Hi,
Thanks for the reply.
I've opened another thread, please see [URL="https://www.badcaps.net/forum/troubleshooting-hardware-devices-and-electronics-theory/troubleshooting-laptops-tablets-and-mobile-devices/3592135-hp-probook-455-g8-charging-but-doesn-t-turn-on"]here[/URL].
Thanks.Hi,
Thanks for the reply.
I've opened another thread, please see [URL="https://www.badcaps.net/forum/troubleshooting-hardware-devices-and-electronics-theory/troubleshooting-laptops-tablets-and-mobile-devices/3592135-hp-probook-455-g8-charging-but-doesn-t-turn-on"]here[/URL].
double_DD
Member
Last Activity: 03-17-2025, 06:06 AM
Joined: 03-18-2024
Location: Zagreb
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HP Probook 455 G8 charging but doesn't turn ON
Hi all,
Unfortunately I cannot/don't know how to edit my last query, so I'll create another one instead.
So I've received this laptop to try and fix it. There were 2 blown components - small inductor and cap, both on Vin (main power rail) on the IN pins of the 0.75V chip (SY8388RHC). I've replaced that chip and the nearby 0.75V_DEEP_SUS (same type), and of course both of blown components. There was still a short on 3V coil, which went away when I replaced PI3DPX1207C chip next to usb-c port (as it was overheating). Luckily I have older non-working 455 G7 for the spare parts.... -
How can I be sure that my EC chip is dead?
Hi all,
As the title suggests, how can I be sure that my EC chip is really dead?
I've recently gotten into this hobby of laptop repairs, and have successfully brought back to life a couple with some easy fixes, mostly shorted caps.
Now I'm working on HP Probook 455 G8, that had some "devil" run around on 3V line, burning a bunch of stuff. Luckily I have a dead 455G7 (for spare parts) so I managed to fix it (swapped burned parts) to a point that it will charge (both on barrel jack and usb-c), but it doesn't want to turn on. There is a 3V3 on a keyboard... -
Thanks. I've tried searching via that text as well, but with no luck.Leave a comment:
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HP Thunderbolt dock G2 - "fixing" it so it can work without original HP charger?
Hi guys,
I do hope this is not off-topic.
I have this mentioned HP dock which is half-defective, as it sometimes work and sometimes not. But that's not my main issue at the moment.
I don't have any more original HP charger, and I would like to "fix" the dock so I can use it without it. Has anyone tried it, or maybe does someone know how to effectively bypass the "comm" pin of the charger?
Maybe someone has a schematic that would be useful? There are markings on the board that say P&Q 2019 CM-4 94V-0 E162264, but when I try searching... -
Hi,
I also need boardview for this laptop. Did you manage to find it anywhere?
Thanks!Leave a comment:
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Update:
Initially, the short was gone and I was able to connect the battery to the board and to charge it.
However, once I connected everything to the board and half assembled the laptop, then one of the CPU combined mosfets decided to die, so now I have again short on the main rail.
Now I just need to find and buy MPPX 8694 (not exactly sure what the last 2 letters are, as they differ on various AliExpress sellers).
Another interesting thing that maybe someone can explain it's functionality:
This laptop has a "[B]battery reset button[/B]"...Leave a comment:
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Well colour me stupid! I've removed those messy caps and the short is mysteriously gone. Apparently I've been chasing my own tail for the last month or so. No wonder I couldn't find anything with thermal camera. ðŸ˜
And I've replaced all of them with brand new ones.
The weird part is, I'm almost 100% sure that when I originally removed those caps, short was still present. So either I'm remembering wrong, or removing and putting back other components somehow disappeared the short. Or some of the mosfets I've put back are not properly soldered on.
Anyhow, now checking...Leave a comment:
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This is exactly what I was thinking lately, that maybe my bad soldering created another short around those caps. This is the first thing I will check next.
I removed the bad caps, and put back only the good looking ones. There's also a chance that I've damaged them when putting them back badly.
Regarding the cap next to the fuse, I will definitely check it closely. Thanks!Leave a comment:
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Thank you for a detailed process of examination and explanation.
Since this particular laptop was received as "liquid damage", my testing path was a bit different. For start, I never connected motherboard to power supply. I opened it, noticed some corrosion -on the first picture in last post, where a wire is soldered and some messy caps, corrosion was present all around those messy caps, then up around the fuse and on the connector on the upper part (this is screen connector). I took those caps out, cleaned everything with IPA, and put still good caps back. That's why they're...Leave a comment:
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Hi [USER="295753"]mon2[/USER] , thanks for the reply!
I do believe it is L13 from Yoga series (it's not mine, I got it to try and repair it).
I don't understand this image that you've sent, but 2 posts up is a picture of my motherboard. As you can see, heatsink and everything else has been stripped of, it's a bare motherboard, and with thermal camera I cannot find absolutely anything getting even a bit warmer when 5A is applied. I do not think that CPU is shorted because a) resistances at picture above I think are normal and b) even with CPU mosfets removed...Leave a comment:
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Hello everyone,
Let me try to revive this post, maybe I could get some help this time.
The story is:
I have this Lenovo L13 gen3 213037-1N laptop, water damaged, no schematic, and I've identified a short on a main power rail. Spent silly $$ to buy thermal camera.
However, I cannot find what is shorted. I've tried inserting voltage on various points on main rail, but NOTHING GETS FREAKING HOT. I've inserted from 0.9 to 19V, board always uses only 0.45-0.5 V with max current allowed. So something is taking 5A without getting hot! There are several "combined...Leave a comment:
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Green areas are caps that are short to ground (0ohm resistance), purple are resistance coils to ground (bottom right coil is currently missing, removed to isolate input from output, so values are on each side). I haven't seen any coils or shorts on the other side, just some chips (Realtek, ThinkShield...) and connectorsLeave a comment:
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Board number is LFR-1 intel 213037-1N, if some other info is needed please let me know. Thanks!Leave a comment:
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Lenovo L13 gen3 (2023)
Hi guys
I have received this laptop to try and repair it (and to learn more in the process).
It was liquid damaged, I found some corrosion near the screen cable that I cleaned. Now I'm left with a short on main power rail (19V).
I was hoping that it would be something simple as a shorted cap around a liquid damaged area, but no.
My problem is, I cannot identify what is shorted. I've inserted 0.9V (to be on the safe side) on mail power rail, and the voltage drops to 0.4V with the max current drawn allowed of 4.8A.
However, the board is cold... -
Hi guys,
Just a short introduction:
I'm a 40+ electrical engineer, originally from Croatia, currently living in Switzerland, who likes to tinker with and repair anything and everything related with electricity.
My latest hobby is laptop repair. So I thought I'd join in and learn more from smarter people around the world!
Mostly here to listen in but would be glad to contribute as well.Leave a comment:
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