Flickering lights 2.8.1

[Griu]

Originally Posted by geekmaster

I think you did not get knc1's (or my) concept of "random". We mean an APERIODIC flicker, not a "random chance of occurance". We are talking about the appearance of the flicker (short time scale), not about its existence (longer time scale).

Random (aperiodic) flicker is likely a cracked or poor electrical connection (and as knc1 mentioned, would probably be affected by vibration). Periodic flicker (i.e. a fast regular blink) would more likely be caused by failing components as I described in a previous post. Failing components might be allowing a local radio station carrier frequency to ring-modulate your frontpanel LEDs, for example. An oscilloscope you help diagnose what is going on, while freezing components (as knc1 suggested) may help locate the specific failing device.

Oh. I get it now. Then yes, it is random, the flickering does not have a pattern. It even seems to stop if I go to MAX for a minute and then go back to 10 (Since sometimes it also happens when it's on 10).

But notice that even when its on MAX the real light is not going past 10.

[geekmaster]

Originally Posted by Griu

Oh. I get it now. Then yes, it is random, the flickering does not have a pattern. It even seems to stop if I go to MAX for a minute and then go back to 10 (Since sometimes it also happens when it's on 10).

But notice that even when its on MAX the real light is not going past 10.

That sounds like a potential thermal instability as well, either in a component or a poor solder joint or cracked trace.

Modern lead-free solder is famous for that. It is brittle and some solder joints can break in shipping, giving them a friction contact rather that a solid solder joint. Thermal expansion can affect the symptoms, as well as shaking or vibration.

A solder reflow with a heat-gun is the typical fix, but needs an aluminum foil mask to protect all but the part that needs reflowing (melting the solder to flow and resolidfy across the crack). Do not get heat on the glass screen if you are interested in trying such a fix, but I would just use the kindle with the frontlight low enough to avoid flicker, and not risk destroying the kindle in an attempt to fix it.

[Griu]

Originally Posted by geekmaster

That sounds like a potential thermal instability as well, either in a component or a poor solder joint or cracked trace.

Modern lead-free solder is famous for that. It is brittle and some solder joints can break in shipping, giving them a friction contact rather that a solid solder joint. Thermal expansion can affect the symptoms, as well as shaking or vibration.

A solder reflow with a heat-gun is the typical fix, but needs an aluminum foil mask to protect all but the part that needs reflowing (melting to solder to flow and resolidfy across the crack). Do not get heat on the glass screen if you are interested in trying such a fix, but I would just use the kindle with the frontlight low enough to avoid flicker, and not risk destroying the kindle in an attempt to fix it.

Yeah, thanks. I'll do that, since I can still use it in the dark, I don't want it to get worst.

[knc1]

Originally Posted by geekmaster

- - - -
A solder reflow with a heat-gun is the typical fix, but needs an aluminum foil mask to protect all but the part that needs reflowing (melting the solder to flow and resolidfy across the crack). Do not get heat on the glass screen if you are interested in trying such a fix, but I would just use the kindle with the frontlight low enough to avoid flicker, and not risk destroying the kindle in an attempt to fix it.

You probably want to avoid squirting that -65 degree spray on the e-ink display.
I wouldn't even try to guess what (if anything) that might do to the display.

[Griu]

Originally Posted by knc1

You probably want to avoid squirting that -65 degree spray on the e-ink display.
I wouldn't even try to guess what (if anything) that might do to the display.

Got it.

[geekmaster]

Originally Posted by knc1

You probably want to avoid squirting that -65 degree spray on the e-ink display.
I wouldn't even try to guess what (if anything) that might do to the display.

The eink waveforms are not calibrated for -65 degrees, and the eink oil viscosity at that temperature would probably require minutes (or hours) to update the display). However, differential temperatures from rapid local expansion (heating) or contraction (cooling) would surely exceed the tensile strength of the glass, and spreading cracks would damage the ITO traces on its surface.

Yeah, too hot or too cold too quickly, bad news. -65 on your skin is bad news too, except when removing warts (though I did burn a wart out with a soldering pencil as a child).