T28 problem after change PA. - GSM-Forum

chris_ua · 10-04-2002, 23:16

Hi!

I have 3 boards of T28 with the same problem:
They all were dead due to PA fault (the signal strength is weak in our region, so this kind of fault is rather common).
After removal of PA they all were working (swiched on with no problem at least).
After placement of a new PA they don't power on again, and the battery became fully discharged in few minutes. At the battery contacts I found a short circuit (no resistance).
Tried to remove the PA but the SC still remain on battery contacts.

Please, advise me what should I check to resolve this prob? Maybe something was killed by faulty or badly soldered PA but can't figure out what exactly.

Thanx in advance.

olegario · 10-05-2002, 07:36

try to resolder litle black resistor - it will off PA from PCB(power I mean) . if your phone still short - check zone around Power BGA, check/change capasitor's and diode near Inductor .

good luck

olegario · 10-05-2002, 07:37

this resistor is on the left from PA

10-04-2002, 23:16	#1 (permalink)
chris_ua Freak Poster Join Date: Jan 2001 Location: Uzhgorod, Ukraine Age: 47 Posts: 305 Member: 3023 Status: Offline Thanks Meter: 1	T28 problem after change PA. Hi! I have 3 boards of T28 with the same problem: They all were dead due to PA fault (the signal strength is weak in our region, so this kind of fault is rather common). After removal of PA they all were working (swiched on with no problem at least). After placement of a new PA they don't power on again, and the battery became fully discharged in few minutes. At the battery contacts I found a short circuit (no resistance). Tried to remove the PA but the SC still remain on battery contacts. Please, advise me what should I check to resolve this prob? Maybe something was killed by faulty or badly soldered PA but can't figure out what exactly. Thanx in advance.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
6310 start up problem after change pa	gsm_style	Nokia Hardware & Hardware Repair	3	11-09-2004 21:08
Big problem After Changing PA	Black-Axe	Nokia Hardware & Hardware Repair	11	11-22-2002 06:34
T28s random signal after changing PA- help pls	chrisro	Sony Ericsson Hardware Repair	7	11-19-2001 18:45
T28s random signal after changing PA	chrisro	Old Ericsson Phones & Sony Phones	3	11-15-2001 19:51
T28 No access after change PA	fm-gsm	Sony Ericsson Hardware Repair	4	11-03-2001 18:32

10-05-2002, 07:36	#2 (permalink)
olegario Insane Poster Join Date: Sep 2002 Location: lithuania Age: 51 Posts: 78 Member: 15224 Status: Offline Thanks Meter: 0	try to resolder litle black resistor - it will off PA from PCB(power I mean) . if your phone still short - check zone around Power BGA, check/change capasitor's and diode near Inductor . good luck

10-05-2002, 07:37	#3 (permalink)
olegario Insane Poster Join Date: Sep 2002 Location: lithuania Age: 51 Posts: 78 Member: 15224 Status: Offline Thanks Meter: 0	this resistor is on the left from PA