Author Topic: Screen too dark, almost can't see anything.  (Read 1209 times)

Spyd (OP)

  • Posts: 3
Screen too dark, almost can't see anything.
« on: February 24, 2021, 11:02:42 pm »
I just got a CoolBaby RS-90, branded by "Mars gaming" (product page: https://www.marsgaming.eu/en/retro/mrb-portable-retro-console_mrbb). As I guessed it's just a rebranding, I used the pinned guide to install OpenDingux.
Everything worked fine, except that since the first message from the flasher, everything shown on screen is extremely dark, to the point to having to tilt the console to be able to read the texts on screen.
I thought it was something related to brightness, so after installing I tried in the configuration with several brightness levels, but none fixed the problem; I can see the brightness change, but the displayed image is still too dark.
Then I thought maybe I have a 3.0 version, so I started from the beginning, but this time I used the 3.0 flasher, it installed OpenDingux ok, but with the exact same screen problem.
Then I tried updating OpenDingux downloading the latest OPK file, it installed fine, but the problem persist, but with the added problem that now I'm unable to copy files from the computer (it tries, does nothing for several seconds and then the USB device gets disconnected from the computer).
Another thing I noticed, is that on none of the versions of OpenDingux I can see the contents of the microSD card. It's an old 128Mb card formatted to FAT32. Do I have to format it another way?

Please help, as I don't have access to the original firmware, and while that one was extremely bad, at least the screen showed bright and colorful.
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pcercuei

  • Posts: 1728
    • My devblog
Re: Screen too dark, almost can't see anything.
« Reply #1 on: February 25, 2021, 04:07:22 pm »
Wow... That looks bad. Maybe it has a different screen that requires a different driver. Unfortunately there's not much I can do here...

About your SD card: try to use a third-party program to format it. Some SD cards come pre-formatted without a partition table, it needs to be formatted properly to work with OpenDingux.
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Spyd (OP)

  • Posts: 3
Re: Screen too dark, almost can't see anything.
« Reply #2 on: February 25, 2021, 08:03:38 pm »
I also think that the problem is that my RS-90 uses a new screen that it's not fully compatible with the one installed on other versions of the RS-90.
I happen to have another one, I didn't want to open it because it's supposed to be a gift for someone else, but I did to have a comparison photo (attached).
I don't know if it's possible, but I wonder if using the flash tools, can I dump the stock firmware and/or file system to extract the driver used by the stock firmware? Or at least to flash and return to stock the one where I installed OpenDingux?
I contacted the maker, but I'm fairly sure they won't send me any firmware, seeing how difficult is to flash it.
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pcercuei

  • Posts: 1728
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Re: Screen too dark, almost can't see anything.
« Reply #3 on: February 25, 2021, 10:07:57 pm »
It would have been possible to dump the old firmware before flashing OpenDingux, now it's too late. But it wouldn't have given much information anyway.

I'd buy one to test, but they don't ship to my region :(
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Spyd (OP)

  • Posts: 3
Re: Screen too dark, almost can't see anything.
« Reply #4 on: February 25, 2021, 10:35:16 pm »
I do have one with the stock firmware. How do I dump it?
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pcercuei

  • Posts: 1728
    • My devblog
Re: Screen too dark, almost can't see anything.
« Reply #5 on: February 25, 2021, 10:56:10 pm »
Well it's really not trivial, it involves booting a custom-crafted Linux kernel over USB. And again, it wouldn't give much information.
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v47

  • Posts: 238
Re: Screen too dark, almost can't see anything.
« Reply #6 on: March 01, 2021, 12:12:35 pm »
I'd be willing to donate a few bucks should there be an effort to get one unit to pcercuei.
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Muki__83

  • Posts: 18
Re: Screen too dark, almost can't see anything.
« Reply #7 on: March 31, 2021, 07:28:02 am »
Hi, in the past i read a post, in which it was specified that some PCB had a wrong resistor, look on the forums and on the web, it could be your case.


here the post
https://steward-fu.github.io/website/handheld/rs90/fix_color.htm
« Last Edit: March 31, 2021, 07:41:43 am by Muki__83 »
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