Hp Probook 455 G3 DAX73AMB6E1 blinking charge light, not turning on

[rccrasher65]

Re: Hp Probook 455 G3 DAX73AMB6E1 blinking charge light, not turning on

[QUOTE=rccrasher65;874254]I'll retest those components, plus the ones I didn't get to. My parts are going to be in today, so I should be able to power up board. thanks again. I did go over board there are no obvious signs of damage present. checked it a few times befor I purchased a replacement, that you helped get back in working order. Thanks again for that.[/QUOTE My parts are in, I can power the board now. just need to know what to test.

[BlueMidnight]

Re: Hp Probook 455 G3 DAX73AMB6E1 blinking charge light, not turning on

First, finish measuring PQ5, PQ6, PL12, and PL15 in the manner described previously.

Since you have already seen what this board does when powered, and nothing burns down, you can also go ahead and measure the voltage on those same 4 components. Just use the multimeter on the regular voltage setting.

In general, you should have the heatsink and fan attached when powering the board, just in case the CPU is getting power (though it very well may not be).

For PQ5 and PQ6: Measure voltage on source, drain, and gate. It makes no difference which source or drain pin you are touching. All the source pins should measure the same and all drain pins should measure the same. Alternatively, you can just measure all 8 pins individually, and I'll worry about which pin does what.

For PL12 and PL15: Measure the voltage on either pin. It doesn't matter which. They should be the same.

Also, it's helpful to check for hot components. There are no high voltages anywhere on the motherboard, so just use your (clean and dry) fingers. There should be no localized hot spots at all (other than the CPU, if powered). If you locate any, that can indicate a short, and that the excess current is traveling through that hot component.

[rccrasher65]

Re: Hp Probook 455 G3 DAX73AMB6E1 blinking charge light, not turning on

PR103- red on ground
0.377V BLK on ground OL Re check of PL15-64.5K ohms, 0.344V PL12-0.4 ohms, 0.000V, this one testing still bad. PQ-5 red on source, Blk on drain-0.477V Blk on source,Red on drain-OL OL- gate- drain OL-gate- source. PQ9- red on source, blk on drain- 0.539V blk on source, red on drain-OL OL- gate-drain OL gate- source I do not know how to test.PL6 and PL1

[BlueMidnight]

Re: Hp Probook 455 G3 DAX73AMB6E1 blinking charge light, not turning on

PL6 and PL1 work just like the other "PLxx" components. Simply measure resistance from either side of the component to ground while the board is unplugged. It shouldn't make any difference to the readings you get whether you measure from one side of the component or from the other.

It appears you have a short on the +3VPCU power rail (of which PL12 is a part). There are many possible culprits on that rail. Things get more hands-on from this point..

What soldering equipment do you have? Soldering iron? Hot air station? Copper desoldering braid? Flux?

Do you by any chance happen to have a bench power supply on which you can control and limit the volts and amps?

[rccrasher65]

Re: Hp Probook 455 G3 DAX73AMB6E1 blinking charge light, not turning on

PL6-22.43K ohms PL1-1.667K ohms When you say check with regular voltage, you do mean DC correct. I have all the equipment necessary for the repair. I have hot air station, soldering iron , Re-ball station, flux, solder, wick ect. Will it be safe to power up board without the heatsink, I don't want to break down my computer if I don't have too. I purchased a power jack and fan, no switch. Would it be safe to do if I do measurements quickly and shut down power as fast as I can. I don't have a bench top power supply, I was thinking on getting one. off ebay, they are pretty cheap, as I only tinker, with electronics as a hobby. I have repaired about 15 plasma, and Lcd, led tv's over the last few yrs. Soldering skills are excellent. Just need to be told what to do.

[brew99]

Re: Hp Probook 455 G3 DAX73AMB6E1 blinking charge light, not turning on

I'd suggest getting yourself a small DC power supply that you can limit the current on. It can be very helpful in locating shorted components, as well as powering various things when you don't have the proper power jack. Look on flea-bay for something like 30V, 5A that you can put into constant current mode. I recently bought one for about $50 CDN

[rccrasher65]

Re: Hp Probook 455 G3 DAX73AMB6E1 blinking charge light, not turning on

Thanks for the reply, looking for one as we speak. Thanks again.

[rccrasher65]

Re: Hp Probook 455 G3 DAX73AMB6E1 blinking charge light, not turning on

PL6 and PL1 work just like the other "PLxx" components. Simply measure resistance from either side of the component to ground while the board is unplugged. It shouldn't make any difference to the readings you get whether you measure from one side of the component or from the other.

It appears you have a short on the +3VPCU power rail (of which PL12 is a part). There are many possible culprits on that rail. Things get more hands-on from this point..

What soldering equipment do you have? Soldering iron? Hot air station? Copper desoldering braid? Flux?

Do you by any chance happen to have a bench power supply on which you can control and limit the volts and amps?

