6020 intermittent signal - dropping signal

History:  This unit was brought to me by my customer.

Diagnostic:

1.  After I disassemble the unit I found out the board is already repaired.  The PCB board is full of flux and messy.  Signal is dropping after I power on the unit.  This symptons is usually a problem in the TX circuit.  You can verify it by doing a manual search in the settings of your cellphone.  If you could search all the service provider then TX is the problem.

2.  I usually replace P.A. in this common problem.

Solution:  Replace P.A.  After replacing the amplifier the unit is working again.  see the picture below.

Just replace P.A. part number N7700.  Problem will be solved.

Back to:  Cellphone repair problem and solutions

1600 no LCD light solution

Problem:  1600 no light on display causing very dim LCD.

Solution:

Check for Vbat if there is a supply voltage (see the image below).  If there is no voltage make a jumper connection from Vbat to the inductor from the picture provided below.

There is another solution but in this case this is the solution.  Just in case there is a supply voltage and still there is no light in the LCD you may replace N2400 LCD driver IC.

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3230 No power and local mode but finish flashing using any gadget

Here is the one of the solution for cellphone that can be full flash but still will not power on or local mode.  In this tutorial I encounter it in one my repair nokia 3230.

History: It was repaired from another cellphone repair shop. They only replace the battery terminal. it worked for an hour then suddenly it wont power anymore.

Procedure:

1. To be sure that the software is good I reprogram it using higher version of firmware available.

2. After flashing no local mode and the phone is still no power.

3. Carefully inspecting the terminal and using the multimeter I found out that BSI has no continuity. Using jumper wire I connect the BSI using the schematic diagram at jumper 136.

4. Now the phone has power then using software again full factory then mobile is perfectly working again.

see the missing connection below:

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Nokia 3110c signal problem solution

There are many ways to solve signal problem in 3110c and this solution is one of the different solution to solve it!

To solve any signal problem in cell phone you need to determine first which part of the signal circuit is the problem.  Signal is divided into two circuit the Receiver or Rx circuit and Transmitter of the Tx circuit.

To determine if Rx or Tx problem use the manual search from the cellphone. You can find it at the settings.
If the phone can search all the service provider you have a good Rx circuit and bad Tx or If there were no signal found you have a bad Rx and possible good Tx.

In this case I could search for all of the service provider.

What I did was I replaced the capacitor from the picture I provided below:

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R225M T-Mobile unlocked by ufs

Samsung R225m locked to T-Mobile openline by my favorite power flasher box.

This phone was locked to T-mobile service provider only. If you have a Ust-Pro Gadget you won't be able to unlock the phone. I tried it several times but no luck.

Going back to my favorite flasher / unlocker unlocking was successful.

See my screenshot below:

Back to: Cell phone repair