DV9500 blue LED ring of death ?

[BlueMidnight]

Re: DV9500 blue LED ring of death ?

Even I didn't see it at first. It's the point labeled "VAD-1" that connects both circuits. You can see it in small red text next to PD16.

Basically, the 2 transistors generate a square wave by turning on one at a time. But if one transistor goes bad and is stuck on, then it will cause a short circuit from 19V.. through PD16.. through one transistor.. through the other... and straight to ground.

It's possible just PQ62 went bad and only damaged itself and PD16. But it's a good idea to check all that stuff just in case. Don't want the new components to blow up too.

[bianchi77]

Re: DV9500 blue LED ring of death ?

Ok, so I need to buy diodes and transistor for fixing it....
The passive components I neen to check, where are they ?
near the burned PQ62 ?
So the transistor is working as an oscilator ...for switching PSU..

[bianchi77]

Re: DV9500 blue LED ring of death ?

Is this the burned transistor ?
http://www.aliexpress.com/item/Free-...6-af28a9ae48cd

[bianchi77]

Re: DV9500 blue LED ring of death ?

any idea on the board for making a wire to NBSWON1# so I can turn it on without the button ? because I need to connect with black membrane if I wanna use button....reduce the risk breaking the membrane being taken on and off repeatedly for a test..

[bianchi77]

Re: DV9500 blue LED ring of death ?

what's the different between PIMz2,115 and PIMZ2,125 ? or they're all the same ?

[bianchi77]

Re: DV9500 blue LED ring of death ?

I got someone fixing it :
--------------------------------------------------------
SUCCESS
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Hi, i have repaired my dv9500 following the process below... It took 15hours for me with motherboard schematics to find and fix the physical damages.

If the laptop doesn't switch ON but you have the right blue led adapter ON, it could be this:

===>> SHORTED CAPS which OFTEN destruct ICs or Diodes, so the current can't flow across the board...
If you experiment the "dv series dead power unit" issue follow this steps:
-take multi meter
-take self control
-take your laptop motherboard
-find FDS6679 (4413), FDS6900, AO4430 (4407) and MAXIM8724 data sheets

1-check these big orange or brown ceramic caps: PC32, PC33 ,PC 7, PC 9, PC 10
if one or plus are shorted or crisp, replace or just remove (risky but that's what i did)
2-check if FDS6679 (4413), FDS6900, AO4430 (4407) behave like healthy MOSFET Transistors if not REPLACE
3-check if PQ3(FDS6679) and PQ61 (AO4430) gates voltages are between 10-20V if not check all the ten diodes (PD xx) that are close around the 4-pin white power connector, if one or more is open in both ohmeter directions (for me, PD16, ref. ch501h-40 ) : REPLACE by another general purpose Diode or ch501h-40.

PS: at each step, check MAXIM8724 voltages, pin 1 must be 5V, and you have to read around 28-30V when mesuring at PR183 resistor (next to PQ61). Check often all mosfet gates voltages and try to run laptop at each step.

Regards

[bianchi77]

Re: DV9500 blue LED ring of death ?

PC32, PC33 ,PC 7, PC 9, PC 10, where are they on the board ??

[bianchi77]

Re: DV9500 blue LED ring of death ?

10U/25V/X6S/12 , what type of capacitor is it ?

[BlueMidnight]

Re: DV9500 blue LED ring of death ?

Yes, just the diodes and the transistor package are the only bad components so far. That link is the correct part. I think the -115 and -125 are the same. The -125 means it was bought from the factory as a 3000 piece reel.

I can't be sure where the components are, but they are probably nearby (on either the top or bottom of the board). All of them have labels, but sometimes the labels are written on another part of the board because there wasn't enough space.

That copied solution is from a different problem. His PD16 just went bad. Yours was fried because of a short circuit. But the part about checking around the input MOSFETs is good general advice.

For the 10U/25V/X6S/12 capacitor:

- 10U is the capacitance. 10uF in this case
- 25V means 25 volts obviously
- X6S is the temperature rating. Ceramic capacitors have these ratings, so that's what this must be.
- 12 is the first part of the size code. It must mean 1206 or 1210. Not sure which. But 1206 = 0.126mm x 0.063mm and 1210 = 0.126mm x 0.10mm


Electronics theory time...

That circuit uses the comparator PU11 and the capacitor PC198 to create a "relaxation oscillator". It uses the timing from the oscillator to trigger the bases of both transistors to either 19V or 0V. One transistor is an NPN and the other is a PNP. So when one is turned on, the other is turned off.

The only purpose of that whole circuit is to create AC voltage on capacitor PC195. That and the dual diode package PD20 form a "Cockcroft–Walton multiplier". It takes 19V and creates a much higher voltage from it (schematic says 28V). The 28V is used to turn on MOSFETs that are switching 19V. The gate voltage needs to be approximately 7V higher to turn them on.

[bianchi77]

Re: DV9500 blue LED ring of death ?

looks like PC6 is short I checked with continuity....beep loudly...

[bianchi77]

Re: DV9500 blue LED ring of death ?

most of 330uF are short...where are they in the schematic ?

[bianchi77]

Re: DV9500 blue LED ring of death ?

I've found 8 330uF tantalum caps short...why is that ? it's beep on continuity test...
can not it be identified by eyes isn't it...

like bulged on electrolityc ones....
but they look burned....can not see the label..

[BlueMidnight]

Re: DV9500 blue LED ring of death ?

Checking the input MOSFETs is fine advice. Checking all the capacitors is useless. Low-voltage/high-power rails will always look shorted. It's just Ohm's Law. You are measuring the resistance of capacitors on the the CPU/GPU/Chipset power rails. Those rails often have less than 1 ohm of resistance, and that is perfectly normal.

If you see anything burnt, take a picture.

[bianchi77]

Re: DV9500 blue LED ring of death ?

Checking the input MOSFETs is fine advice. Checking all the capacitors is useless. Low-voltage/high-power rails will always look shorted. It's just Ohm's Law. You are measuring the resistance of capacitors on the the CPU/GPU/Chipset power rails. Those rails often have less than 1 ohm of resistance, and that is perfectly normal.

If you see anything burnt, take a picture.

Oh, ok....

so they are fine....they don't look burned ....so the most possible is around PQ62...

[bianchi77]

Re: DV9500 blue LED ring of death ?

I've checked around PQ62....nothing short...

[bianchi77]

Re: DV9500 blue LED ring of death ?

Basically, the 2 transistors generate a square wave by turning on one at a time. But if one transistor goes bad and is stuck on, then it will cause a short circuit from 19V.. through PD16.. through one transistor.. through the other... and straight to ground.

does make sense to me....

[bianchi77]

Re: DV9500 blue LED ring of death ?

focus on PQ62 area :

[bianchi77]

Re: DV9500 blue LED ring of death ?

http://www.aliexpress.com/item/Free-...4-b71d635a2dc3How can I know TL331 is still good ?

[BlueMidnight]

Re: DV9500 blue LED ring of death ?

Yes, focus on that area. Check everything, but especially check PD21, PD22, and PC196.

There is no easy way to test the TL331. You can make sure there are no shorts between any of the pins, but that's all. It has to be tested in circuit. But if you have a current-controlled bench power supply, you can power the motherboard with that and not worry about shorts destroying things.

[bianchi77]

Re: DV9500 blue LED ring of death ?

I Hv only a standard charger...how can I limit it?