Tips For begginners

for cellphone repair!
a helpful guide for beginners:
thanks to www.gsmsandwich.com.ph

Flash ic
-auto reset (test w/ sim and without sim)
- unknown flash
- unable to write
-writable but unable to power on
- cant write imei (for internal eeprom only, if external then its eeprom chip)
-with power but can't read by mbus/flasher device
- read flash at first byte(address at 0x20001 then stop
- when writing always display "battery voltage is too low.
-cannot openline
SRAM
-No Power - Ram is Bad (Test with Banana Flasher)
- Read and Write Flash but unable to power on
- Auto off, when trying to power on again, unit can't power on.waiting for a few minutes to power it on.
- writng flash,but cant detect by flasher device,empty.
- in 3210 reading/writing stop.
Cobba(audio i.c.)
-no power if shorted (test it by hang method)
-contact service (serial/parallel)
-no signal
a.no rx (receive)
b.no tx (transmit)
c.intermittent signal
d.fluctuating signal
-signal stable but cant reach when trying to call, cant send sms, cant make a call
-no audio (earpiece/mouthpiece)
-garbled audio
-cant unlock (openline)
-sim card not accepted always appear
-auto reset (test with simcard only)

CCONT (power i.c.)
-No power
- No Signal
a.no rx
b.no tx
c.fluctuating
-insert sim card
-writing flashing error
-always hang (jammed)
- auto off (with sim and without sim)
-no display
-contact service
-no ui interface (blight,buzzer, vibra)
-with power but cant read by mbus flasher device
HAGAR (rf processor)
-No Power
-No Signal
a.No rx
b. no Tx
c.Fluctuating
d.Intermittent
-Auto off when receiving signal or after receiving signal
-Hang then off.
PA
-No transmit
-No Rx if overcurrent
-Auto off when making a call, or before entering menu
-no Power if shorted
-Short battery standby time (fast drain)
-Weak Transmit
Crystal osci (13/26 Mhz)
-No Power
-No signal
-Auto off
-Hang
Clock Crystal (real time clock)
-slow/too fast ringing tone
-slow/too fast clock timing
-intermittent signal
-no power if shorted
Antenna Switch
-No RX
-No TX
-Fluctuating Signal
-Intermittent Signal