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[Résolu] Mk4 screen goes blank after some time  

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gabriel
(@gabriel-4)
Active Member
RE: Mk4 screen goes blank after some time

Hey there,

Thanks for sharing.

As I said above, my MK4 is currently on RMA. I asked why some people get a replacement and some have theirs repaired. The head of the service dept got back (very quickly, which was appreciated) to me saying that they are now confident about having thoroughly diagnosed and identified the (LCD) problem. They have also determined the best solution to address this problem going forward. He did not share any of the technical details about either of the problem or the solution.

So my guess is that they now have established a repair pipeline for this issue and that's why they are not sending back new printers (which presumably would have the same fault).

Just thought I would provide this update for you all.

Regards,
gabriel

Publié : 14/07/2023 9:44 am
FAB1150
(@fab1150)
Active Member
RE:

 

Posted by: @antimix
 
However, It would be interesting to have an oscilloscope on the LCD side power pins and capture the power data during the setup phase, to see if as example there are voltage drop, or spurious signals on the DC power. May be the DC just drops below 4.6V and the LCD logic hangs.

For now I will wait, hoping not to do all the troubleshooting on my kit.

I'd be quite interested too! Unfortunately I don't own an oscilloscope (yet). Who knows, maybe this will be the thing that finally makes me get one :p

Ce message a été modifié il y a 1 year par FAB1150
Publié : 14/07/2023 10:19 am
Microtic
(@microtic)
Active Member
RE:

So they've updated the xLCD boards as per the build instructions. The PE cable has been completely relocated to the other corner of the board!

https://help.prusa3d.com/guide/6-xlcd-assembly_437030

They say,

There is no functional difference between the xLCD boards. The only difference is the position of the PE mounting point and compatible printed parts.

But I wonder if this change is to try and mitigate this issue.

I'm about to build my printer this weekend. I really hope I don't have the problem. 😥 

Ce message a été modifié il y a 1 year par Microtic
Publié : 14/07/2023 1:27 pm
Antimix
(@antimix)
Reputable Member
RE: Mk4 screen goes blank after some time

I would have replaced the flat ribbon cable with a LAN CAT-7 Cable, since twisted pair are more resistant on signal noise.

Probably it would have required to solder the cables on the pins of a female ribbon cable not for crimping.

In the meantime I  have seen that my MK4 Kit has been delayed of two weeks on the original schedule. I hope it will arrive with the issue solved. Cross fingers.

Best Regards

 

Publié : 15/07/2023 7:09 pm
lfachaux et FAB1150 ont aimé
Philipp
(@philipp-8)
Eminent Member
RE: Mk4 screen goes blank after some time

I received my printer a few days ago (a kit) with the newer screen layout, I have got the error as well. I am running the latest alpha also. In a 2-hour print it happened close to the end, it did finish though, then it didn't happen for a few short prints, then it happened again in the middle of a print but the screen came back. All the cables are plugged in correctly. Very weird.

Publié : 16/07/2023 7:07 pm
lfachaux
(@lfachaux)
Active Member
RE: Mk4 screen goes blank after some time

I canceled my order today

ESD issue --> Bad design, move the cables is a workaround , not a solution.

I'll wait few months, before to place, maybe, another order

😉

 

 

Publié : 22/07/2023 9:29 pm
Philipp
(@philipp-8)
Eminent Member
RE: Mk4 screen goes blank after some time

If you are comfortable with unscrewing a few screws and doing 20 minutes of work it's a pretty easy fix, just be careful with the thermal pads on the back of the board, and lay the cables flat so that you don't put pressure on the board when screwing it back in!

Does that still work for you? 🙂

Publié : 23/07/2023 8:52 am
morreale
(@morreale)
Active Member
RE: Mk4 screen goes blank after some time

Brand new kit built today. Screen was fine all through out the config and self test but as soon as I loaded filament and attempted the first print the screen cut off. 

 

Publié : 23/07/2023 9:20 am
morreale
(@morreale)
Active Member
RE: Mk4 screen goes blank after some time

Version B btw

Publié : 23/07/2023 9:33 am
lfachaux
(@lfachaux)
Active Member
RE: Mk4 screen goes blank after some time

Thank you for the feedback @morreale

Bad news.... , this confirms my feeling, I'll have to wait several months to reorder the MK4, or the M4Ks

Fortunately my MK3s is stable

🙁

Publié : 23/07/2023 10:18 am
morreale a aimé
jseyfert3
(@jseyfert3)
Reputable Member
RE: Mk4 screen goes blank after some time

My kit that I just got finished yesterday, with the new PE wire location, works with no issues so far. Powered up, ran through the startup wizard, and then did a 1.5 hour print followed by a 13.3 hour print, followed by a 1.2 hour print. Zero issues seen on the LCD during this time. 

