Razer Blade 15 (2020) missing components

[sect-sin]

Re: Razer Blade 15 (2020) missing components

Hi again,

Found a better frame, now the diode is visible, though I still don't know what it is. Schottky maybe?

Cheers,

sect-sin

[Sephir0th]

Re: Razer Blade 15 (2020) missing components

You're saying, there are no unexpected shorts around the 3.3V/5V controller? Missing components are usually a bad thing if the board was powered on, but in this case it shouldn't be responsible for blowing a fuse.

However, there's definitely something wrong in charging area and "no short found" just isn't enough to work with from here. We need measurements and in best Case a (self written, maybe partial) schematics to understand what is going on and what connects to where. The guess work ends here for sure.

[sect-sin]

Re: Razer Blade 15 (2020) missing components

You're saying, there are no unexpected shorts around the 3.3V/5V controller? Missing components are usually a bad thing if the board was powered on, but in this case it shouldn't be responsible for blowing a fuse.

However, there's definitely something wrong in charging area and "no short found" just isn't enough to work with from here. We need measurements and in best Case a (self written, maybe partial) schematics to understand what is going on and what connects to where. The guess work ends here for sure.

Sephir0th,

I made a small schematic of the power-in area with some rudimentary traces, see attached. Now that you mention shorts, I checked again, and the board side of the blown fuse marked X shows 0,71 kOhm to ground, which may be a partial short. Voltage injection brings me nowhere though, as it is drawing 0,2 amps only, and nothing lights up.

Of particular interest to me is the AON 6854 MOSFET which connects VDC from the adapter with the battery - is this a MOSFET responsible for regulating the voltage charging the battery?

Please let me know where to go from here or what to measure further.

Thank you very much in advance!

Cheers,

sect-sin

[boster27]

Re: Razer Blade 15 (2020) missing components

Currently working one of these boards. Attached the picture you requested.

In this particular case there was a blown battery fuse and a bad cap near the processor. Replaced both and the board turns on, but LED only blinks green and the CPU gets hot, no POST; so there may be component damage.

In your case, have you tested all the fuses? This board seems to have a lot of fuses.

[sect-sin]

Re: Razer Blade 15 (2020) missing components

Currently working one of these boards. Attached the picture you requested.

In this particular case there was a blown battery fuse and a bad cap near the processor. Replaced both and the board turns on, but LED only blinks green and the CPU gets hot, no POST; so there may be component damage.

In your case, have you tested all the fuses? This board seems to have a lot of fuses.

Hi boster27,

You are a DEMIGOD, thank you so very much for your photo. I now know that my missing diode is an SR24 schottky. I will be eternally grateful for your help.

Yes, I checked all the fuses, all are fine except the battery fuse marked X, which keeps blowing. There probably is a partial short somewhere, which I need to track down.

Could you measure the resistance to ground of your battery fuse?

If you need any measurements from me, I am happy to do them, just let me know.

Cheers,

sect-sin

[sect-sin]

Re: Razer Blade 15 (2020) missing components

Hi all,

So the SR24 diode arrived, as well as a new AON6854 and AN6982 MOSFETs. I replaced all of them, soldered the diode, replaced the fuse. Unfortunately the fused voltage rail still shows 0,72 kOHM, and the notebook does not power on (no lights, nothing).

I am at a loss on how to continue. Could somebody help me with this?

Cheers,

sect-sin

[Sephir0th]

Re: Razer Blade 15 (2020) missing components

Of course the board won't work by just adding the missing components. They were obviously removed for some reason.

So now the real troubleshooting begins:

Full overview of the board, each coil and main power rail, voltages and resistances to GND. We'll move into the direction of the issue from there.

[sect-sin]

Re: Razer Blade 15 (2020) missing components

Of course the board won't work by just adding the missing components. They were obviously removed for some reason.

So now the real troubleshooting begins:

Full overview of the board, each coil and main power rail, voltages and resistances to GND. We'll move into the direction of the issue from there.

Sephir0th,

Yes, you are right, but nevertheless it was worth a (long) shot, the missing components might have been bad, and I would need them anyway.

I have attached two images showing resistances in green and voltages in red. Although I do not know what function every coil powers, but I do not think that any of them show any irregularities.

There is no voltage on any of the coils. 19V reaches only the first MOSFET. The AON6354 has 4,6V on the Gate, but nothing on either source or drain. I also checked ACIN on the charging chip, it only shows 0,25V.

It seems like somewhere a buck converter is blown, but I have no idea where/what to look for.

Cheers,

sect-sin

PS: I checked out your youtube channel and congratulate you on your move!. I subscribed and will be binge-watching everything you uploaded so far. I wish you the best with your filming endeavors!

[Sephir0th]

Re: Razer Blade 15 (2020) missing components

Good morning,

at first, thank you for the compliment.

Now back to the issue. Unfortunately your resistance readings are almost mpossible to read (please double check the quality), however, it seems like the issue is already in the charging circuit.

Check this resistor out. I guess this is the current sense resistor for the main power rail (or the other one upper left of this one. One of the them is connected to the coil for battery charging, but we're looking for the other one which is NOT connected to the battery coil.)

Voltage and resistance to GND please. We work from there, backwards or forward.

Regards

[sect-sin]

Re: Razer Blade 15 (2020) missing components

Good morning,

at first, thank you for the compliment.

Now back to the issue. Unfortunately your resistance readings are almost mpossible to read (please double check the quality), however, it seems like the issue is already in the charging circuit.

