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danverdejo
12-08-2002, 12:10 AM
Hi! guys,

What really the main problem of no signal or low signal, to 6210 and 8210 etc.. what is the right procedures to find out which part or parts are defective.

can anyone give me an practical advice to find out what really the right ways to find the problem.

thanks
dan,

glicos
22-08-2002, 01:58 PM
unzipped below file then read the contents..i hope this will help..

mehdi
22-08-2002, 02:16 PM
hi try to remove PA then clean pcb from water
and resolder it !
or change PA

danverdejo
24-08-2002, 12:08 AM
thanks for the reply,

but changing parts like PA or deplexer (ant switch) cobba, haggar or ccont is easy to say that they are defective neither to change, but I like to known if how you can check the part or parts that really defective, I search on the net about signal problem but all the same change PA, deplexer, reheat the cobba haggar or ccont.

but in service manual you have to use Wintesla, to know if really what the problem of your mobile (signal TX,RX) but where I can fine a Wintesla that works properly, most of them are not usuable. (please dont advice me to buy from Nokia company).

Anyone try to use Wintesla in practical application that really can solve the signal problem, before replacing parts.

thanks,
danverdejo

glicos
24-08-2002, 05:27 AM
Originally posted by danverdejo
thanks for the reply,

but changing parts like PA or deplexer (ant switch) cobba, haggar or ccont is easy to say that they are defective neither to change, but I like to known if how you can check the part or parts that really defective, I search on the net about signal problem but all the same change PA, deplexer, reheat the cobba haggar or ccont.

but in service manual you have to use Wintesla, to know if really what the problem of your mobile (signal TX,RX) but where I can fine a Wintesla that works properly, most of them are not usuable. (please dont advice me to buy from Nokia company).

Anyone try to use Wintesla in practical application that really can solve the signal problem, before replacing parts.

thanks,
danverdejo


danverdejo

what youre suggesting here is actual troubleshooting to locate exact problem before replacing a part. This is a good approach in dealing with defective cellphones but the problem is the availability of necessary test equipment to do the job, which is sad to say...VERY EXPENSIVE for practical approach (unless your planning to put up a certified service center). It is much more practical to replace the parts directly than to buy those expensive equipment.
Service manual offers many data (test points, signal, voltage levels etc) for a consice troubleshooting analysis but requires very expensive equipment. Some of Wintesla's capability can't be use unless you have the equipment to do the job.

For now, i'm using the component test mode of Fluke 867B to find bad component signiture (in-circuit) and compare it with a known good working cellphone. I have seen one such function on some low-cost oscilloscope here in the philippines (alexan has one). For my experience, this approach is much better coz you dont have to power up the phone when troubleshooting. The only drawback with this approach is you must have the same model of cellphone to compare with.

danverdejo
25-08-2002, 11:03 PM
thanks to your reply Glicos,

I agree with you, but as for your experience, can you tell me how to start troubleshooting no signal, for example 6210.

I have a Simpson Digital / analog multimeter, Textronix 100mhz osilloscope, Leader AF RF signal generetor,sweepmarker gen., Leader 1GHZ digital frequency counter, 850 smd rework and reballing kit. most of them I used for my partime job as Electronics tech. and i want to start to repair mobiles.

now.. what's the first step..

one more thing mr glicos, you mentioned that "For my experience, this approach is much better coz you dont have to power up the phone when troubleshooting" to test, I think this is only posible for resistance or continuity checking.

danverdejo,

glicos
28-08-2002, 02:18 AM
Originally posted by danverdejo
thanks to your reply Glicos,

I agree with you, but as for your experience, can you tell me how to start troubleshooting no signal, for example 6210.

I have a Simpson Digital / analog multimeter, Textronix 100mhz osilloscope, Leader AF RF signal generetor,sweepmarker gen., Leader 1GHZ digital frequency counter, 850 smd rework and reballing kit. most of them I used for my partime job as Electronics tech. and i want to start to repair mobiles.

now.. what's the first step..

one more thing mr glicos, you mentioned that "For my experience, this approach is much better coz you dont have to power up the phone when troubleshooting" to test, I think this is only posible for resistance or continuity checking.

danverdejo,

Then read the service manual of a particular phone. You can find a lot of information there. Youll only need a test jig to hook up the phone for dynamic testing. There's a link somewhere in this section where you can download service manual for a particular phone.

About the curve tracing, resistance and continuity are not the only one checked by this method. It also check the dynamic characteristics of the component. Different component produce a different curve, including same component values manufactured by different manufacturer. Take note curve tracing used AC signal with varying frequency and amplitude, unlike resistance and continuity that used a DC signal.

yours truly,
Mr. Glicos :D

danverdejo
28-08-2002, 09:14 PM
thanks Mr.Glicos,

you are right, I just look for service manual in everything is there,
but I'am asking for some practical advice to troubleshoot signal problem. most of them are always telling directly to change (PA,ant switch,cobba,haggar) and that's it everything solve the problem.

mr glicos, I'am asking for your advice on how to check PA or Antenna switch and parctical trobleshooting without using Spectrum Analyzer, or it is posible to just feed signal to antenna terminal by using RF signal generator and check the out from out PCN and out GSM (of course with power) check by oscilloscope all outputs signal comming from RF generator.

sorry for asking to many questions..

thanks,
danverdejo

downunder
28-08-2002, 11:49 PM
without a spectrum you will struggle to measure output of pa or antenna switch, genarally though if the pa is faulty you should see higher current drain at power levels 5, 6, 7. if the antenna switch is faulty you usually find at least a 6 or 7 db loss from
input to output.

danverdejo
29-08-2002, 09:30 PM
thanks to downunder for your reply..

danverdejo

mimmy228
03-09-2002, 12:11 PM
I've read all the post but i didn't get the direct answer,
the question is ,my 8250 has poor signal or no signal at certain time on "GSM" but has good signal on "PCN".

Please , give me more precised part that need to be changed,
with the experienced people like U guyss, i think there should'nt be any problems.

Thanx.

markchee
03-09-2002, 08:41 PM
Helow,mimmy228


Try to change the 'Antt Switch'.Thatis why we name it switch.

Regads
markswitch

mimmy228
04-09-2002, 12:53 AM
Originally posted by markchee
Helow,mimmy228


Try to change the 'Antt Switch'.Thatis why we name it switch.

Regads
markswitch




THANXXXXXX, mark.

I'll try it out!