Publié : 23/07/2023 7:59 pm
morreale a aimé
Philipp
(@philipp-8)
Eminent Member
RE: Mk4 screen goes blank after some time

The support thinks the xLCD might have been damaged in transit and are sending me a new one. I've had it not go out for several hours, sometimes it shuts off after a few minutes. I am going to tell you whether the new one works or not.

Publié : 23/07/2023 8:06 pm
lfachaux
(@lfachaux)
Active Member
RE: Mk4 screen goes blank after some time

@ jseyfert3, it's a good news

As the issue is not fixed for @morreale (Revision B) , I'm not confident about the solution to solve problem (ESD/EMI ?)

I have already encountered this kind of problem in one of my design, and I solved the issue with an oval ferrite

 

Someone could give me the width of the ribbon cable ?  

Unfortunately use a ferrite involve to build another ribbon cable with the rights connectors   🙁

I'll prepare the cable before to receive my new order, in case of ..... 

 

 

 

 

Publié : 24/07/2023 8:00 am
Brandon
(@brandon-4)
Active Member
RE: Mk4 screen goes blank after some time

@lfachaux - the ribbon is 30mm wide. It divides after a centimeter or two  into two 15mm wide sections.

The connector is 34mm x 5.2mm x 5.2mm, except there's a little side indicator thing that's an extra 4mm down on one end.

Please do let me know if your ferrite idea works. My MK4 is mostly unusable as things are, which is a real shame because the one test print I convinced it to start more or less blind came out fabulously. Big fan of the load cell, works like a charm! Just want a working display.

Publié : 25/07/2023 6:30 am
lfachaux
(@lfachaux)
Active Member
RE: Mk4 screen goes blank after some time

Thank you very much @Brandon

I found the parts

The connectors :

https://www.te.com/usa-en/product-2-215083-4.html   -> TE Connectivity micro-match , pitch 1.27 (same as the ribbon cable)

The Ribbon cable

-> 24 channels divided by 2 -> Ribbon 2x12 ways with a pitch 1.27  AWG 28

The ferrite :

There are several options, openable or not (with the first option, we don't need to build a new cable, but we need more space for the ferrite) 

https://uk.rs-online.com/web/c/?searchTerm=ferrite+flat+cable

I have in stock a lot of parts with a range of frequency that should help to fix the issue.

@Brandon  : Can you give me the length of the cable ? Thank you for your support 😉

 

 

Publié : 25/07/2023 7:04 am
miroslav.h4
(@miroslav-h4)
Honorable Member
RE: Mk4 screen goes blank after some time

And what about trying this kernel: https://uk.farnell.com/wurth-elektronik/7427246/ferrite-core-flat-cable-33mm/dp/1635628 The core is split, so there is no need to disassemble the connectors.

Publié : 25/07/2023 7:22 am
sole4y
(@sole4y)
Active Member
RE: Mk4 screen goes blank after some time

Guys maybe I found out what it is in my case. When I am moving the cable in connector in the lcd part, sometimes it works. I am doing it when the printer is turned on. When I am actively pulling the cable it mostly works. 

So in my case it looks like there is some problem in the soldering on the connector on the lcd part or problem in the connector itself or something. 

Publié : 25/07/2023 7:32 am
Neolker
(@neolker)
Membre
RE: Mk4 screen goes blank after some time

Hi,

EMC Expert here. The ferrite bead for flat ribbon cable is the last option, when you solving EMC problem and you must exactly know what are you doing. It's more likely there's some connection problem that the test didn't pick up.

Publié : 25/07/2023 7:52 am
miroslav.h4
(@miroslav-h4)
Honorable Member
RE: Mk4 screen goes blank after some time

OK. Může být dobrý nápad oddělit kabel motoru a displeje a vést je co nejdále od sebe. Případ se také týká PE vodiče (zelenožlutého) probíhajícího paralelně s kabelem displeje. Jen Bůh ví, jaké rušení může probíhat podél tohoto drátu. A možná je chyba v designu Buddy, kdy jsou jednotlivé konektory nepohodlně umístěny a je zbytečně zkřížený kabel.

Publié : 25/07/2023 8:12 am
Neolker
(@neolker)
Membre
RE: Mk4 screen goes blank after some time

EMC problémy jsou vždy problém layoutu, ať už PCB nebo kabeláže. Vždy je fajn udělat "krok zpátky" a podívat se na to z širší perspektivy, ale většinou je to fakt jen problém spojení nějakého pinu na konektoru anebo vadné kondenzátory. To se stane, že dodavatel dodá špatnou šarži, která nepochytá dostatešně napěťové špičky z rušení apod. Nicméně bez pořádné analýzy a měření tu můžeme jen věštit z křišťálové koule.

Publié : 25/07/2023 8:28 am
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