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Author Topic: Epson 7900 from the inside - out  (Read 1092473 times)

Blue moon

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Re: Epson 7900 from the inside - out
« Reply #1280 on: February 17, 2013, 10:11:31 am »

Photoflo is extremely gentle (as are virtually all non-ionic detergents).  Photoflo contains between 5-10% detergent according to the MSDS and is also 25% or so propylene glycol so you need to figure that in as well in terms of what you mixture is.  For normal film work (eliminating water spots from processed negatives) the dilution is 1:200 but that's going to be way too weak for what we are looking at here.  I suspect that you can begin with a 5% amount of photoflo and see if that works (this would give you a final detergent concentration of 0.25% which is similar to what one gets when washing dishes!).  Having never seen a head in real life, I wonder if they are immersible in a cleaning solution without doing any damage.  This way one could use a warming bath to improve the cleaning process (much the same way as warm/hot water helps remove crud from dishes without scrubbing).  Eric might have a better feeling for this.
Alan
Much appreciated....will stop to think before i jump in
Matt
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Blue moon

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Re: Epson 7900 from the inside - out
« Reply #1281 on: February 17, 2013, 06:59:37 pm »

Yes I agree on the reverse flow and sucking fluid from the face of the head as well. My only worry is when doing so you have to make certain small particles like lint or debris from the air that can land in the container of liquid cleaner your using aren't pulled into the front nozzle's along with the fluid cause then your going to get some more clogging. I also thought you could always take an old capping station apart and make a small desktop cleaning station for the head that could seal up against it while your cleaning as well as you could pull liquid thru the capping station head via the black tube that runs to the pump for that shared channel as you use a syringe on the nipple side of the head and put a rubber plug over the other shared nipple to stop it from pulling air. Not sure if that makes sense but I see it in my mind. Maybe I can draw something up later but im trying to think of ways to minimize creating clogs and treating it as if its in a clean as possible environments so as to not create more issues and have a controlled test.
Higgy
How are you getting on with your new desktop cleaning invention......would make a very clean safe environment to pull solution backwards through the head.....how would the reinvented capping station get its supply of solution to suck into the station ?
Thanks
Matt
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Blue moon

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Re: Epson 7900 from the inside - out
« Reply #1282 on: February 17, 2013, 07:17:32 pm »

Hi All

As Epson are so good at making nozzles many in their next series of printers they could have a separate set to spray cleaner at the print head as it or before it docks or when the wiper blade cycles.

Just a thought it could be 2 channel and spray the red and then neutralise it with clear.?


Jon

btw epson you heard it hear first
Yes as the head returns to the parking station a simple spray gun squirts ...........
  the wiper blade and bottom of the head simultaneously......
You are then told to replenish your little solution reservoir when the solution level in the tank drops below a minimum level.....sounds just like what we do every day to deal with dirty windscreens in our cars.....
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Blue moon

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Re: Epson 7900 from the inside - out
« Reply #1283 on: February 17, 2013, 07:22:19 pm »

Ok, so here's where I am with my 9890.

I had a clog in the Y channel, with about 30% of the nozzles clogged. Tried cleaning, power cleaning, SS cleaning and nothing changed.

Called Scott at American Inkjet Systems (who has been very helpful) and got some of his cleaning fluids. Tried spraying the capping station per Scott's suggestion with CPL 007+, no changes. Then Scott suggested soaking a paper towel in CPL 007 and parking the head over it for at least 5 hours. This, I feel was a mistake. The head sucked up some fluid and I think it broke some of the clogs free which when I did a cleaning proceeded to ram themselves into a bunch of new previously unclogged nozzles. I now have 8 clear nozzles on my Y channel. Every other colour is perfect.

Scott is sending me some cleaning carts but I think the odds of anything happening with this clog is slim to none. If I were to try and fix this again I would first run the cleaning carts and then try the paper towel trick hoping that whatever clogs are dislodged from the nozzles would be broken down by the cleaning fluid the head is loaded with. As is stands, I don't think there's enough free nozzles to ever be able to clear the head and lines of the ink and fill the head with cleaner.

At the risk that you have replied later.....did you get your cleaning solution....did you get success ?
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Blue moon

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Re: Epson 7900 from the inside - out
« Reply #1284 on: February 17, 2013, 08:52:29 pm »

Chaddro,
All these places that sell these cleaning "solutions" always have a disclaimer that the product will not be effective if you have burned out the head. Even Ericks guy "Oh Canada" had this disclaimer on his site.
I may be wrong but I believe that most people that have serious "clogs" and have done multiple power cleans have already done too much damage to their head, and cleaning is no longer an option. It all boils down to just how much repetative, consecutive cleaning, will do damage to the head.
 
