VAR00 LA-9201P short to ground

[bjhawfam]

Re: VAR00 LA-9201P short to ground

106,,,, 3v

[bjhawfam]

Re: VAR00 LA-9201P short to ground

3v on both

[caspian]

Re: VAR00 LA-9201P short to ground

so it seems the cable to the power-button board is faulty.

[bjhawfam]

Re: VAR00 LA-9201P short to ground

thats amazing,,, as stated in my previous statements the cable was damaged,, this lead to shorts in the resistors in the power board... will order a new cable..

[caspian]

Re: VAR00 LA-9201P short to ground

check continuity or resistance from pin2 of D26 to KB9012.

[bjhawfam]

Re: VAR00 LA-9201P short to ground

shows no continuity from d26 to kb9012

[bjhawfam]

Re: VAR00 LA-9201P short to ground

bought new board and cable,, just wanted to report there's still no power,,, continuity from kb9012 to pin2 154.8... now there's no led's on either power board and 7 beeps from the speakers...

[caspian]

Re: VAR00 LA-9201P short to ground

check resistance from pin2 of D26 to KB9012 pin 106 and 114.

[bjhawfam]

Re: VAR00 LA-9201P short to ground

With the new cable and board,,,,,,,,O.L ON 114 and 0.L ON PIN 106,,, just bought this meter today, didn't trust the old multi.. pin 2 on D26 FLIPS OUT WHEN VOLTAGE IS TESTED starts low and climbs high over and over with a UEI DL49B meter, I get 0.143 volts on pin 2 with a cheap craftsman multimeter and 0.01 with an even cheaper meter a centech harbor frieght junk ... strange though, today when testing with power the 7 beeps are gone and the fan spins for 1 second not at normal speed just spins one full turn and stops... pins 1 and 3 are 3+ volts,,, d26 bad? now with the new meter I get 5 volts on 106 kb9012 and 3v on 114

[caspian]

Re: VAR00 LA-9201P short to ground

d26 seems ok.

[bjhawfam]

Re: VAR00 LA-9201P short to ground

okay was digging around and found pc114 coming off of pu100 gets extremely hot burned the finger tip...

[bjhawfam]

Re: VAR00 LA-9201P short to ground

I was trying to locate why there was so much change in voltage on that line and found that capacitor was burning up.. 3.3 volts to the cap, replaced just in case and still burns up..

[caspian]

Re: VAR00 LA-9201P short to ground

so this is another fault. the previous fault on the cable seems fixed.
now measure resistance on each side of PC114 and PR103 relative to ground.

[bjhawfam]

Re: VAR00 LA-9201P short to ground

pr103 is inconsistent starts low and climbs to 15.34 on one side of resistor the other side is all over the place...... pc114= 267.9 on one side of the cap and 000.2 on the other...

[caspian]

Re: VAR00 LA-9201P short to ground

pr103 and pc114 are connected on one side. so they must have the same resistance on that side.
anyway, if you measure stable 3.3v on +3VALWP and +3VLP and stable 5v on VL and +5VALWP, leave pu100 alone for now.

[caspian]

Re: VAR00 LA-9201P short to ground

now measure voltage on pins 84,89,95,100,101,121 of kb9012 after turning on.

[bjhawfam]

Re: VAR00 LA-9201P short to ground

I'm a little confused, wouldn't it be different readings from the cap to ground vs the resistor to ground. In the illustration if I check the resistance from both the same sides to ground 1 than I'm essentially checking the resistance of the rail/trace or path to the cap and resistor (would essentially be the same) . If I check resistance of the capacitor to ground its a different path/rail to ground than the resistor (illustration 2 and 3 ) therefore the resistance would be different correct? The reason I ask is if I ohm the resistor out and compare to like resistors it shows a bad resistor. The out voltage from the resistor is all over the place... Would like your thought on this.... I'll check the voltage of the pins on kb9012... Thanks again..

[bjhawfam]

Re: VAR00 LA-9201P short to ground

kb9012

pin 84=0
pin 89=0.03
pin 95=0
pin 100 = 0
pin 101=0.03
pin 121=0.03

[caspian]

Re: VAR00 LA-9201P short to ground

pr103 and pc114 must have the same resistance to GND on side 1. In addition, pr103 is a 0 Ohm resistor. So resistance to GND on side 1 and 2 should be the same too.
To bypass this problem of pu100, measure voltages +3VALWP and +3VLP and VL and +5VALWP and pin7 of pu100.

[caspian]

Re: VAR00 LA-9201P short to ground

kb9012

pin 84=0
pin 89=0.03
pin 95=0
pin 100 = 0
pin 101=0.03
pin 121=0.03

is there even a temporary 3v on these pins after pressing the power button?
if not, the laptop has problem in power rails.