Sansa Fuze V2 white screen on low-ish battery

[screenclene]

I have a Sansa Fuze v2, that has been used for a very long time now (bought it new when they were first out, and used it almost daily ever since).
Now, when the battery gets low-ish (maybe about 45%), I start to get intermittent screen problems, including:

Screen inversion (everything appears like it was in a mirror).
White screen on boot up.

I'm not 100% sure, but I think this started happening after frequency scaling modifications were released.  Its hard be sure though because it takes a long time to get the battery low after I've charged it.

So on 22nd April, I did this:
I took the memory card out, reformatted the Fuze, installed the latest version of Rockbox, charged it fully. 

This week the problem happened again.  It could it be that my Fuze is dying .  Or could there be a problem with the latest power saving features on my player?

[Mihail Zenkov]

Next time (when you got this problem again) try check any version of rockbox before frequency scaling changes with same (or lower)  battery level.

[saratoga]

There are 3 things worth checking.  Voltage scaling, frequency scaling, and the changes we made to clocking that are needed to enable frequency scaling. 

Here is a version with voltage scaling disabled:

web.mit.edu/mgg6/www/rockbox-disableHAVE_ADJUSTABLE_CPU_VOLTAGE.7z

If you still have the problem, you can try this build which has both frequency and voltage scaling disabled:

http://web.mit.edu/mgg6/www/rockbox-disable_both.7z

If that still has the problem, you'd have to try something older.  What was the version you were running before 22 April?  It may also eliminate the need to test some of those builds depending on how old it was.

[screenclene]

Thanks, I will try the alternative firmwares soon.

The problem occurred yesterday again , using the 22nd April version.
Rockbox showed 77% available power!
First symptom was the inverted/mirrored screen
Then I rebooted and got a white screen (twice)

I managed to reboot to the sandisk firmware, then when rebooted I back to Rockbox the player was OK.

The problems originally occurred on my fuze after frequency scaling was implemented (I think), but definitely before voltage scaling was implemented.

[screenclene]

Ok, a further update.  I still haven't tried the alternative firmware without the power saving features.  I thought I'd push my Fuze v2 to its limits by using it till it completely stopped working.
I got a total run time of about 24 hours.  The battery went down to about 7%. After that, Rockbox would shut down claiming a low battery whenever I did anything other than listen to mp3's.

I saw a few screen problems after battery capacity was less than 70%:
A white screen twice.  But I shut-down and left it for 30 secs, then rebooted and it was OK.
A horizontal block of yellow/green speckles across the screen appearing for a perhaps 1 or 2 seconds.  This happened  pretty much every time I started listening or moved from the menu to the WPS, or from the WPS back to the menu.

I mostly just listened to it, deliberately not interacting with the screen at all.
I am certain that the problems I have experienced with it only occur when the display is active.  If I just listen but don't look everything is fine.  But if I look at the display and try to interact with the player it has screen related problems.  If this has anything to do with power, then I suspect that it the extra drain of power when operating the screen that pushes it over the edge and causes problems.

[screenclene]

OK, I've pretty much decided that my Sansa Fuze v2 has to be retired.  The white screen occurs way too often now, and it occurs on old Rockbox builds where it used to work perfectly before.
A really sad day for a little player that has served me almost daily since I bought it new on a trip to the US, perhaps 5 to 8 years ago!

My next player will be a tiny 4gb Sansa clip zip.  I may have to carry a large magnifying glass with me so that I can use it though!