I hope I'm wrong...
David

David
Even if you were wrong you are still right in so many important ways....i print rarely but i am constantly reminded to power clean on the 7800 ...i have been told that the printer is programmed to remind us to do power clean even though i know that the printer is spotless....there is a program running behind the scenes that is looking at
 average not exceptional situations...this program is guessing when i need a power clean and i am quite happy that it has no real idea of the condition of the head day to day....you are all aware that i have spent the last year passing through nearly perfect auto clean tests month after month.....guessing here but i was probably reminded
A dozen times during the year to power clean....bizarre
So ....totally separate to Erics breakthrough (hopefully ) I know you will agree with me that the whole area of power cleaning and its associated risks and procedures will need to be carefully spelt out to all of us....we need education on power cleaning no matter how successfully and separately we crack the clogs issue...
One thing confuses me on the 900 and the power dilemma......we know that the 900 does not charge the piezos when it power cleans ( except in SS mode )......so if piezos are dormant when fluid is sucked out of the head where i wonder could the damage to piezo unit actually come from ?
Matt
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Eric Gulbransen

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Re: Epson 7900 from the inside - out
« Reply #1285 on: February 18, 2013, 11:45:01 am »

I have something interesting to share.  Potentially critical to 9900/11880 users.  I got a call from Edward the juggler at work Friday.  He's got an 11880 now.  He's been printing fine since spending $3,000 on a D1 new head install.  But suddenly, after doing a few 60"X90" prints, his drive band snapped.  Not sure of the proper name yet, but it's the steel band that drives the carriage left to right as the machine prints.  He asked if I had heard of this happening before.  I told him no, but that I knew why it broke.  I've taken three 7900s apart by now, and one 9900.  The head (carriage holding the head and damper unit), once released, slides effortlessly on the rails on the 7900s.  This is not the case on the 9900 that I took apart though.  I will look into why but for now my suspicion is most prints we run on the wider machines are not always wider prints, so the rails don't get lubed as often - way out on the run.  Like maybe in the 30 to 60" range.  I don't know what type of lube the rails get, yet, but I will.  Perhaps this lube dries out.  I can tell you definitely there is a huge difference in the resistance that I feel sliding released heads on the two different machines.  This 9900 even gave out a very quiet squeak or two first time I drove the head through it's full range of movement.  This added resistance is easily the reason for Edward's band breaking.  

So the warning here is release your head and slide it through it's range.  If it feels like butter you're alright.  If it doesn't, you need some lube.  Exactly what lube, and how much, is something we need to find out.

I talked Edward through disassembling the right side of his machine so that he could manually cap his new $3,000 head.  With access to the rear of the pump and cap assembly it is possible to manually roll the cap's drive gear until it draws up to the head.  This process gave him a good look at the band, and what it will take to replace it.  He is confident that he can do it on his own.  We'll see if Epson will sell him the part.  

We now have two things to keep from drying out on these machines.
« Last Edit: February 18, 2013, 11:47:10 am by Eric Gulbransen »
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Blue moon

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Re: Epson 7900 from the inside - out
« Reply #1286 on: February 18, 2013, 12:18:02 pm »

I'm really glad you guys like the video.  Thought about it all day doing the framing hammer thing.  It's not perfect of course, already I see that I left out the part about unplugging the machine after power-down. 
Eric
A bit of advice please if you would...
After power-down and plugs pulled out of the wall.......i seem to recall you being advised by another expert to watch out for capacitator risks even after power-down.....i think the advice was to press down the ON button after power-down and cables disconnected to release any static electricity left in the capacitator.....what do you think..
Thanks in anticipation
Matt
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davidh202

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Re: Epson 7900 from the inside - out
« Reply #1287 on: February 18, 2013, 12:38:15 pm »

 The need for capacitor discharge applies to just about any electronic device before attempting service , some more than others dependant upon the size and actual storage charge of the capacitor (farad rating). Flash capacitors which store a lot of energy or are used in power supplies, are especially nasty if you don't discharge before completing the circuit with your fingers :o.

most circuit boards with small capacitors won't do any harm.

