Awesome news guys, i've been going months without the N900 working and utterly fed up with it until tonight, i finally took a crack at what i thought the error was and it fired right back up with sim card recognition, fast boot and all phone function working (Its still under trial though! but i believe there is an even more perminent fix to what i've done! AND, it doesnt cost a penny!

I need owners to try this fix and report back to this thread please! if its not software and external hardware (Antenna) then its more then likely a symptom of cracked solder within the board (From what i read at the time, solder cracking due to heavy impact.)

I believe the issue and location of damage solder could be different for people, but heres how i've fixed mine.

Tools :

1 x Hammer
1 x Fine Point AWL screwdriver in micro precision screwdriver set (Tesco's about 3 quid IIRC) however a micro phillips should perform too, as well as a nail!

Step 1 :
Take buggered N900



Step 2:
Remove back and battery of N900


Step 3: Remove Sim Card




Step 4: Inspect image below, now with your screwdriver/AWL/Nail, gently impact the metal contacts in the image until you put a small dink in them, apply some pressure as the dink needs to be notable, however DO not put a hole through your N900, Otherwise your in trouble (Well maybe not).

Hit the parts CIRCLED IN RED!, You must hit the contacts in their respective centres, i'm not responsible for any damage, but i assure you my N900 is correctly WORKING! (so far) its down to you whether you want to attempt this, i must say though, shock could cause further damage, maybe even the screen! mine didnt thankfully :P





Step 5: Re-assemble and power device up.



Got this call perfectly timed as soon as i booted!

Step 6: Your sim and signal should be found and operating normally, give your dusty N900 time to adjust, mine was up to something and i have no idea what!




Please if you have a lifeless N900, try this mehod! i have a second method that runs on from this that i will try if my N900 decides to fail again!

Will keep you posted guys!

- Migs


Edit : Update guys, its had the odd drop out, im thinking theirs more contact points under the sim mount support, will have a look later, for now people SHOULD start seing telephony increase! (We can work on it !

I stopped reading when I saw "1 x Hammer"

did you get a white case for it? looks good.

You'l be taking a hammer to it if you end up with this problem, believe me .

Anyone tried this yet? mines working but flakes out under heavy arial usage, i think i may need a new antenna block!

And yeah my n900 is white, took a while to convert everything properly though.

Erm, why hammering? Isn't it better solution to try resoldering? After all, those parts are relatively big, it's not SoC rebailling

Anyway, thanks for sharing it, nevertheless!

/Estel

Sorry This solution didn't fix my n900. I tried this on my n900 at three times but it couldn't fix my all telephony functions issue . I am waiting new solutions for this error.

Sorry for my bad english.

Thanks Advance

Best Regards

So far, the paper-between-battery-and-SIM trick is working for me. Remove paper = error, add paper back = no error.

There are many topics about this problem.
In my case, my phone gets no SIM icon when the battery is low, but it used to get no SIM icon even when it was almost full (more than 70%).
Usually the problem appeared when I used data (skype call over mobile data (not wifi) was the best way to end up with no telephony functions). It's not happening regularly, but it has something to do with low battery, high cpu load - even opening conversation made it happen (maybe the phone is overheated, or the SIM contacts are overheated).
When the problem occured. I was not able to connect to gprs data immediately after that, I finished in no SIM icon loop. When I waited 5 minutes and let the phone connect to network automatically, everything was good.

What kind of paper do you use under the battery? And how big is that? Is it under the whole battery space or just where the SIM card is located?
I'd like to try some more solutions, cause I have no doubt that in my case it'll get worse (as it did before). Any help appreciated.

Not sure if you have oc'd your device, but if you are, You might frequently loose the SIM when battery is near empty if your voltages are too low.

For diagnostic purposes enable the nokia default voltage profile and try reproducing the issues and report back.

I have not currently oc'd, phone is recently flashed with some programs installed. I even tried to flash the phone and not to install anything, just used built in skype. Even with nothing installed the no SIM icon still appeared and I sent the phone to repair center - they did not fix anything, because the didn't happen to them. But I didn't use the phone for 3 weeks and it for few days it was ok. I think, that this is somehow connected to heat production of the phone, some parts may be overheated and it's connected to signal strength. When I was in Prague (connected to 3g), I didn't get this error all the day, even when the baterry was low, but on the way from Pilsen to Prague it happened repeatedly. Signal was not weak (100% all the time), but it had to be somehow bad, so the SIM contact was lost. I'm not really sure why this happens and can't even reproduce situation, when the error happens at 100%. It just happens randomly, which is weird.