8850 no network

[!_-_-Nokia-_-_!]

Hi,

I've get a faulty 8850. It has Network (D and E) only shortly after switching on. Not make a telephone call possibly. Himself look for it at a manual Network search stupid and stupid. I guess the PA. I have opened it once and pressed with the finger of the PA. After that it no Network, not after switching on briefly now.

What could exactly be faulty?

Sorry, for my bad English

[crashynot]

hi there
you have to replace PA and antena switch
and it will be ok
but you heed hardware for that

[sergo_zmeia]

Yes..PA could be foulty....just a tip..phone founds network with DSP/ digital signal processor/ which is HAGAR in NOKIA phones...
Good luck!
Sergo_Zmeia

[p.barker.3646]

i have a simalar problem with my 8850

the signal sometimes drops out for no reason 90% of the time its ok

if i go to an area of low signal (2 bars or less) the signal drops completely and dont come back wiv a bash on the table

anyone got any idears????

[warren]

hello,

try cleaning the antenna points and reheat the antenna switch, might as well check the hagar also.

regards,

warren

[p.barker.3646]

how do i check the hagar??

im not to good on the hardware side

thanks - pete

[sergo_zmeia]

@p.barker.3646, use eeprom tools 3.1 and 4.0....they will give U a point...
Regards!
Sergo_Zmeia

[p.barker.3646]

many thanks for your help people

i will post back when i have chance to try all options

would it not have anything to do with calibration or does that only apply after changing components??

i have fully flashed it (eeprom and all)

[marky752000]

Fully flashing will or should calibrate the PA, but if it's F*~ked then it won't help.

When you manualy search for networks, how long is the search?

If it 20 seconds or less then Duplexer (antenna switch) may be faulty, if its a good 30s to 1 min then antenna sw should be ok and your problem is with the Hager, PA and Cobba.

Reflow Hager and Cobba. connect it to a bench power supply, and power on see what current it draws. once the phone has booted and its just about to show network, the current should peak at 0.235mA before droping to 0.000, anything else would surgest a faulty PA

Hope this helps


BR

Mark

[p.barker.3646]

if its in a state where it has got signal then it probably takes a 1min for a net search

but if it is playin up and got no signal than it takes ages

i think im out of my depth with this one as i dont have the tools or the skill for reflowing pcb's

unless were talkin wrap it in tin foil and put it under a heat lamp

[marky752000]

Tin foil and a toaster might work

but I wouldn't try it

BR

Mark

[p.barker.3646]

so is reflowing easy to do???

is it a case of just using a heat gun or have ya gotta touch each pin of each component with a soldering iron???

im assuming it aint the latter because i carnt even see the pins on most of the ic's

[marky752000]

You need a hot air station, you could use a hot air gun, but if the air flow is too strong it will blow other components off the PCB and cause you more problems

[p.barker.3646]

i see :S

i think i had better leave it then

or go out and spend a few grand on tools

i wanna get into fixin phones properly but i have not got the proper training

everythin i know is normally through blowing things lmao

now then where is that toster