Static electricity on the other hand can fry some chips so that is more of a worry.
Always discharge your body by grounding before attempting any work on or near the circuit boards ;)

David
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Blue moon

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Re: Epson 7900 from the inside - out
« Reply #1288 on: February 18, 2013, 01:54:15 pm »

I completed my first fifteen day auto test last week......without any printer "rocking " of any description......just turn on printer daily....no printing.......result was completely successfull auto test on the first try after a lapse of 15 days since the previous auto test...so far no advantage for rocking ....
Printer starting up beautifully...16 degrees Celsius 53 humidity.......rather a cold room but the inks seems to like it....dark room facing north...never any direct sunlight.......
Be back after stage two which is now well under way......
Hi Everyone
just finished second 15 day auto test today..no printer rocking , no printing......k3 inks.....daily start up....7800...
16 celsius 56 humidity.....cold dry room....
Absolutely perfect auto test.....first go....and each days start up was sweet.....knew there would be a good test...
Could be eating my words about rocking....
What a beautiful printer Mr Epson.......
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Blue moon

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Re: Epson 7900 from the inside - out
« Reply #1289 on: February 18, 2013, 01:56:48 pm »

The need for capacitor discharge applies to just about any electronic device before attempting service , some more than others dependant upon the size and actual storage charge of the capacitor (farad rating). Flash capacitors which store a lot of energy or are used in power supplies, are especially nasty if you don't discharge before completing the circuit with your fingers :o.

most circuit boards with small capacitors won't do any harm.

Static electricity on the other hand can fry some chips so that is more of a worry.
Always discharge your body by grounding before attempting any work on or near the circuit boards ;)

David
David
Thanks
Matt
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Eric Gulbransen

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Re: Epson 7900 from the inside - out
« Reply #1290 on: February 18, 2013, 06:55:13 pm »

This is exactly the type of stuff we need - community efforts.  I can't do this alone, and get it all right.  Thank you for this and any other tips, suggestions, changes, whatever.  I will make the changes.  But what exactly please.  How do we purge the machine of any charge?  Hitting the power button after un-plug, does that really do it?  What's the best way to ground yourself to rid yourself of static electricity?  Does rubbing a balloon on your head do it?  Dragging your shoes on the carpet?  I want to get this right..   

The need for capacitor discharge applies to just about any electronic device before attempting service , some more than others dependant upon the size and actual storage charge of the capacitor (farad rating). Flash capacitors which store a lot of energy or are used in power supplies, are especially nasty if you don't discharge before completing the circuit with your fingers :o.

most circuit boards with small capacitors won't do any harm.

Static electricity on the other hand can fry some chips so that is more of a worry.
Always discharge your body by grounding before attempting any work on or near the circuit boards ;)

David

plui

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Re: Epson 7900 from the inside - out
« Reply #1291 on: February 18, 2013, 07:18:20 pm »

I have something interesting to share.  Potentially critical to 9900/11880 users. ...

Thanks for this Eric, I'm using an 11880 as well, and even though this thread details 7900/x900, series I found the info here very helpful, especially the videos -- great for understanding the general process of assembly/disassembly, capping station, wiperblade change of the 11880 as well.   
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davidh202

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Re: Epson 7900 from the inside - out
« Reply #1292 on: February 18, 2013, 08:41:40 pm »

Erik,
Dragging you shoes on a carpet, stroking your favorite furry friend ( I won't even go there ::)), or rubbing your hair with a balloon, is exactly  what not to do. This builds a charge, (especially in cold dry weather). You essentially become a capacitor storing the static energy, and waiting for a discharge .
You may or may not actually have a charge built up and it wont hurt you in any way most of the time but it pays to play it safe around circuit boards with components that may be sensative to static and be fried in the process.

The best conductor to discharge yourself on is a METAL cold water pipe, as they usually go directly into the ground at some point.
Most electrical circuit board panels anywhere, have a heavy copper  (wire or braided) that is clamped directly  to a cold water line or a metal stake directly into the ground which becomes the ground conductor.That would also be a good choice. Once done don't do any of the above or you will once again build up a charge.
Eric, ask one of your electricians on a job site to show you one.

As far as whether or not the printers discharge when powered down as Matt said ,I have no idea.
As long as you don't touch any of the circuit boards terminals (solder joints), there should be no problems.

David
« Last Edit: February 18, 2013, 08:44:57 pm by davidh202 »
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Eric Gulbransen

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Re: Epson 7900 from the inside - out
« Reply #1293 on: February 18, 2013, 09:04:46 pm »

Although barely humor, and definitely twisted, you of all people davidh202 must know the balloon was a joke.  I mean I'm dumb, but I aint stupid. 

