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

[rccrasher65]

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

You can open the RAR file with 7-Zip.

I would consider soldering work to be the last resort. And actually, there's one more thing to try. The most neat and orderly explanation I can think of would be if PR70 were shorted. It's not a common failure mode for resistors, but it can happen. It's an even nicer explanation if the board is turning on PQ8. That would create the path to ground we are looking for, and it would disappear when the board is unpowered.

Let's test this hypothesis (See attached pic #13):

- With the board unpowered, test the resistance of PR70. It's supposed to be 13k ohms.

- With power connected to the board, measure the voltage on the pins of PQ8.

Resistence on PR70 is 12.99 to 13.03K ohms I checked this a few times. With power connected to board PQ8 pin1-0.0mv pin2-0.9mv pin3-0.3mv

[BlueMidnight]

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

Well that's unfortunate. The hard way it is then. I'd recommend trying to inject voltage onto LIMIT_SIGNAL. Dial it up to 5V max for now and see if a short appears. Doing it this way allows you to increase the current and potentially feel PR70 or PR158 getting hot. (PR158 is the one in pic #12 labeled LIMIT_SIGNAL)

[rccrasher65]

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

Well that's unfortunate. The hard way it is then. I'd recommend trying to inject voltage onto LIMIT_SIGNAL. Dial it up to 5V max for now and see if a short appears. Doing it this way allows you to increase the current and potentially feel PR70 or PR158 getting hot. (PR158 is the one in pic #12 labeled LIMIT_SIGNAL)

Should I apply power at pin 6 on connector CN11? You mentioned that a few posts back, just want to make sure.

[BlueMidnight]

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

That is a good place to do it. There is also a test pad located at the top-right of attached pic #14, if you prefer.

[rccrasher65]

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

That is a good place to do it. There is also a test pad located at the top-right of attached pic #14, if you prefer.

I'll get at it tonight, had a busy few days. Are those the only components we are looking for to get hot, or our we looking for any hot component.

[BlueMidnight]

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

Well, that's the thing. There are only 2 ways "out" of LIMIT_SIGNAL on the schematic. There's the 13k ohm PR70, and there's the 2.1k ohm PR158. It's impossible to get the voltage reading you're getting with 330k above and those below. And there are even more components in series with those on the way to ground too.

So, we will test if there is a short to ground through one of those that just doesn't show up until you apply enough voltage. It's not super likely, but not impossible. If not, then there must be a short on some interior plane of the PCB, or on the surface (e.g. corrosion or conductive material).

[rccrasher65]

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

Well, that's the thing. There are only 2 ways "out" of LIMIT_SIGNAL on the schematic. There's the 13k ohm PR70, and there's the 2.1k ohm PR158. It's impossible to get the voltage reading you're getting with 330k above and those below. And there are even more components in series with those on the way to ground too.

So, we will test if there is a short to ground through one of those that just doesn't show up until you apply enough voltage. It's not super likely, but not impossible. If not, then there must be a short on some interior plane of the PCB, or on the surface (e.g. corrosion or conductive material).

I applied 5V to CN11-pin 6 brown wire. no hot components, I then slowly increased to 8v still nothing hot. My power supply is a cheap pos! you can only do one thing or the other, meaning you can use it in constant voltage mode or constant current mode. can't do both. It's one or the other. I'm interpreting what you actually wanted me to do was set my voltage to 5V, and then ramp up the current. well this junk doesn't work that way. Sorry for the rant.

[BlueMidnight]

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

Does the actual voltage on LIMIT_SIGNAL rise up to the set voltage?

[rccrasher65]

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

Does the actual voltage on LIMIT_SIGNAL rise up to the set voltage?

I set voltage to 5V as you requested, I did then check voltage on limit signal, it had 5v on it. I did not check when ramped up voltage to 8V, just was feeling for hot components at that point.

[rccrasher65]

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

Does the actual voltage on LIMIT_SIGNAL rise up to the set voltage?

Yes it does.

[rccrasher65]

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

Yes it does.

what ever voltage I apply to CN11. will show up on limit signal. I applied 5V, 6V, 8V, 10V, all will show up on limit signal, still no hot component.

[BlueMidnight]

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

Okay, the 1-2 mV on LIMIT_SIGNAL you were reading before would require a path to ground of no more than roughly 20-30 ohms if the ID resistor is 330k. It seems that the resistance must not be too too much lower than that. The current draw isn't enough to cause your power supply voltage to sag.

The fact the voltage didn't sag, and nothing got hot, indicates those two resistors are okay at least. So, the last thing I'd like is proof that current is taking an alternate route to ground. Does your power supply show how much current is being drawn?

(I'm trying to avoid more difficult soldering jobs, so I'm going with this voltage-injecting method. But, the alternative way would be to disconnect those two resistors and see if you are still getting low readings on LIMIT_SIGNAL with the AC adapter plugged in.)

Do note that my earlier recommendation of 5V max is to try to keep ADP_A_ID and OCP_A_IN less than 6V in even a worst case scenario. That's an educated guess for the absolute maximum voltage rating of the I/O pins on the EC chip. 10V should not have harmed anything, though, if the part of the circuit involving PQ20 is working. But any higher is not good.

[rccrasher65]

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

Okay, the 1-2 mV on LIMIT_SIGNAL you were reading before would require a path to ground of no more than roughly 20-30 ohms if the ID resistor is 330k. It seems that the resistance must not be too too much lower than that. The current draw isn't enough to cause your power supply voltage to sag.

