't; I verified that the V3 software is sending all the data it should when it should as far as addresses and primitive pins are concerned, so from the software side everything is as it should be.

Also: How might one acquire the V4 hardware? (and how much is it?)
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Re: Hacking the HP45

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That pattern is indeed a bit too perfect. I assume that the nozzles 0-300 go from top to bottom?

What strikes me as weirdest is the fact that you have 7 bars. Each side of the printhead has 7 primitives, so 7 bars is fine, but if you were missing primitives I would assume to see 3-4 bars, not all 7 on each side. I suspect that addresses are missing, but I'd have to look what you need to miss to get a pattern this perfect. As far as I know addresses are more randomly arranged.

V4 hardware is not being sold assembled. Only as kit to be assembled at your own risk. I have decided to scale down HP45 work a bit. A kit with all parts, including 3D prints would be €140 excluding shipping. This includes the currently hard to get Teensy 3.5.
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Re: Hacking the HP45

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Can you show a print? I suspect with the prime the image is over saturated with ink. I want to see if the ink is really there in 7 perfect lines, or if there is a bit more of a mess going on. I suspect that your 4081 chip is either not working, or not connected properly. This would stop the data from going to the printhead after the first 8 addresses, causing the remaining 14 addresses to be skipped. With over saturation this would match the image, though I have a hard time believing that this would be such a perfect split in bars.
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Re: Hacking the HP45

Post by ghvanhoosesr »

Here's a prime I did with a small number of pulses (only about 10 or 20 I think, I don't precisely remember) Again I was holding it by hand so there may have been a small amount of shakiness on my part.
Let me know if you need something more detailed.
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Re: Hacking the HP45

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Given the small number of round dots I see here (only 14), I am fairly certain that all primitives are working, but addresses are not advancing. Either the mosfet level shifter is not working, or the 4081 chip is not working. Do you have the capability to test the addresses on the board?
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Re: Hacking the HP45

Post by ghvanhoosesr »

I do not have any capability to test the addresses on the board.
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Re: Hacking the HP45

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Can you start by sending me a good photo of your setup, driver board and controller board. I suspect I won't be able to see much, but we can at least try.
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Re: Hacking the HP45

Post by ghvanhoosesr »

Actually I think it may have something to do with the pogo pins not connecting properly. Is that a common occurrence? (and if so is there a fix?)
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Re: Hacking the HP45

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The pogo pins not connecting might be a cause, but you'd have to have an issue where a random address IS connected, and the rest isn't while all primitives are properly connected and most grounds are. If there was a random pattern I could believe you had a bad pogo pin connection, but with what seems like all primitives, and only a single address working it seems like something in the hardware is not working. Without the ability to test anything though we won't be sure, and there is only so much I can do from this distance.
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