GH688,GA628, Standard Electrical Repairs
4/00021-2/FEA 209 544/1.G 26 (112)
* Measure the resistance from X602 pad 5 to ground (>100 kohms).
* If it’s too low, make sure there’s no dirt or oxide between the compo-
nents in the marked area (fig. 4.5). Clean thoroughly and measure again.
Fig. 4.5
* If the resistance still is too low, remove R601 (class A, fig. 4.4).
* If the resistance increased, replace D600 (class B, fig. 4.2) and
mount a new R601.
* If the resistance didn’t increase when removing R601 or it
didn’t help by replacing D600, send the phone to the next level.
* Measure the resistance from X602 pad 3 to ground (>100 kohms).
* If it’s too low, make sure there’s no dirt or oxide between the compo-
nents in the marked area (fig. 4.5). Clean thoroughly and measure again.
* If the resistance still is too low, remove R605 (class A, fig. 4.4) and
measure again.
* If the resistance increased, replace D600 (class B, fig. 4.2) and
mount a new R605.
* If the resistance didn’t increase when removing R605 or it
didn’t help by replacing D600, send the phone to the next level.
If all the above measured resistances are correct, but some of the voltages at
R601 or R605 are low it’s either caused by a slight short circuit due to dirt at
the marked area in fig. 4.5, broken F603 or broken F604.
• If the voltages at R601 and R605 are correct, connect a handsfree to the system
connector.
• Measure the voltages at both sides of R601 (~0V, fig. 4.4) and at D600 pin 70
(~0V, fig. 4.2).
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