The fact the voltage didn't sag, and nothing got hot, indicates those two resistors are okay at least. So, the last thing I'd like is proof that current is taking an alternate route to ground. Does your power supply show how much current is being drawn?

(I'm trying to avoid more difficult soldering jobs, so I'm going with this voltage-injecting method. But, the alternative way would be to disconnect those two resistors and see if you are still getting low readings on LIMIT_SIGNAL with the AC adapter plugged in.)

Do note that my earlier recommendation of 5V max is to try to keep ADP_A_ID and OCP_A_IN less than 6V in even a worst case scenario. That's an educated guess for the absolute maximum voltage rating of the I/O pins on the EC chip. 10V should not have harmed anything, though, if the part of the circuit involving PQ20 is working. But any higher is not good.

no , my power supply is just a cheap $40.00 Chinese POS. You can set it for constant voltage, or use it in current mode, where you can increase the current. It does not tell you how much of a load is being drawn, sorry!

[BlueMidnight]

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

Well, if there is a short somewhere on LIMIT_SIGNAL, then the solution would be to isolate that short by cutting the traces before and after. You could then run a jumper wire to bypass those traces.

The boardview file does not contain information about the routing of the board traces, so you will have to locate them yourself.

Look at the top contact of PR70 and the right contact of PR158 (as they are oriented in the earlier pics). Follow the traces along the surface of the board and through any holes (vias) until they join up with each other. Follow them until they reach CN11. Visually check for anything along that route that looks weird and might explain the short.

You're also looking for good places to cut those traces. A place right near each resistor would be best. Even better if there are no other traces right next to it at that spot. For CN11, it depends on which way the trace goes. If it disappears under the connector, it may be best just to lift pin 6 up to disconnected it from the pad.

Just look it over and get the lay of the land. Then report back.

[rccrasher65]

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

I'll try and do what you suggest, but I think now all this is well beyond my skill set. I do have the other board I would like to try and get going, or maybe even the board I pulled the two pads off of the charging chip. I don't want to waste your valuable time. I do certainly appreciate all you have done to walk me through this process. If we can I would like to turn to the other board, and give it a try.

[rccrasher65]

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

I'll try and do what you suggest, but I think now all this is well beyond my skill set. I do have the other board I would like to try and get going, or maybe even the board I pulled the two pads off of the charging chip. I don't want to waste your valuable time. I do certainly appreciate all you have done to walk me through this process. If we can I would like to turn to the other board, and give it a try.

I couldn't connect the traces. well beyond my skill set. I probably have a better chance of fixing those other 2 boards. the one with the two pads pulled off, or one with all the voltages present. let me know. Thank you again for all your help, and time!

[BlueMidnight]

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

Did you attempt to perform the cutting and soldering already? I was going to add some more detail once you'd taken a glance at everything.

Fixing the pad(s) on the other board would be 10x more difficult I'm afraid.

I'll need to glance over the schematic and boardview to describe the next steps on the board that had voltages present. Have you been able to extract the boardview file?

[rccrasher65]

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

I only attempted to follow the traces with no success. Combination of bad eyes and lack of knowledge. To me this board is a parts board. I have the others, that I would probably have more of a chance of success. I don't give up easy, but I also know my limitations. just like that dang rar file I still can't open, even with 7-zip. I also don't want to waist your valuable time. I would like to attempt the one with the voltages present first, If we can. I'm practicing soldering very fine copper wire, for an attempt at fixing PU20 missing pads. Thanks BlueMidnight for all your help. let me know what we can do next. I'm looking for a better microscope camera, then I can attempt to find those traces. I only have a small hand held one.

[rccrasher65]

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

I only attempted to follow the traces with no success. Combination of bad eyes and lack of knowledge. To me this board is a parts board. I have the others, that I would probably have more of a chance of success. I don't give up easy, but I also know my limitations. just like that dang rar file I still can't open, even with 7-zip. I also don't want to waist your valuable time. I would like to attempt the one with the voltages present first, If we can. I'm practicing soldering very fine copper wire, for an attempt at fixing PU20 missing pads. Thanks BlueMidnight for all your help. let me know what we can do next. I'm looking for a better microscope camera, then I can attempt to find those traces. I only have a small hand held one.

Well so much for that board, I attempted to cut trace, and a total failure, very hard to do with the camera I have. so. I can try again with the board with missing pads. I need to know where pins 1,2,3,and 4 go on PU20. I think I might be able to do this, going to give it a shot. Thanks BlueMidnight for your patience. Can you also resend those rar files, and boardview file. something must be wrong with the one I have. I still can't open it.

[BlueMidnight]

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

The boardview file is in this post. It is the same one I downloaded and am using. After you install 7-Zip, you can right-click on the rar file and choose to extract it. Alternatively, you can run 7-Zip and then use it's built-in file browser to locate the rar file and double-click it. After extracting the boardview file into another folder, you can use one of the recommended programs to view it.

Well if you ever do want to continue, the trace cutting can be done right near each resistor. For each cut you want to make, you actually ideally make 2 shallow cuts (going through the trace and no deeper) right next to each other using a very sharp razor blade or hobby knife. Then the little sliver in between the cuts can be lifted out. That way you know the cut ends can't touch. If the cuts are nice and close together you can still make a solder bridge across the gap to reconnect the trace if needed. If you get that far, then we'll worry about the jumper wire step.

For the board with damaged pads...

PU20:
Pin 1 -> Bottom of PR23
Pin 2 -> Bottom of PR22
Pin 3 -> Right side of PR13
Pin 4 -> Bottom of PR20

See attached pic #15