MobileRead Forums - View Single Post - Troubleshooting Old Kindle 5 classic screen

mergen3107 · 04-13-2020, 06:27 PM

@DjKlimo88

OK, so only IF the screen was replaced, this thing might help:
Jailbreak your Kindle, have access to write files (`mntroot rw` command).
The file is /sys/devices/platform/eink_fb.0/vcom
It contains a number, I don't remember format, just keep it the same. It is the screen's waveform voltage. Like, 2.50 Volts, or similar within a small step. Remember or write down this default (just in case).
Change this number by a small step, restart Kindle (having USBNetwork to autostart just in case, so can revert the value bacl to its default), and see if it helped, repeat.

Otherwise, if it is really a controller problem, you can still try to tweak this file, but it will only allow you to adjust the screen/contrast quality slightly, not until the best quality it once had. Such a case was on 4PDA forum a while ago (it is in Russian, so please use Google Translate).

04-13-2020, 06:27 PM	#6
mergen3107 Wizard Posts: 1,525 Karma: 5000046 Join Date: Feb 2012 Location: Cape Canaveral Device: Kindle Scribe	@DjKlimo88 OK, so only IF the screen was replaced, this thing might help: Jailbreak your Kindle, have access to write files (`mntroot rw` command). The file is /sys/devices/platform/eink_fb.0/vcom It contains a number, I don't remember format, just keep it the same. It is the screen's waveform voltage. Like, 2.50 Volts, or similar within a small step. Remember or write down this default (just in case). Change this number by a small step, restart Kindle (having USBNetwork to autostart just in case, so can revert the value bacl to its default), and see if it helped, repeat. Otherwise, if it is really a controller problem, you can still try to tweak this file, but it will only allow you to adjust the screen/contrast quality slightly, not until the best quality it once had. Such a case was on 4PDA forum a while ago (it is in Russian, so please use Google Translate). Last edited by mergen3107; 04-13-2020 at 06:29 PM.