Are there general guidelines that tell what resistance each voltage rail in laptop should have?
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Re: Resistance of rails in laptops
no, only your own experience -
Re: Resistance of rails in laptops
What is the best multimeter to check bord error ?Comment
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Re: Resistance of rails in laptops
Meters vary in features, cost and how rugged they are. Recently purchased a Fluke 87V/E2 from a local reseller at a nice discount. Too expensive to buy at full retail price.
You may want to read the articles on EEVBLOG about this topic:
EEVblog Brymen BM235 Multimeter is what they recommend.
There are many on Aliexpress at varying prices.Comment
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Re: Resistance of rails in laptops
Thanx all...❤️❤️❤️Comment
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I am looking at an A2337 and found this for the order of power rails and what they do. Can this be confirmed before I dive into hunting down power rails that do not exist or are not neccisary?
- PPBUS_G3H (12.6V-12.8V)
- This is the main power rail that supplies power to the entire system. Check this rail first, as it must be present for other power rails to work.
- PP3V42_G3H (3.42V)
- This power rail is derived from PPBUS_G3H and is used to power the SMC (System Management Controller) and other essential circuits. It should be present if PPBUS_G3H is working correctly.
- PPVRTC_G3H (3.3V)
- This
- PPBUS_G3H (12.6V-12.8V)
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Working on a Zotac RTX 3070 with: PEX at 1v and 6.3 ohm., the 1.8v rail is at 5 ohms. mem is at 1.3v and 42 ohms and the Vcore is 0.7 ohms ( about 0.4 ohms above my background reading) at 0.75 v.
Question, are the PEX and 1.8v rails resistance too low? Have no video so trying to decide if dead core or something fixable. Dont have oscilloscope so playing with possible bios problem too.
Advice on resistance values for pex and 1.8v rails appreciated.
Thanks -
Hi guys, i was wondering, i've got 9Ohms on Vmem, one of the mosfet was shortet to ground, so i've desoldered hi and low mosfets nad still low res, then i removed all of the memory chips, and the resistance is still low, so did you had maybe a card with that low res on memories, and the card was working fine ?
Removed the U1866Q and still without result, i dont have thermal cam so can't see where is hot spot when incjeting voltage.
The resistance on core is ok 0.1Ohm ((Power 0.8V when on)
Resistance on 12V 4K ohms (Power present when on)
Resistance on 12V PEX 4K ohms... -
Laptop model: Sp513-54n-74V2
Testing power rails (separated by chip) reveals:
19V_DCBATOUT - (active)
5V_AUX_S5 - (active)
5V_S5 - (active)
3D3V_AUX_S5 - (active)
3D3V_S5 27Ω - (good) - enabled by Nuvoton chip
1D8V_VCCIN_AUX - (good) - enabled by 1D8V_S5 PG signal -- (dependent on 3D3V_S5)
1D8V_S5 41Ω - (good) - enabled by 3D3V_S5 PG signal
1D05V_VNN_BYPASS - (good) - enabled by 1D8V_VCCIN_AUX PG signal... -
You have a laptop that does not power on, powers on but shows no image, crashes, etc… You want to fix it but you don't know where to start.
There are 2 situations:- You just want your laptop fixed
- You want to learn about fixing laptops
Sorry, but if you're in situation number 1, we recommend you to use the services of a trustworthy professional repair shop.
Unfortunately, if you're not serious about learning, you will waste your time and money, and you will make us waste our time as well.
If you are in situation number 2, then please continue and...
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