Easy way to check LCD light fault in some bb5 phones

[MAGDY2]

hi

u can use this sequence steps 2 know what cause the lcd light

fault

Before we begin we should know that lcd leds need high voltag
(Usually 12~16 v)
but our source (battery voltage 3.7 v)

so we use Special electronic Components 2 have this high

voltag
needed 2 the leds of the lcd (usually dc-dc converters)

Now, let's start

Suppose that we have a bb5 phone with lcd light fault
(let us say e70)
i use e70 to show u the easy way 2 find lcd light circuit
Because this device is not common and We usually dont know
where is the lcd light circuit or driver



step 1

open e70 shematic and Search 4 pwm (see pic)



Note 1
pwm is Pulse-width modulation
(it is the controler in dc-dc converters voltag switching)
pwm keep voltage constant




from the first search Result we found our controler(pwm)
and our lcd light driver (n2301) see pic



driver location in the mainbord



the lcd light driver have 8 pins
only 4 of them needed 4 tracking lcd light pb(often)
see pic



step 2
check the vout pin voltage in the Component that conected 2

this pin (in our case Capacitor c2315)



also this voltag should be in lcd conector (pin 20 in e70)
there is also low voltage (often 0.5 v or lower)
this low vol is fb feedback
(in pin 21 lcd conectore and in r2304)

if the vout vol is missing we should move to next step

step 3
check the en pin (enable)



this pin give the led driver the authorization to start
voltage switching
sometimes there is test point(in our case j2309)
we can check en vol(usualy 1.8v when light active)
in our case the test point is near led driver(see pic)

if the en voltage is not ok
we have 2 change the Component conected to en pin
in our case thavo

if the en voltage is ok we move 2 next step

step 4
check vdd pin (some times it called vin pin)


this pin supply the lcd driver with vbat voltage
(in our case check c2314)

if every thing is ok move 2 next step

step 5
check ind pin (Induction)


this pin supply the lcd driver with vbat voltage
Through coil (in our case l2304)
we check the coil 2 test this pin

many Other bb5 phones can be checked in Similar way
such as:
3250-3109-3110-5200-5300-5700-6125-6131-6133-6136-6151-6233-

6270-6280
6290-6500-6555-6630-6680-6681-7370-7390-7500-e50-e60-e61-e65-

e70-n70-n71
n72-n73-n76-n77-n80-n81-n82-n91-n93-n95-n770

this is only one way but it is the most common way

sorry 4 bad eng

hope it is clear and Useful


B.R

MAGDY2

[EPmobile]

thank you for solution

[dfs3ds]

THank you for your information vey useful.

in case of me, n70 j2309 has not any vol even after changing TAhvo. whats the problem?

[MAGDY2]

Originally Posted by dfs3ds

THank you for your information vey useful.

in case of me, n70 j2309 has not any vol even after changing TAhvo. whats the problem?

do this jumber and post the result

[dfs3ds]

Thank you master, it worked. I had not any output in c2315, and now I have 0.33 v. but I am wonder why my main problem yet exist;
when the phone is switched on by power supply, the current starts from 32 goes to 25 and stops there for about 4 second and then become off (0.00). no light both in Lcd and Keypad. Please Help if you know the solution. the phone problem was white screen and I repaired it by changing display filters and making jumper. this solution worked pretty nice just for about 4 hours and now I have this problem: no light, hang and off.

[MAGDY2]

Originally Posted by dfs3ds

Thank you master, it worked. I had not any output in c2315, and now I have 0.33 v. but I am wonder why my main problem yet exist;
when the phone is switched on by power supply, the current starts from 32 goes to 25 and stops there for about 4 second and then become off (0.00). no light both in Lcd and Keypad. Please Help if you know the solution. the phone problem was white screen and I repaired it by changing display filters and making jumper. this solution worked pretty nice just for about 4 hours and now I have this problem: no light, hang and off.

ok this jumber was only 2 be sure that ur light driver is ok
remove jumer
the phone problem was white screen what kind of white screen
some times phone work well without sim card
with sim card it work and after a time its hange or go into white screen
this fault is smps or omap fault (specialy if the phone fall or water dameg)
tell me about phone history

[gsmsikar]

thanks sir ,

this is good topic for mobile technicians ..