...wait a minute.

I like the cold water pipe over the earthing electrode.  I can see people tripping over old wheelbarrows walking down forgotten alleyways looking for their grounding rod.

Thanks david!

davidh202

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Re: Epson 7900 from the inside - out
« Reply #1294 on: February 18, 2013, 09:19:00 pm »

 
"Although barely humor, and definitely twisted, you of all people davidh202 must know the balloon was a joke".
I knew that ;)

  "I mean I'm dumb, but I aint stupid".
your very far from either  !!

 
  
 
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Eric Gulbransen

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Re: Epson 7900 from the inside - out
« Reply #1295 on: February 19, 2013, 02:10:11 am »

"More to come"     ....came tonight. 

and with it it brought new news

...and new rules.

I just took the framing-hammer fatal error head out, and apart.  It's all together mostly, minus a few fatal things here or there.  First of all my hopeful suspicions were correct, I did clear it, and it did print.  But my fears were correct too, I did damage it as well. 

All along, since printing my test page with it, I've held a sneaky suspicion that while it did print 75% of a page before it blew up - it did after all blow up.  Initially I felt it ran out of ink, then overheated.  But ever since then I've been asking myself, "Why in the hell did it run out of ink?  I primed it after all...  something must be wrong."

The autopsy results are now in, so speculation is over - it did run out of ink.  But you'd never guess why.  and I mean you would never, guess, why. 

First of all tonight's autopsy positively confirms my ink-flow theory.  Ink DOES indeed flow over the speed bumps on it's way to the nozzle openings, just like I drew it.  So if that chamber is clogged solid with dried ink, your nozzle is shut down.  Period. 

Second of all tonight's autopsy confirms my next fear - Ultrasonic cleaning is OUT.  You'll learn why in a minute, for now though suffice to say it's too much vibrating for these teeny chamber walls to endure.

Third of all tonight's autopsy confirms a new challenge, at least for me.  Forcing fluid through the head, even gently, is also OUT.


Now on to what I saw:


The following damage illustrates the result of too much pressure applied while forcing cleaner through the head.  The chamber deck floor is blown out.  This missing floor gives a clear view of the enclosed reservoir that runs under the chamber deck.  The broken piece of chamber deck laying on top of the chamber walls also gives a clear view of the electrics running across the bottom of it.  This proves electric charge makes direct individual contact with each and every chamber wall, all along it's length.  I can only speculate at this point but charging a chamber wall at just one end mostly likely wouldn't make it flex throughout it's entire length, which I suspect chamber walls do.  Electrics running the full length of each wall supports my suspicion that the entire wall flexes, which creates positive pressure, which fires the "nozzle".




This next image illustrates what I suspect is the result of ultrasonic cleaning.  Perhaps the vibration is just too much for the ends of the chamber walls - which extend out from the speedbump and into the main ink reservoir.  It's either the pressure of the thick ink vibrating the wall to death, or the wall vibrating itself to death in the thick ink.  Either way death is the result.




The third image, here, is most fascinating to me.  Also exciting.  Look at those short black lines lodged between some of the chamber walls.  Those are more than black lines, they are the broken ends of the chamber walls. To me this confirms my theory that the ink flows from the main reservoir, over the speed bumps, and to the nozzle opening - because these chamber wall ends obviously got sucked in there as they followed the flow of ink.  Sure, this is exciting, I guess.  But this is not what I find fascinating.  What I find fascinating is the fact that this is the green chamber, of the 9900 head with the entire green channel missing in nozzle patterns.  Why am I so excited you ask?  Because if the chamber wall ends got sucked into the chambers, GREEN INK WAS INDEED FLOWING (even though it was cyan in this test..)

Ladies and gentlemen, we (almost) cleared an un-clearable head.




This last image does not confirm any theories, instead it solves a mystery.  Tonight I learned what the extra chamber walls which are not related to any nozzle openings, do.  I also learned what the zig zag walls are on the OTHER side of the nozzle openings.  I now think these secondary chamber walls are essentially pumps.  I suspect they pump ink (or in this case "coolant") through the back side of the nozzle end of the chambers.  The more I study the images, and illustrations that I have made, the more this new cooling theory makes sense. 



Blue moon

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Re: Epson 7900 from the inside - out
« Reply #1296 on: February 19, 2013, 07:35:18 am »

Erik,

As far as whether or not the printers discharge when powered down as Matt said ,I have no idea.
As long as you don't touch any of the circuit boards terminals (solder joints), there should be no problems.

