[Android Head-Units] kaween:
HA ! a kindred spirit. :)

HI chris, long time no see. And YES, I couldn't agree more. I'll try it tomorrow, too late now. Thank you !

---------- Post added at 11:06 PM ---------- Previous post was at 10:38 PM ----------

Hmm. When it freezes and your Radio tuner is working, do you still hear the radio part tuner ?

Reason why I ask : there are a multitude of reasons for this kind of behavior. Depending on what happens your answers may help to indentify the issue.

I've had severe hardware issues with my own AN21 too and did quite a lot of experimenting on the hardware trying to determine cause and rectifying the issues, including tyring to prevent the repetition of these issues in the future, so I'm not completly clueless here. :)

1) the "screen freezes up" looks and feels like an overheating of the ARM board. As I wrote in the past and as it has been confirmed by other members later, the ARM board becomes ..... hot. And it is NOT cooled by anything. The airflow in these units is .... bad. It is not unthinkable your ARM board (the cpu board) has developed an issue due to thermal load : it would fit the "it works for some time and gives up on me after a while". The ARM goes above 60°C Centigrade in no time, and that without any heavy load at all and OUTSIDE a dashboard. Imagine what temperatures this cpu gets tosted at when really WORKING (Navi, DVD decoding, god-knows-what) in a closed dashboard.

Hence my "add cooling mod" that I wrote in the disassembly guide.

2) this behavior reminds me of the typical S150/S100-go-dead-because-of-cpu-overheating after installing Android 4.0x instead of WinCE or Android 2.3 : there too, the higher cpu load resulted in "sudden death" of the units because of the higher temperature. Same kind of stuff happened there. Maybe the same solution can be used. (ARM reflow - any better electronics shop should be able to do that for you)

3) but also the MCU chip itself COULD be the reason. Hence my question of the Radio tuner keeps outputting when the unit goes down : if yes, you can be relativly sure the ARM is at fault, as the radio tuner chip is driven by the MCU and works pretty much independantly of the ARM. If however the radio tuner stops working alltogether and no radio sound can be heard when it crashes, the MCU board itself is probably damaged, or the MCU-chip itself has developed a problem. If the radio tuner still makes sound, and you can still change things like volume or even changing channel (using SWC or whatever) the problem will be in the LCD driver board.

4) luckely, the AN21 mainboards can be found at a reasonable price these days. I've know them to be on offer for 60USD exclu P&P. Replacing the board is very easy and anyone who can use a screwdriver without poking an eye out can do it. If push comes to shove, I can put you in contact with a Chinese seller who has AN21 boards on offer, but as there are several different AN21 layouts, it would be useful to know what your specific board looks like first.

5) it is absolutly possible the shock of the accident caused a microfracture on a solder weld. Again, reflowing the board would solve this. Again, the "it happens after some time running" fits this : a cold joint or broken solder point will do just that as it looses contact as the component in question gets hotter and one of the contacts detaches itself from the PCB-trace. There are a couple of thousands of solder joints (both visable and invisable as several will be under the electronics components themselves) and trying to find that is .... difficult. Hence it is important to know if the problem is more likely to be the ARM board, the MCU board or even the LCD driver board. This calls for a electronics geek, a testbench and a lot of cold-spray to hunt down the possible culprit on a PCB.

What to do next depends on the answers on these questions, and also on what you yourself can do (this being a geek-oriented forum, I guess there will be several people who are quite comfortable with stuff like board reflows and smd work) or if you know somebody who can do stuff like that for you. If push comes to shove and no other solution is possible, replacing the ARM/MCU board will probably be the last resort -which sounds far more dramatic than it is, really. Just ask Cool_Head. :D-

Good luck, and let us know your findings. We"ll take it from there.