SGH-D500 - keys 2,5,8,0,6 don't work!! - GSM-Forum

GSMBlade · 08-23-2005, 19:15

Hi!

Does anyone know what can be the problem!?

Keys 2,5,8,0 and 6 don't work, all other keys work perfectly! Sometimes they work perfectly and then again don't work...it drives me crazy!!

Phone wasn't water damaged but I cleaned PCB, removed C766-775 which are linked to the kepay, removed microphone, and again the same!!

Can flat cable be the problem!? Or any other idea!?

BR

07heaven · 08-23-2005, 19:20

Its usually the flat cable, but from my experience its been the upper slide keys that don't work, when the flat cable is at fault

but I guess while doing you other repairs you have disconnected it and reconnected it, if it is the flat cable, usually disconnecting and reconnecting sorts the problem out

07heaven · 08-23-2005, 19:21

Have you peeled back the white membrane and cleaned the contacts underneath the keypad?

GSMBlade · 08-23-2005, 20:05

Quote:

Originally Posted by 07heaven

Have you peeled back the white membrane and cleaned the contacts underneath the keypad?

Yes I cleaned and the PCB and membranes, and upper keys work perfect but I don't know if bad flat cable can make problem with lower side of the phone!!

Maybe will try to power on the phone without keyboard and membranes and try keys with screwdriver to see what will hapend!

BR

CPUKILLER · 08-23-2005, 20:32

Quote:

Originally Posted by GSMBlade

Yes I cleaned and the PCB and membranes, and upper keys work perfect but I don't know if bad flat cable can make problem with lower side of the phone!!

Maybe will try to power on the phone without keyboard and membranes and try keys with screwdriver to see what will hapend!

BR

check for corrosion on lower end of flex cable(the side towards main pcb)

tbash · 08-23-2005, 20:43

check the board for current reading on each of those keys it could be due to current failing to reach those keys,then ofcourse you'll have to trace the resistors necessary for that.

asa mobile · 08-24-2005, 09:12

i am sorry i can not help you

GSMBlade · 08-31-2005, 06:08

Quote:

Originally Posted by tbash

check the board for current reading on each of those keys it could be due to current failing to reach those keys,then ofcourse you'll have to trace the resistors necessary for that.

I find out what is problem, flat is OK, I tried this with open phone when I harder press the lower PCB keys work, when I release it a little bit they stop working!! So somewere is some line broken, or solder is broken!!

Is there any IC for keyboard or it goes directly to CPU!?!?

BR

adomshima · 09-01-2005, 17:16

Try re-soldering the cpu, i have try it on samsung A 200.

GSMBlade · 09-02-2005, 03:43

Quote:

Originally Posted by adomshima

Try re-soldering the cpu, i have try it on samsung A 200.

Yes I know that it will solve the problem, but CPU is glued!!!

BR

OLUJA · 09-02-2005, 13:24

You must to mesure with your instrument.
Keypad is broken because CPU is confused with the strange information,he think that is more keypad is pushed on.

GSMBlade · 09-02-2005, 16:07

Quote:

Originally Posted by OLUJA

You must to mesure with your instrument.
Keypad is broken because CPU is confused with the strange information,he think that is more keypad is pushed on.

You didn't read all my posts!! Phone is open, without membranes and make contact with screwdriver, and when I press harder PCB keys work, if I realese it a little bit they stop working!!

BR

themobileking · 09-02-2005, 17:28

By the info that you have given it seems that you have 1-2 tracks broken. Probably because the phone fell down or something like that .Please check all the main keypad tracks ....that should solve the problem.

Rgds

duskor · 09-04-2005, 00:02

Quote:

Originally Posted by GSMBlade

You didn't read all my posts!! Phone is open, without membranes and make contact with screwdriver, and when I press harder PCB keys work, if I realese it a little bit they stop working!!

BR

I have same problem like you, but you must to mesure with your instrument to fix this stupid problem.

B.R.
Dusko

roso · 09-05-2005, 12:52

Change The Flex Cable!!!!!

08-23-2005, 19:15	#1 (permalink)
GSMBlade No Life Poster Join Date: Mar 2001 Location: Croatia Age: 45 Posts: 723 Member: 3508 Status: Offline Thanks Meter: 71	SGH-D500 - keys 2,5,8,0,6 don't work!! Hi! Does anyone know what can be the problem!? Keys 2,5,8,0 and 6 don't work, all other keys work perfectly! Sometimes they work perfectly and then again don't work...it drives me crazy!! Phone wasn't water damaged but I cleaned PCB, removed C766-775 which are linked to the kepay, removed microphone, and again the same!! Can flat cable be the problem!? Or any other idea!? BR

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08-23-2005, 19:20	#2 (permalink)
07heaven No Life Poster Join Date: Mar 2004 Location: Midlands, UK Posts: 782 Member: 57937 Status: Offline Thanks Meter: 34	Its usually the flat cable, but from my experience its been the upper slide keys that don't work, when the flat cable is at fault but I guess while doing you other repairs you have disconnected it and reconnected it, if it is the flat cable, usually disconnecting and reconnecting sorts the problem out

08-23-2005, 19:21	#3 (permalink)
07heaven No Life Poster Join Date: Mar 2004 Location: Midlands, UK Posts: 782 Member: 57937 Status: Offline Thanks Meter: 34	Have you peeled back the white membrane and cleaned the contacts underneath the keypad?

08-23-2005, 20:43	#6 (permalink)
tbash Freak Poster Join Date: Jul 2004 Posts: 461 Member: 71751 Status: Offline Thanks Meter: 3	check the board for current reading on each of those keys it could be due to current failing to reach those keys,then ofcourse you'll have to trace the resistors necessary for that.

08-24-2005, 09:12	#7 (permalink)
asa mobile Junior Member Join Date: Aug 2004 Age: 42 Posts: 26 Member: 78934 Status: Offline Thanks Meter: 1	i am sorry i can not help you

09-01-2005, 17:16	#9 (permalink)
adomshima Freak Poster Join Date: Aug 2004 Age: 47 Posts: 149 Member: 78679 Status: Offline Thanks Meter: 3	Try re-soldering the cpu, i have try it on samsung A 200.

09-02-2005, 13:24	#11 (permalink)
OLUJA Insane Poster Join Date: Feb 2003 Location: Belgrade,Serbia Age: 55 Posts: 64 Member: 23157 Status: Offline Thanks Meter: 0	You must to mesure with your instrument. Keypad is broken because CPU is confused with the strange information,he think that is more keypad is pushed on.

09-02-2005, 17:28	#13 (permalink)
themobileking No Life Poster Join Date: Jun 2001 Location: Uranus Age: 53 Posts: 731 Member: 5072 Status: Offline Thanks Meter: 91	By the info that you have given it seems that you have 1-2 tracks broken. Probably because the phone fell down or something like that .Please check all the main keypad tracks ....that should solve the problem. Rgds

09-05-2005, 12:52	#15 (permalink)
roso Freak Poster Join Date: Jul 2005 Location: Italy Age: 42 Posts: 146 Member: 164613 Status: Offline Thanks Meter: 11	Change The Flex Cable!!!!!