Check this resistor out. I guess this is the current sense resistor for the main power rail (or the other one upper left of this one. One of the them is connected to the coil for battery charging, but we're looking for the other one which is NOT connected to the battery coil.)

Voltage and resistance to GND please. We work from there, backwards or forward.

Regards

Hi Seph,

I am sorry about the resolution, it was fine on my machine, I guess the Badcaps forum engine scales it down. Need to take that into consideration for the future. Anyway, I have redone it, with larger red characters, see attached.

Resistance values of both CSR's check out. The bottom one is indeed the one connected to DC. When powering the board, no voltage is present on either CSR. Then I measured resistance to ground on the one CSR you mentioned, which shows 2,5 Ohms. This seemed awfully low to me, so I took the liberty to inject some voltage. This drew 1,5A @ 1.0V, and one of the five GPU dual MOSFET's (AOE6930) lighted up.

I have a good feeling that I might be onto something here. If you agree, I will order a replacement MOSFET, and keep you posted.

I really appreciate your help and nudging. Unfortunately I have not thought about checking resistance to ground of CS resistors, but I suppose there is still a lot to learn for me.

Cheers,

sect-sin

[Sephir0th]

Re: Razer Blade 15 (2020) missing components

It is a shorted high side mosfet, so Main Power rail shorted with one of the Sub-rails through a internal shorted Mosfet. 2.5 Ohms sounds more like CPU than GPU though. Can you show me which one is it? And then remove it and check again at current sense resistor. Regards

[sect-sin]

Re: Razer Blade 15 (2020) missing components

It is a shorted high side mosfet, so Main Power rail shorted with one of the Sub-rails through a internal shorted Mosfet. 2.5 Ohms sounds more like CPU than GPU though. Can you show me which one is it? And then remove it and check again at current sense resistor. Regards

Seph,

Sorry, that was a typo, I meant CPU, not GPU. Will desolder tonight and check whether short is gone, and will report back. Yesterday it was already too late for me.

I sincerely hope that it did not kill the CPU.

Cheers,

sect-sin

[sect-sin]

Re: Razer Blade 15 (2020) missing components

It is a shorted high side mosfet, so Main Power rail shorted with one of the Sub-rails through a internal shorted Mosfet. 2.5 Ohms sounds more like CPU than GPU though. Can you show me which one is it? And then remove it and check again at current sense resistor. Regards

Seph,

I removed the MOSFET, and the short is gone, resistance to ground of the CS resistor jumped to 1,8 kOhm. Since none of my donors have this MOSFET, I went ahead and ordered it, luckily it was available at a local dealer, so if all goes well, I should have it in house either tomorrow or Monday.

Will keep you updated.

Cheers,

sect-sin

[Sephir0th]

Re: Razer Blade 15 (2020) missing components

Of course you can replace it, but i have less hope for the device. Almost no CPU survives a high-side short...

[sect-sin]

Re: Razer Blade 15 (2020) missing components

Of course you can replace it, but i have less hope for the device. Almost no CPU survives a high-side short...

Hi Seph,

The operation has succeeded, but the patient is dead

After replacing the MOSFET, voltage is present on all coils, the notebook switches on, there is fan spin, keyboard backlight, LED powers up, CPU heating up, something resembling a CMOS battery removal power down and up cycle, but finally no post.

Do you think it is worth a last shot to try to rewrite the BIOS, or should I shed my tears and designate the machine as a RIP?

Cheers,

sect-sin

[Sephir0th]

Re: Razer Blade 15 (2020) missing components

Was the BIOS chip touched before? Maybe worth to do it. Also you should check whether it responds to CTRL+ALT+DEL.

And in case you want to make absolutely sure there is no issue anymore in VRM circuit you have to replace each semiconducter, so alle Mosfets/DrMOS related to CPU supply and the VRM Controller too.

Regards

[sect-sin]

Re: Razer Blade 15 (2020) missing components

Was the BIOS chip touched before? Maybe worth to do it. Also you should check whether it responds to CTRL+ALT+DEL.

And in case you want to make absolutely sure there is no issue anymore in VRM circuit you have to replace each semiconducter, so alle Mosfets/DrMOS related to CPU supply and the VRM Controller too.

Regards

Seph,

The BIOS chip was definitely never touched, and the notebook does not respond to CRTL-ALT-DEL or Caps-lock.

I replaced all MOSFET's, unfortunately no change in behavior. I do not have a replacement for the VRM controller, neither for the MOSFET drivers (this is not a DrMos design), but might as well get some and try that as well.

One more thing: is it normal for the PCH to heat up to 63C during "operation"? There is no heatsink on it, I was just wondering whether that is abnormally high.

I really appreciate your help.

Cheers,

sect-sin

[Sephir0th]

Re: Razer Blade 15 (2020) missing components

Sad to hear this. But yeah, a PCH can get pretty hot in working condition. It shouldn't burn your finger though. However, in this special case I wouldn't expect the issue in the direction of the PCH.

[down1nit]

Re: Razer Blade 15 (2020) missing components

I found this thread searching for 'razer "schottky"' since my schottky diode near the battery connection on my customer's Blade had a similar "poof" event. There were no other issues. Other than the traditional battery = spicy pillow. Razers and their batteries huh?

The diode I ended up ordering was NONE since I was able to find a diode with printed markings of x24x something on another donor board I had. They are quite common apparently. Searcher from the future: you might have a few!