Everybody can contribute here in this thread

[1amigo]

Simple TEST to know Problem is Hardware or Software ?

I have been hearing from lots of technicians that a simple resistance TEST between the 2 Battery Terminal Contact Points on the PCB (without the Battery) in Forward and Reverse directions helps know whether the problem is in Phone's Hardware or Software.
Let us decide here first what we are going to say FORWARD RESISTANCE and what we are going to call REVERSE RESISTANCE :

FORWARD RESISTANCE :Connect the Black Probe of the Digital multimeter to the +ve pin of the Battery Connector and to the -ve pin of the Battery Connector, connect the Red Probe of the DIGITAL METER.

REVERSE RESISTANCE : Now Connect the Red Probe of the Digital multimeter to the +ve pin of the Battery Connector and to the -ve pin of the Battery Connector, connect the Black Probe of the DIGITAL METER.

or in brief :
FORWARD= +VE(B) BLACK(M) & -VE(B) RED(M)
REVERSE = +VE(B) RED(M) & -VE(B) BLACK(M)

Fellow forum members, please post readings that you get in different Nokia models here. Don't forget to mention whether it is from a working phone or a non-working (DEAD or not switching ON) phone. If the phone is switching ON but is having a different problem, please mention the problem.

To maintain uniformity, please post as per example below :

NOKIA 3310 OK
FORWARD RESISTANCE ____OHMS
REVERSE RESISTANCE ____ OHMS

NOKIA 3315 NOT SWITCHING ON
FORWARD RESISTANCE ____OHMS
REVERSE RESISTANCE ____ OHMS

[sarojrkl]

Before posting any thing I would like say THANKS to U and appreciate your intention. You have alway came forward to help freshers.

REGARDS

[1amigo]

NOKIA 3310 OK
FORWARD 380 OHMS
REVERSE NO READING

ANALYSING FORWARD RESISTANCE READING :
Now here, I would like to say that the FORWARD READING in most OK phones will be between 300 to 700 ohms. However, this reading is mostly OK only.
(1) If it is lower than indicated in this range (lower than 300 ohms), there is a likeliness of a direct shorting in the circuit like a PA or any other component which is connected directly to the +ve Battery Line or even a shorting between the + & - tracks on the pcb anywhere because of bad soldering or solder getting spread or dropped inadvertantly.
(2) If the reading is ok - no specific inference can be drawn. However, it also somewhat indicates the possibility of a SOFTWARE PROBLEM.
(3) If the reading is more than 700 ohms, most likely causes can be either a broken +ve line track or an open coil on the +ve line.[/

ANALYSING REVERSE RESISTANCE READING :
(1) If this Reverse Resistance shows any ohms, it means that there is a leaky part in the hardware and so it is definitely a HARDWARE FAULT. If after rectifying this fault, the phone can still be not switched ON, you may need to rectify a possible SOFTWARE PROBLEM BY FLASHING IT ETC.
(2) The Reading 1 in the digital multimeter means no reading or infinite resistance. Infinite means very high resistance. Ideally this Infinite reading in REVERSE RESISTANCE test is ok. SO this again increases the possibilty of a SOFTWARE PROBLEM which was also indicated above in FORWARD RESISTANCE TEST.
(3) For Infinite reading in REVERSE RESISTANCE test, also you must check for an open track in the circuit. Correcting n open track should not make any difference in this reading.
(4) If the reading is within specified range or less than 300 or more than 700 ohms, there is also a possibility of a open or short in the secondary supply lines like Vbb,Vcore,Vcxo etc.
.

Comments please from everyone knowing about it or wanting to know !

[1amigo]

FORWARD READING in most OK phones will be between 300 to 700 ohms.

NOKIA 3120 FORWARD 330 REVERSE NIL
SE W550i FORWARD 440 REVERSE NIL
SAMSUNG E700 FORWARD 520 REVERSE NIL

[1amigo]

Originally Posted by sarojrkl

Before posting any thing I would like say THANKS to U and appreciate your intention. You have alway came forward to help freshers.

REGARDS

Hi Saroj !
I think you and me are the only 2 persons interested to discuss or post in this topic . So, now it is your turn to post . POST PLEASE ! Let us do the BEST we can !

[sarojrkl]

what more I can post I don't that much knowledge the way U R posting

[1amigo]

Originally Posted by sarojrkl

what more I can post I don't that much knowledge the way U R posting

Well, as you have understood what i wrote in my earlier post, just get any mobile (working or not-working) and measure the resistance between the 2 battery terminals as described - FORWARD & REVERSE. Write it down and post as in the example given by me here. It can be as below :

MAKE & MODEL NO. : ___________
STATUS : SWITCHING ON OK / NOT SWITCHING ON (DEAD)
FORWARD RESISTANCE : __________
REVERSE RESISTANCE : __________

THAT'S ALL, MY FRIEND.
TRY ONCE PLEASE.

[sarojrkl]

ok dear I will definitely post some observation tomorrow

[..:MumbaiGsm:..]

As i test at batt terminal is the status of handset i.e. its short , open , leakage or close(ok) circuit........
you will get reading over 1 Mega ohm...i.e.of ok handset...in reverse
wbr...

[.:KHALIFA:.]

???????????????????????????
wat this thread is about.....
discussing basic thing.....

[1amigo]

Originally Posted by ..:MumbaiGsm:..

As i test at batt terminal is the status of handset i.e. its short , open , leakage or close(ok) circuit........
you will get reading over 1 Mega ohm...i.e.of ok handset...in reverse
wbr...

Thanks MumbaiGsm
Please post some readings.
You also know how to make use of the readings, so please also post your comments on the readings obtained by you.
Best regards,

[r a nadeem]

dear lamigo,,
..:MumbaiGsm:.. is right
there are only three option
1- short ( as short )
2- open ( o, ohm)
3- normal (over 1 mega ohm)
one thing more the impendence of every moble is different ,after use and after hardware it has changed , u can test the same two mobile , check difference ,even the new two set ,
regards
rashid

[1amigo]

Originally Posted by r a nadeem

dear lamigo,,
..:MumbaiGsm:.. is right
there are only three option
1- short ( as short )
2- open ( o, ohm)
3- normal (over 1 mega ohm)
one thing more the impendence of every moble is different ,after use and after hardware it has changed , u can test the same two mobile , check difference ,even the new two set ,
regards
rashid

Thanks Mr.Rashid ! I have already thanked MumbaiGsm in the previous post.

As you may have observed in earlier posts, i have made a point to mention that all forward resistance readings falling in the 300-700 ohms range are more or less acceptable as OK readings. So we shouldn't be much worried if the forward readings from 2 handsets of the same model differ but still fall within this range. I understand this is what you are trying to say in the 2nd para of your post, right? You are very right about it. I endorse your valuable opinion.

My point was to guide Beginners to perform this TEST first and then judging from the results of this test, go to appropriate section, Hardware or Software for further investigation. I think you will agree to it.

[r a nadeem]

daer lamigo ,
thanks
its clear , its good for Beginners , to understanding hard or soft .
regards
rashid