T20 RF processor problem. Very strange! - GSM-Forum

johny3310 · 06-21-2003, 23:12

I have T20 with good signal, but call cannot be connected,
onli silent "click" from speaker.

So, i put new RF processor - and now no signal at all!
So i tried another new RF proessor - again no signal.
I tried to change PA, Ant. switch, Multimode adapter - still no signal.

When i put original RF processor back, i have signal, but cannot connect a call.

I have tested these two new RF processors in good phone - they work OK.
I checked lines on PCB arround RF proc. on my bad phone with microscope - everithing looks fine.

Soldering isn't problem, i am 100% sure about this, i allready
changed more than 50 this chips without problems.

Any idea?

06-21-2003, 23:20

If you have "puk" in speaker, that could be PA, RF proc. , or RX/TX mixer problem.
Usualy, this is coused by bad soldering under PA, or bad RF processor. But in your case, i have no idea at all. . .

marple · 06-23-2003, 23:09

Or try to rehot 1011120/4CR1 sometime is problem in him,because he is multiprocesor for all(mic,speaker,network too),but before all check antena conector,maybe is problem in bad contact...

marple · 06-24-2003, 23:50

Last two days i have more two T20 with "click" in speaker and "searching network",first i rehot DSP and after that i pick up him and make new pins and Legija belive me-they stil work!!

06-26-2003, 00:28

Hm, of course, that can be reason, too.
But, for me, reballing DSP is needed only when you have no sound in speaker.
Shi.ty ericsson phones . . .

gsm-lord · 06-29-2003, 18:47

Quote:

Originally posted by legija
Hm, of course, that can be reason, too.
But, for me, reballing DSP is needed only when you have no sound in speaker.
Shi.ty ericsson phones . . .

for no sound u must reball multimode convertor not dsp

themobileking · 07-02-2003, 19:44

I had many T28's and T20's with this problem ...and frankly ..i tried everything ..PA ...RF processor ....mixer ..antena switch ...antena connector ...software upgrade/flash..finally i gave up ....i could not solve the problem ....but some phones were easy ....i would just change the RF processor and it would work well.....i remember in 2 phones I changed the Power IC and the "click" problem was solved...I thought that i had solved the fault ...but when i tried other phones ...

.....no it was no use ...I have never been able to solve this problem 100%

L_DIM2003 · 07-03-2003, 12:23

Quote:

I had many T28's and T20's with this problem ...and frankly ..i tried everything ..PA ...RF processor ....mixer ..antena switch ...antena connector ...software upgrade/flash..finally i gave up ....i could not solve the problem ....but some phones were easy ....i would just change the RF processor and it would work well.....i remember in 2 phones I changed the Power IC and the "click" problem was solved...I thought that i had solved the fault ...but when i tried other phones ........no it was no use ...I have never been able to solve this problem 100%

yes, you write
this is problem very actually fo 2618/2628 too. very bad phone

marple · 07-05-2003, 00:15

sometime try to rehot flash on A2618 or 2628......look crazy.....but try,dont ask me how but some of them still working!

genocite · 07-06-2003, 09:00

i think cpu also controls signaling and too bad the t2x phones almost had the cpu glued all

arness · 03-03-2004, 23:52

Maybe i`m wrong,but i know there are 2 different versions of boards on T20.
One of them have a type of PWR AMP and a ICRF 11033,like T28,and the other one have another type of PWR AMP,and onether ICRF 3004CR1C,like 1018.Maybe this is the reason for incompatibility.

L_DIM2003 · 03-04-2004, 07:04

yes, there is two different boards for T20/T28

yesterday i had new problem with this is phone (T20)

from this phone i can perfect make call with one operator (tele2), also this phone show perfect parametrs on both bands with gsm tester, but with other operator it can't find net - net on lcd full and drop down, and again... same time phone can find net, but without calling...
i think problem in frequency generator or in sintezator . i think that there is same frequency offset in phone and for different operator this is parameter may be very critical.... for one operator this is offset is wide and phone perfect synchronization with BS, for other operator this is offset little - and fail to connect...

ok, i try change RF, 13 MHz, PA, all cmd arround 13 MHz (varicaps, capacitors...), reflow AD/DA converter, rewrite eeprom (but i think that it not help

), also change sintezator D300...
not help

06-21-2003, 23:12	#1 (permalink)
johny3310 Freak Poster Join Date: Jul 2002 Location: Croatia Age: 49 Posts: 499 Member: 14004 Status: Offline Thanks Meter: 6	T20 RF processor problem. Very strange! I have T20 with good signal, but call cannot be connected, onli silent "click" from speaker. So, i put new RF processor - and now no signal at all! So i tried another new RF proessor - again no signal. I tried to change PA, Ant. switch, Multimode adapter - still no signal. When i put original RF processor back, i have signal, but cannot connect a call. I have tested these two new RF processors in good phone - they work OK. I checked lines on PCB arround RF proc. on my bad phone with microscope - everithing looks fine. Soldering isn't problem, i am 100% sure about this, i allready changed more than 50 this chips without problems. Any idea?