I have some voltage measurements that you requested. PL15-5.06V PL12-0.000V PQ5 Pin 1-19.73V pin 2-19.73V pin3-19.73V pin4-24.62V pin5-19.74V pin6-19.74V pin7-19.74 Pin8-19.74V PQ9- Pin1-19.74V Pin2-19.74V Pin3-19.73V Pin4-24.32V Pin5-19.74V Pin6-19.73V Pin7-19.74V Pin8-19.73V

[BlueMidnight]

Re: Hp Probook 455 G3 DAX73AMB6E1 blinking charge light, not turning on

Yes, by "regular voltage setting" I meant the DC volts setting (as opposed to the diode mode setting, which also shows reading in volts).

All those measurements look good as well.. except PL12 of course. That's supposed to be the 3.3V power rail. There's no question there is a problem there.

Those bench power supplies do come in handy. We can wait for you to get one if you'd like. The next step, if you don't have a bench power supply or no component gets hot while using the bench power supply, is to start removing components to see if the short goes away. And there are quite a few components to check.

[rccrasher65]

Re: Hp Probook 455 G3 DAX73AMB6E1 blinking charge light, not turning on

I can pick one up if you think that will make things easier, probably going to take a week or so. The cost isn't that bad. I 'll look for one tonight.

[BlueMidnight]

Re: Hp Probook 455 G3 DAX73AMB6E1 blinking charge light, not turning on

You could remove PL12 and then measure resistance to ground on both pads. If the short is on the controller chip (PU11) side, then that's your main suspect. But if the short is on the other side you still have many things left to test.

But, PL12 is in a pretty bad spot, being right between the plastic battery holder and a capacitor, and having so much mass itself. So precautions would need to be taken. If you're getting a power supply anyway, might as well wait.

[rccrasher65]

Re: Hp Probook 455 G3 DAX73AMB6E1 blinking charge light, not turning on

Ordered DC power supply this morning, should be here on or around the 25th.Can you show me what the suspected component looks like? What would be the best way to remove PL12, I do have Kapton tape also, and I can make foil shields to protect surrounding components. I can also use 2 soldering irons to remove PL12. What do you think?

[BlueMidnight]

Re: Hp Probook 455 G3 DAX73AMB6E1 blinking charge light, not turning on

If you are referring to PU11, it is the black square component right above PL12 in picture #2. But that's just one of many possibilities.

Generally, I use Kapton tape to protect the nearby components. And then, when using hot air, I also ball up some foil and encase capacitors in it to absorb some of the heat. That's even more important for electrolytics. And that's about as far as I've ever needed to go with my precautions in practice.

But if you can successfully use double irons on PL12, then that is the most gentle way of doing it.

You could just wait too. Even if by chance PU11 were the culprit, it would still be instructive to practice the technique with your new power supply.

[rccrasher65]

Re: Hp Probook 455 G3 DAX73AMB6E1 blinking charge light, not turning on

Well, I think I'll just wait for the power supply. Can anything around that area be tested, that is PL12. I want to learn how to use that supply to find bad components. Are these components easy to source? I've used Mouser, Digi Key for the tv repairs. have a good evening and Thank you again!

[BlueMidnight]

Re: Hp Probook 455 G3 DAX73AMB6E1 blinking charge light, not turning on

Capacitors, resistors, and such can be readily found at any distributor. But for the ICs, sometimes you have to head to ebay or aliexpress, or maybe to some other site that specializes in those sorts of things. But they usually aren't hard to find. Usually.

[rccrasher65]

Re: Hp Probook 455 G3 DAX73AMB6E1 blinking charge light, not turning on

Capacitors, resistors, and such can be readily found at any distributor. But for the ICs, sometimes you have to head to ebay or aliexpress, or maybe to some other site that specializes in those sorts of things. But they usually aren't hard to find. Usually.

Is PL12 going to have to be removed in order to use power supply? If so I will remove, and do test you suggested.

[BlueMidnight]

Re: Hp Probook 455 G3 DAX73AMB6E1 blinking charge light, not turning on

The easiest place to attach a wire for the power supply will be one of the leads of PL12. But if PL12 were removed, you could attach a wire to one of its pads instead (whichever side still has the short). No big difference either way.

[rccrasher65]

Re: Hp Probook 455 G3 DAX73AMB6E1 blinking charge light, not turning on

Ok I will remove PL12, that will also give us a better idea where the problem lies.

[rccrasher65]

Re: Hp Probook 455 G3 DAX73AMB6E1 blinking charge light, not turning on

Ok I will remove PL12, that will also give us a better idea where the problem lies.

Nice clean removal of PL12, no issues, protected all surrounding components. short is on opposite side of PU11. PU11 side measuring 48.5 ohms. Opposite side measuring 0.4 ohms. I'll post pic of board later. If any tests can be done let me know.Thank you

[rccrasher65]

Re: Hp Probook 455 G3 DAX73AMB6E1 blinking charge light, not turning on

Nice clean removal of PL12, no issues, protected all surrounding components. short is on opposite side of PU11. PU11 side measuring 48.5 ohms. Opposite side measuring 0.4 ohms. I'll post pic of board later. If any tests can be done let me know.Thank you

Power supply should be here on tues.