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Issues with replacing Dead Laptop Motherboard...

tk3000

Jun 19, 2022
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Jun 19, 2022
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My venerable and old laptop (Toshiba Satellite P75-A7200 equipped with an i7-4700MQ, circa 2014) and previously a powerful machine during its heyday is no more. Have been using it for many years, but about 3 months ago it went kaputt for no apparent reason (left it on overnight [normally it goes to standby mode after some idle time], and in the morning it was cold dead with no boot, no post, no leds; nothing at all).

Since the 1990s I have been building custom desktop computers, etc; but it has been few years since my last built one and for the last 15 years I have built very few desktop computers sporadically. So, I am not abreast of the new development in terms of computer hardware, etc.

As aforementioned, the laptop was dead. I went ahead and took it apart, removed the motherboard and performed some basic tests - continuity, resistance, and then volt injection. Soon, I realized that the likelihood of fixing it was not high, and it would be very time consuming. So, I went ahead and ordered another motherboard (presumably refurbished) on aliexpress of all places (not recommended really)

Subsequently, installed the motherboard with the processor, memory, and ancilliary systems and subsystems connected. Once most of of the system was assembled, I tried to turn it on but the system not even boot up, nor POST or no nothing. When the power button is pressed it lights up for a split of a second and then goes off and nothing happens (no fan, nothing on screen, nothing...). When it is connected to the power supply the the power indicator led lights up, and when the battery is installed the battery charging light lights up as well; other than that, there is no sign of life.

But one thing went amiss, I I forgot to affix in the back of the new motherboard the thin small cpu bracket. Since it is a small and very thin bracket that seemed to be an integral part of the motherboard; I did not notice its presence or absence. Anyhow, the heatsink is making good contact with the cpu; so even though it is not putting enough pressure on the cpu die, the cpu should not overheat so fast to the point that it would not even boot up at all -- at least that is an assumption I am making.

Any insights would be appreciated.
 

Bluejets

Oct 5, 2014
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presumably refurbished

All that means is they ripped it out of a (hopefully tested and working) laptop.
Doing any repairs on these old machines is iffy at best.
For one thing, they were never made to be repaired.
 

tk3000

Jun 19, 2022
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Jun 19, 2022
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All that means is they ripped it out of a (hopefully tested and working) laptop.
Doing any repairs on these old machines is iffy at best.
For one thing, they were never made to be repaired.
Sure enough, modern electronics circuitry in general are not made to be repaired. And that is particularly true for laptops motherboards. Besides, the expertise and labor cost required to repair modern electronics often far outpace the cost of a new one.
 

dave9

Mar 5, 2017
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Mar 5, 2017
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I'd assume the new board is DOA and seek a refund.
 

kellys_eye

Jun 25, 2010
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Jun 25, 2010
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Did you test the power pack (on load)? I've often found dodgy power packs are the cause of a problem and not the actual PC/laptop.
 
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