Screen flicker on LCD at dimmest setting?

Thank you for answer. At this moment my AA1 is to my wife, so I don't have one to test all that. I'm interested to solve this problem because I want to buy another one for me.

 

Well, I've repeated experiment with oscilloscope attached.
So, switching to PWM mode reduce 5V line unstability from ~150mV to ~5..10mV.
And this time I see no flickering!
Maybe it depends on battery charging level (it was near 100% first time, 75..40% second time), or some another reasons - don't know yet..

 

Good news UncleDim. Thank you for testing that. So, there are some hopes about screen flicker. The next thing if we need is to be able to set lowes brightness with new bios. I tried before to change tha screen brightness table on bios 3304, and after programming the flash the notebook did not start any more. I removed the flash chip and programmed it with a universal programmer. After that the AA1 starts again ok, but with bios 3304 and with brightness table acording this version. If someone knows how to change the brightness table with new bioses please tell as too how to do that.

 

Offtopic. )
I tried to play with SPD data for onboard memory (wanted to disable it), with the same result and same solution

 

A couple of words about efficiency loss.
Initial: battery 100% charged
Then putting AAO in S3 mode (sleep, suspend-to-RAM) for 7 hours.
Waking up, checking battery meter:

SKIP mode - 90%
PWM mode - 71%

 

There is a power loss where in the PWM mode. Acordingly with the PWM mode the current draw increase when light load. This current is from 10 mA to 50 mA. And the same current increase will be even when the AA1 is in shutdown/hybernation because as I remember the 5V supply works all the time while battery or AC connected. So, that will use the battery power even when the AA1 is power off. I think there will need supplimentary circuit to switch from PWM to SKIP while the notebook is stand by, shut down or hybernation.

 

Just connect external display (or 3 75-OHm resistors between RGB and GND contacts of VGA connector) before turning AA1 on.