[shahidsattar]

great work dear. u have done a great job. keep iy up

[dfs3ds]

Dear master,
the phone got white screen while his owner was working with it. when he brought it to me, the phone display had white screen, but yet you could hear the sound of keypad beep while pressing them, you even could hear the ring sound when there was a call.
by changing display filters and making this jumper (( http://www.4shared.com/file/15147214...ite__hang.html )), the phone recovered and the problem solved. there was no more white screen and the display was ok, but the display was a bit blinking.
the phone was ok just for about 4 hours and then the phone hanged while the phone was on, after restarting the phone it became ok but after 1 min it hanged. after restarting the phone the phone did not boot up, it was just hanged white screen. and at this moment the problem is blank display ( no light at all, both in key pad and screen) , hang ( you cannot see the nokia logo), and off ( when you power on, the current starts from 32 comes to 25 and then it becomes 0.00 (off).

Your have done a great work by discribing the scematics, Please continue.

[MAGDY2]

did u try full flash
do check with jaf and post
if the check is ok try full flash and post log
the custmer said what they always said nothing hapen
what do you see in phones board

[dfs3ds]

here it is.

check with jaf:




APE Boot Data:
Asic ID: 17100701
Asic Mode ID: 00
Asic Public ID: 5662AB7AFC58A325A9D21F35E39ADA40C131B62A
HASH: 2C05369F57CC3C4CF9E783E83D9B512B00000000
ROM ID: AB5E4ADB27A06946

CMT Boot Data:
Asic ID: 000000010000022600010006000C192101002200
Asic Mode ID: 00
Asic EM ID: 00000352
Asic Public ID: 1DD000044DBD58518F444BACFCE2FFD0CD5C62BD
HASH: E9EFF4BFAA5393217CA6B17755FC3E1400000000
ROM ID: F28A211FCEA7B19D
Error finding cmt boot file...



I think it is not ok to flash it. while erroring :

Setting FLASH MODE
Error finding cmt boot file...
Failed to backup CRT...

ufs check:
1ST BOOT : C0,0C [Rm-84] [2.0.8.0]
OMAP ID : 17100701
OMAP MODE : 00
OMAP PBID : 5662AB7AFC58A325A9D21F35E39ADA40C131B62A
OMAP HASH : 2C05369F57CC3C4CF9E783E83D9B512B
OMAP ROID : AB5E4ADB27A06946
RAPx ID : 000000010000022600010006000C192101002200
EM 1 ID : 00000232
EM 2 ID : 00000352
RAPx PBID : 1DD000044DBD58518F444BACFCE2FFD0CD5C62BD
RAPx MODE : 00
RAPx HASH : E9EFF4BFAA5393217CA6B17755FC3E14
RAPx ROID : F28A211FCEA7B19D
CMT 1ST Boot OK
CMT 2ND Bt: RAP3Gv2_2nd.fg, Ver: 1.21.0
00000000: 02 00 00 00 00 F1 72 ......r
ERR: CMT 2ND Boot CMT 2ND CERT Mismatch
Rebooting Mobile

[MAGDY2]

Originally Posted by dfs3ds

error finding cmt boot file...



Error finding cmt boot file...

Err: Cmt 2nd boot cmt 2nd cert mismatch

is the flash ic protected

this is flash ic pb

maybe it is flash ic voltage supply(retu)

ur fault is clear cmt fault means flash ic

some times it is retu or rap3g

but i think it is flash ic (most of the time)

maybe overheating led driver dameg protected cmt flash near it

b.r

[dfs3ds]

Thank you for your kind Help.
nice Thread.

[billal1050]

Thanks Bro Nice Post ....................

[abheejeet]

good post sluat for u friend