LCD goes blank when power supply fan comes on

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raidtheruins
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LCD goes blank when power supply fan comes on

Post by raidtheruins » Sun Aug 21, 2016 11:09 am

Hey folks,

Happy to have just finished building my Rostock Max v2, my first 3D printer :D

I'm currently printing my fan shrouds, but I've run into an odd issue with my LCD. Part way through my first print, the LCD went blank. Not off, it is still backlit, but nothing shows up, not even the two lines of blocks. The print continued without issue, so it only seems to be the screen itself that's affected. I checked the forums and thought I must have blown a fuse on the RAMBo, but when I turn the machine off, then back on, the LCD operates normally. It has gone blank several times, and it seems pretty random. I've had a print go through completely without it cutting off, and other times it went blank shortly after starting up the machine.

The only thing it seems to possibly tie to is the fan on the power supply itself (not the fan attached to the side plate). It seems to go blank when that fan comes on, and once that happens the LCD won't display until the machine is power cycled.

I checked my connections and nothing seemed to be obviously loose or out of place.
Any idea what's going on? Could this still be a fuse issue?

EDIT: I just discovered that disconnecting and reconnecting within MatterControl gets the screen to work again if it's blank. Still not sure why

Eric
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Re: LCD goes blank when power supply fan comes on

Post by Eric » Sun Aug 21, 2016 10:15 pm

If the backlight is still on, you are still getting power. Furthermore, if the relevant fuse is blown, the rambo is going to stop working too. So it is NOT the fuse.

The fact it worked at all means you've got the cables connected correctly.

Sounds to me like the LCD module is getting into an invalid state somehow, but it works again (for a while) when it gets reintialized. Power cycling and apparently reconnecting cause that to happen.

You could try swapping the A and B cables (both ends) on the LCD display and seeing if the symptoms change at all. If so, then one of the cables is suspect. If not, the cables are probably fine and you've got a marginal LCD module. I'd contact SeeMe about getting a replacement.

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Nylocke
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Re: LCD goes blank when power supply fan comes on

Post by Nylocke » Sun Aug 21, 2016 11:44 pm

I've encountered this before, but its more prevalent on Marlin I think. Do you have any high power/high noise wires crossing the LCD wires? Is the base a bit of a rats nest? I think if theres too much noise the LCD stops displaying the text it was displaying. If you click the push button in or spin the encoder does it make noises/bring back the display?

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Eaglezsoar
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Re: LCD goes blank when power supply fan comes on

Post by Eaglezsoar » Wed Aug 24, 2016 12:39 am

Nylocke is correct that noise on the LCD wires can be a source of problems on the LCD display and SD card reading.
There are flat, fold-able ferrite cores that can put on the wires to the LCD.
They cost $2.70 each and you would need two of them. Here is a link,
http://www.digikey.com/product-detail/e ... ND/2465452
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raidtheruins
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Re: LCD goes blank when power supply fan comes on

Post by raidtheruins » Wed Aug 24, 2016 4:18 pm

Nylocke wrote: If you click the push button in or spin the encoder does it make noises/bring back the display?


It does make noises still but does not bring the screen back.

Eaglezsoar wrote:Nylocke is correct that noise on the LCD wires can be a source of problems on the LCD display and SD card reading.
There are flat, fold-able ferrite cores that can put on the wires to the LCD.
They cost $2.70 each and you would need two of them. Here is a link,
http://www.digikey.com/product-detail/e ... ND/2465452


I ordered up two of these, I'll give them a try when they come in and see if that takes care of it. Thanks!

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