David
Eric and David
I have no idea about discharging the capacitator or the printer on shut down by pressing down on the ON switch after the current has been turned off at the wall socket..it was HIGGY who brought all this up about frying stuff.....
You guys in the States are on 110 volts ...right?  In europe we are on 220 volts ....so we might need to be more careful !
What i have also picked up about static in our bodies ( as well as what David told me in his last post ) is
1 turn off the On switch on the wall plug first.....leave the plug in the wall socket.....just make sure there is no current coming out of the wall....the fact that the cable is still plugged into the socket on a completely dead plug allows you just to touch that dead wire on the outer plastic and this will give you the facility to ground yourself on to the earth wire that seemingly is still an earth even though there is no current coming through that cable....sounds weird....
2 turn off the printer ON switch next
3.pull out the live wires plugged into circuit boards.....just in case
4 cold taps sounds super....also touch yourself off the main steel frame of the printer often....and tools too....rub them off the steel frame of the printer....everybody and everything has to have the same voltage running through themselves....no variations in voltage
5 timber floor good
6 humidity ( i have no idea ) between 40 % and 60% ....static does not like high or low humidity..
I am an amateur electrician since i was 9....not to be trusted...........
Hey Eric...
You know your brilliant idea for magnetising a long stem screwdriver by rubbing it on a broken speaker magnet...i just wonder would static like that particular friction  going on....David might tell us if he would recommend making sure that you ground the magnetised screwdriver on say a cold water tap next.....or use an ordinary screwdriver when you have to poke about possible static places....just a bad thought !
Btw...i bought a beautiful tiny circular magnet with a hole in the center that slides the magnet right down the shaft of a posi 1 sized long stem screwdriver.....as you get down into the bowels of the printer....just slide the magnet down the shaft to catch the screw before it falls off....the magnet unit also have a circular plate that completely neutralises the magnetic field if you just want to focus on one screw but nothing else.....you probably have a great range of those magnets where you live.......just thought i would mention it....also it wont work if the space is too narrow ...back to the magnetised screwdriver on its own....
Thanks
Matt
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Blue moon

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Re: Epson 7900 from the inside - out
« Reply #1297 on: February 19, 2013, 09:56:47 am »

Eric
You never surprise me...
Look at the amount of knowledge you gained from twisted metal....that what started out being a twisted piece of metal and a fed up Eric in actual fact turned out telling you about ink flows..in ways that would never be indicative or conclusive from smooth head operation alone...you now know why things work and dont work for the first time......
You are learning more from the rough than the smooth..
.... You will probably end up being a forensic scientist in no time...

Are you completely against pulling ink backwards through the head or is it just pushing ink forward thats a no go...need to know before i photoflo into the unknown.......i am definitely going to drip feed with an elephant syringe....but will i power syringe backwards after the drip session....what do you think ?
Thanks
Matt
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davidh202

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Re: Epson 7900 from the inside - out
« Reply #1298 on: February 19, 2013, 10:34:44 am »

Eric,
  I have a question on that first image of the chamber and pieces.
It appears that the ends of the channels are balled up. is that just balls of ink at the broken edges, or is it what I am thinking as actually melted metal, same as the ends of a light bulb filament when it blows out due to burning not breaking?

If it those edges are melted, then they were fried before you did the ultrasonic, and the ultrasonic simply broke the already damaged parts apart and left scattered pieces within the chambers!
David
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Eric Gulbransen

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Re: Epson 7900 from the inside - out
« Reply #1299 on: February 19, 2013, 11:31:31 am »

davidh202, I combed over the images again this morning - looking specifically for balled over chamber wall ends.  I find only hard edges, either of the original ends which are tapered actually, or of the broken edges.  I actually have yet to find visible evidence of anything melting in these piezoboards.

Blue moon
, the only sucking that goes on in these machines comes from the pump and cap assembly.  It builds negative pressure once sealed against the face of the head, then sucks ink through the face of the head in the direction that ink flows during printing.  I see warning signs surrounding the idea of creating negative pressure "artificially" against the face of these heads, and sucking ink (or cleaner) out manually.  One of the most sensitive parts of these heads is the bond between the printhead face and the top of the piezoboard.  I don't plan on jeopardizing that.  I've done enough jeopardizing...

thanks for the props guys, it helps maintain motivation.
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