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06-21-2003, 23:20	#2 (permalink)
legija Guest Posts: n/a Member:	If you have "puk" in speaker, that could be PA, RF proc. , or RX/TX mixer problem. Usualy, this is coused by bad soldering under PA, or bad RF processor. But in your case, i have no idea at all. . .

06-23-2003, 23:09	#3 (permalink)
marple No Life Poster Join Date: Mar 2003 Location: Europe Age: 54 Posts: 788 Member: 24581 Status: Offline Thanks Meter: 87	Or try to rehot 1011120/4CR1 sometime is problem in him,because he is multiprocesor for all(mic,speaker,network too),but before all check antena conector,maybe is problem in bad contact...

06-24-2003, 23:50	#4 (permalink)
marple No Life Poster Join Date: Mar 2003 Location: Europe Age: 54 Posts: 788 Member: 24581 Status: Offline Thanks Meter: 87	Last two days i have more two T20 with "click" in speaker and "searching network",first i rehot DSP and after that i pick up him and make new pins and Legija belive me-they stil work!!

06-26-2003, 00:28	#5 (permalink)
legija Guest Posts: n/a Member:	Hm, of course, that can be reason, too. But, for me, reballing DSP is needed only when you have no sound in speaker. Shi.ty ericsson phones . . .

07-02-2003, 19:44	#7 (permalink)
themobileking No Life Poster Join Date: Jun 2001 Location: Uranus Age: 53 Posts: 731 Member: 5072 Status: Offline Thanks Meter: 91	I had many T28's and T20's with this problem ...and frankly ..i tried everything ..PA ...RF processor ....mixer ..antena switch ...antena connector ...software upgrade/flash..finally i gave up ....i could not solve the problem ....but some phones were easy ....i would just change the RF processor and it would work well.....i remember in 2 phones I changed the Power IC and the "click" problem was solved...I thought that i had solved the fault ...but when i tried other phones ........no it was no use ...I have never been able to solve this problem 100%

07-05-2003, 00:15	#9 (permalink)
marple No Life Poster Join Date: Mar 2003 Location: Europe Age: 54 Posts: 788 Member: 24581 Status: Offline Thanks Meter: 87	sometime try to rehot flash on A2618 or 2628......look crazy.....but try,dont ask me how but some of them still working!

07-06-2003, 09:00	#10 (permalink)
genocite No Life Poster Join Date: Jul 2001 Location: md Age: 25 Posts: 761 Member: 5379 Status: Offline Thanks Meter: 0	i think cpu also controls signaling and too bad the t2x phones almost had the cpu glued all

03-03-2004, 23:52	#11 (permalink)
arness Crazy Poster Join Date: Mar 2004 Location: Romania Age: 49 Posts: 51 Member: 56692 Status: Offline Thanks Meter: 2	Maybe i`m wrong,but i know there are 2 different versions of boards on T20. One of them have a type of PWR AMP and a ICRF 11033,like T28,and the other one have another type of PWR AMP,and onether ICRF 3004CR1C,like 1018.Maybe this is the reason for incompatibility.

03-04-2004, 07:04	#12 (permalink)
L_DIM2003 Freak Poster Join Date: May 2003 Posts: 117 Member: 27990 Status: Offline Thanks Meter: 0	yes, there is two different boards for T20/T28 yesterday i had new problem with this is phone (T20) from this phone i can perfect make call with one operator (tele2), also this phone show perfect parametrs on both bands with gsm tester, but with other operator it can't find net - net on lcd full and drop down, and again... same time phone can find net, but without calling... i think problem in frequency generator or in sintezator . i think that there is same frequency offset in phone and for different operator this is parameter may be very critical.... for one operator this is offset is wide and phone perfect synchronization with BS, for other operator this is offset little - and fail to connect... ok, i try change RF, 13 MHz, PA, all cmd arround 13 MHz (varicaps, capacitors...), reflow AD/DA converter, rewrite eeprom (but i think that it not help ), also change sintezator D300... not help