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Sony Ericsson Hardware Repair Post here your Hardware Repairing Hints or Problems with SonyEricsson and Sony Phones. |
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12-22-2002, 23:26 | #1 (permalink) |
Junior Member Join Date: Oct 2002 Location: Italy Age: 53
Posts: 14
Member: 16704 Status: Offline Thanks Meter: 1 | T28 Network Problem I have a lot of T28 ,T20, T29, A2618 that after ''power on'' show the operator's name but the no signal bar is present on the display. If i make a call the phone shows ''network problem'' and sometimes after a few minutes the display shows NO ACCESS. I have changed PA and antenna switch but the defect still remains , i also tried to rework the phone's solders with hot air .Does anybody Know what the problem is? Thanks |
12-23-2002, 18:01 | #4 (permalink) |
No Life Poster Join Date: Jun 2002 Location: Iran Age: 47
Posts: 1,082
Member: 12724 Status: Offline Thanks Meter: 30 | dear mate. the RF processor is the same thing that you may know as PA. try to change it. the problem will be removed if you replace it well Good louck.LIGHt |
12-23-2002, 18:30 | #5 (permalink) |
No Life Poster Join Date: Dec 2001 Location: United Arab Emirates, Dubai Age: 52
Posts: 1,269
Member: 7751 Status: Offline Thanks Meter: 74 | @unoche The RF Signal processor is called "N234" The PA is called "N400". You'll see this numbers from the service manaul, find the board layout and you'll see the placement. The RF Processor as I remember (correct me if I'm wrong) it, is also called IF Module? Also try to reflow the MMCC "Multi Mode Converter Circuit", it's located just under the CPU called "N800". But please be aware if you chnage this chip, you'll need to recalibrate Radio, Voltage and current of the phone, so better leave it on. This chip also causes "No power on" sometimes The RF Processor is the big square IC with visible legs, no solder "under the chip", and it'll take a steady hand to change it, better first try to reflow it with good flux, have seen quite some T28 with this chip badly soldered. (Note: This chip is the FIRST chip I check if I have a T28 "no signal". In 60% of the cases this is the one faulty in my exsperince) @GSMLight I must strongly disagree with you that the PA=RF Signal Proceesor. Regards |
12-23-2002, 18:50 | #6 (permalink) |
No Life Poster Join Date: Nov 2001 Location: Slovakia
Posts: 1,005
Member: 7586 Status: Offline Thanks Meter: 11 | I have same problem . I have several r320, t28 ... with NO NETWORK, I changed RF signal proc. but still no network. Do i need to reflash phone or what? What temperature is suitable for RF signal proces not to kill it ? b.r. Pali |
12-24-2002, 14:54 | #8 (permalink) |
No Life Poster Join Date: Nov 2001 Location: Slovakia
Posts: 1,005
Member: 7586 Status: Offline Thanks Meter: 11 | ??? I know that PA is not RF sig. proc.. I'm just asking what should be problem. I changed on R320 with no network and still no network. I changed for new one. Which temperature is good for it ? Do i need flash after change? b.r. Pali |
12-26-2002, 00:48 | #9 (permalink) |
Freak Poster Join Date: Dec 2002 Location: Serbia Age: 48
Posts: 148
Member: 18812 Status: Offline Thanks Meter: 1 | For pali !!! Maby your problem is not in RF sig.proc. try contiue with swither and at the end change PA. !!! MUST WORK !!! Send results P.S. RF is first thing in most cases that should be changed but not always mightym |
12-26-2002, 09:27 | #10 (permalink) |
No Life Poster Join Date: Nov 2001 Location: Slovakia
Posts: 1,005
Member: 7586 Status: Offline Thanks Meter: 11 | @mightym Do u know how for sure can i check if it is or not RF sig proc ? i think 300C will kill RF sig. proc or not ? So what temperature is ok for changing RF sig. procesor ? Is antena switch compactible with any other , for example from any nokia ? thanx for reply. b.r. Pali |
12-26-2002, 12:19 | #12 (permalink) |
Freak Poster Join Date: Dec 2002 Location: Serbia Age: 48
Posts: 148
Member: 18812 Status: Offline Thanks Meter: 1 | Yes it compatibile !!! I change it all ok but with litle less signal streinght,but It have one more problem paralel with switch About temperature I work with 327-335 C and nothing happend to me, all works never kill anything !!! But for SIEMENS CPU be extra carefull never heat IC in the midle you will brake it in the sec.also sagem IC-s NOKIA,ERICSSON, PHILIPS,ect ect no problem on that temperature All the best mightym |
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