2016年1月23日星期六
DEll D600 DC 1.05V 1.2V CIRCUIT FAST TEST WAY
Power management chip PU2 (MAX1715) output DC 1.05V voltage (VTT,test point 1), and DC 1.2V voltage (VCC_1_2_MCH, test point 2)....read more
2016年1月4日星期一
IBM THINKPAD T60 CLOCK CIRCUIT FAST TEST WAY
The clock circuit has a few power supply points, DC 3V voltage (VCC3B, test point 1 and 2)
L13 inductor, the resistance value about 0 ohm (test point 3)....read more
2015年12月27日星期日
IBM THINKPAD T60 DC CHARGING CIRCUIT FAST TEST WAY
Input DC 20V (VINT20, test point 1), after power management chip U42 (MAX8765) processing, output DC 12V voltage (CHARGER_OUT12, test point 2) to charge.
Complementary push-pull circuit Q4A Q4B, opposite phase PWM pulse signal to control mosfet (test point 3). Look at their waveform on the picture....read more
2015年12月19日星期六
IBM THINKPAD T60 DC 1.8V 0.9V CIRCUIT FAST TEST WAY
Input DC 20V (VINT20, test point 1), after power management chip U7 (MAX8632) processing, output DC 1.8V voltage (6A VCC1R8A, test point 2).
12-Pin of U7 (MAX8632) output DC 0.9V (VCC0R9B, test point 3).
Complementary push-pull circuit Q43 Q49, opposite phase PWM pulse signal to control mosfet (test point 4). Look at their waveform on the picture.....read more
2015年12月12日星期六
IBM THINKPAD T60 DC 1.5V 1.05V CIRCUIT FAST TEST WAY
Power management chip U29 (MAX1540ETJ) output DC 1.5V voltage (VCC1R5M,test point 1), and DC 1.05V voltage (VCC1R05B, test point 2).
Complementary push-pull circuit, opposite phase PWM pulse signal to control mosfet (test point 3). Look at their waveform on the picture.
U29 25-Pin control the G pole of Q14 Q90 upper mosfet, .... read more
2015年12月6日星期日
IBM THINKPAD T60 DC3V 5V CIRCUIT FAST TEST WAY
DC 20V ( test point 1) from DC input circuit, through power management chip U41 ( MAX1901), after processing, output DC 3V(test point 2) and DC 5V(test point 3) voltage.
Complementary push-pull circuit,...read more
2015年11月29日星期日
HP DM1 Laptop Doesn’t Boot, +VCC_CORE Voltage Missing
A HP laptop doesn’t boot, press power button, the current 0.35A stopped, According to experience, doubt power supply for cpu problem. So test +VCC_CORE (PL13), found +VCC_CORE voltage missing. Observe carefully, there is a small hole on the lower mosfet PQ26, it was damaged. Removed PQ26, test the resistance between PL13 inductor and gnd, the value is normal.
So, replace a new PQ26, connect power and boot again, the current still is 0.35A and stopped. Touch power ic RT8165B, very hot, suspected it was damaged, so replace a new RT8165B. Boot again, the current 0.20A stopped, +VCC_CORE voltage missing, yet. Take the schematic diagram, test +VIN, VCC, PVCC, EN, etc,...read more
2015年11月24日星期二
ASUS X43B Laptop Doesn’t Trigger, EC Doesn’t Reset
A asus x43b notebook, doesn’t boot, connect power adapter, the current 0.005A, standby 3V, 5V voltages are normal. When press the power button, the laptop doesn’t trigger, the current doesn’t change. So check EC’s working conditions first, the EC chip is KB930QF A1.
So check power, clk, reset singal, found 37-Pin ECRST# singal voltage is 0.24V only, it isn’t normal. +3VALW is normal, and R1605 plus C1533 are RC Time delay circuit, to 37-Pin reset EC. read more , By the way, In order to thank for every new and old customers and friends, offer 10% off from November 16th to November 30.
2015年11月23日星期一
2015年11月16日星期一
HP Compaq 511 Laptop Doesn’t Boot, Current 0.182A Fault
A HP Compaq 511 laptop, Press the power botton, the current 0.182A, then auto power off, doesn’t boot.
According to the current value, so doubt the power circuit problem, test +3VS, found the voltage is missing. +5VS voltage is normal.
So, check mosfet Q39 control G pole, the GATE_3S_R voltage is 0.24V only, it is not normal. Due to +5VS is normal, so GATE_3S is normal, just check GATE_3S_R circuit....read more
2015年11月13日星期五
HP 500 Laptop Clock Circuit Diagram And Failure Analysis
1, U28(ICS 954226) clock chip, if damaged, it will not respond when press the power button. Or auto reboot, or auto power off after led light. If 954226 pseudo soldering, will be able to boot sometimes, can not boot sometimes.
2, L31, L32 inductor, if damaged or pseudo soldering, it will not respond when press the power button, or auto power off.
3, X1 crystal oscillator, if damaged, will not able to boot.
4, C428, C431 resonant capacitor, if electric leakage or damaged,...read more
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