BGA Repair Guide

BGA Repair Guide

Due to the special nature of BGA package IC, which has certain requirements and welding techniques and

welding effects (short circuit, false welding or good) direct observation with the naked eye is not easy,

in order to improve efficiency, reduce costs and ensure product quality formulated the Guiding

maintenance operations.

Guidelines for the implementation of this operation maintenance personnel must have the following

qualities: understand the basic working principle of mobile phones, mobile phones know each part of

the circuit theory and signal flow, have a certain electronic technology and welding techniques, proper

use of basic service tools and equipment.

Now each of the steps of the flowchart will be described as follows:
Step 1. First verify the veracity of the fault; failure to observe the phenomenon of the failure of

maintenance and have a general direction.

Step 2. visual inspection methods that may cause the failure of the relevant circuit components to check

to see if there are false welding, short circuit, leakage of the wrong material, the direction is not correct

and signs of damage and the like.

Step 3. The peripheral circuits BGA soldering station found a problem with the proceeds to Step 6. repair

not good to go to step 4. OK then go to step 10.

Step 4. visual inspection can not resolve the problem by using various detection tools, equipment and

other means of causing the failure to check the relevant circuit (such as measuring resistance, voltage,

current, waveform, etc.), combined with the principle of signal flow prior without moving BGA condition

of peripheral circuits BGA were excluded (eg RF power supply part of the problem to be investigated

further by measuring the BGA external I / Q signal, the frequency synthesizer control signal band

transceiver switching control signal TX oN signal, power, level control signals point to determine whether

there are problems BGA; control logic portion may be excluded or input and output pin power supply,

13M circuit and the functional circuit and other related circuits).

 Step 5. The exclusion of the peripheral circuit of BGA only after checking BGA, BGA determine the fault

is false welding, or damage caused by a short circuit.

Step 6. is the process of checking out of the question for repair.

Step 7. For judgment BGA short circuit or damage to the BGA removed for inspection reasons and

BGA ball with a dedicated test fixture for testing BGA damage.

Step 8. For false judgment BGA solder can be applied by hot blow-clean flux method of treating, not

then go to step 7. Perform demolition BGA Inspection.

Step 9. Remove detection for BGA re-installed using the good, the bad and replace materials; such as

reloading or unresolved issues back to step 4. reinstall OK, go to step 10.

Step 10. Go repaired machine production line for production.