LAPTOP REPAIR

  HP Compaq CQ40 laptop always  supply (3v-5v always) System If CQ40 laptop has good B+ main supply which necessary for system to turn on always supplies( 3VL and 5VL ). Always supply is to maintain system in ready state before pressing power button.TPS51125 is used in CQ40 for standby supply regulation. Note: Check B+ and Charging supply Articles for Details LDO or Standby section In Compaq CQ40 B+(18.5v) supply apply to pin16 of tps51125 It receive power supply for ic’s LDO (3.3v and 5v) Read more...

HP CQ40 Battery Charging Discription    HP CQ40 Charging Description Laptop battery is charged by external power. Which is uselly output dc voltage and provide power to system and charge battery simultaneously. When battery fully charged continoue supply to system through adaptor and cut battery charging .Every laptop has his own type of configured charging circuit. Charging process is manage by multi controllers like: • Charging ic • KBC I/O controller (for battery temperature, level, enable and adaptor detection) • Battery internal rom chip or external rom u28 (battery must be connected) First of all system supply B+(main supply source) is available for system startup Note: for more on B+ Supply Read Article  http://www.laptoprefix.com/viewforum.php?f=13 Read more...

HP CQ40 Main Power Supply B+ Description Hp CQ40 Supply With Hp Adaptor Introduction Cq40 is commonly use and very often find laptop and its circuit is very basic similarities with other hp models. So I explained it Charging section First. it is charging with hp’s 3 pin adaptor architecture. It is very often in others companies like dell, lenovo etc. it protect system with external over voltage and surge. When there is damage in circuit it stop output from adaptor. ID signal is use to operate charging Enable function. Read more...

Main Changes in CQ42 is as Follows: Given Replacement is not Guaranty for hardware safety or damages, Do it at your own risk.  (yashan Agrawal) 1.         Clocks provides VGA block operations (page 3) part of the U16B clock section .  When amd vga chip is used Rb (R350) = 0 ohm, Rc(R351) = 0 ohm, Ra = NA (not used) config is used.   UMA is used  Ra = 0 ohm, Rc = NA, Rb = NA.              DIS UMA Ra(R343) NA 0 ohm Rb(R350) 0 ohm NA Rc(R351) 0 ohm NA            Remove Rc = 0 ohm (R351) and Rb = 0 ohm (R350) Add Ra = 0 ohm (Dual resistor Ra = 0 ohm) (R343) located near the coil 2 PL3 and PL4 cpu resources.            for More Visit http://www.laptoprefix.com/viewforum.php?f=25