Acer 5742G switches off at logo screen

so... I got a Acer 5742G laptop for free from a friend, but when i start it, it turns off after a few seconds.
the battery is faulty so there is no troubleshooting around that. the power adapter is working correctly i believe.
first to explain in detail... when i power on the laptop, it starts and shows the logo screen then shows <press F2 to enter BIOS> for about 1-2 seconds then it switches off.
there was one time when it started and i could access the BIOS and it stayed on, but when it restarts its giving me the problem again and it does that everytime. so i used a universal charger to test then it stayed on again till I exit the bios and restart then the problem starts again.. I opened the laptop to check for dust or loose connections but didnt see anything strange, after that it stayed on again the first time and after restart the problem continues... so I have been searching for sollutions and tried a few. the only thing I didnt do was removing the cmos battery because it is soldered and dont have soldering iron at the moment.. so its weird that it only stay on sometimes but thereafter switching off at the logo screen. any advice will be appreciated, thanx in advance

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JackE

With the battery removed, see if it will stay on. If not, remove a RAM module and try it again. If still shuts off, then remove HDD and try it again.

JanHendrik

Have tried all that, reseated ram and hdd. Still same problem

JackE

No. Not re-seat. Remove the RAM and SSD to see if it'll stay on. If still nothing, then remove the m.2 wifi card. Try it again.

JanHendrik

thanx will try that and will let you know

JanHendrik

tried that and no luck.... possibly the motherboard giving problems...

JanHendrik

tried it again and it stayed on now... so again it stays on once now and then...

JanHendrik

update:

so i did a bios reset by removing power sources and hold the power button in for about a minute and got it stayed on then did a bios update. at least now it stays on but for a few minute then it switches off. so i think its a overheating issue, it does get hot quickly but not unbearable hot.. will clean the fan and heatsink out. unfortunately the bios doesn't show cpu temp. will give feedback if everything is working correctly

JanHendrik

got too excited too quickly... i switched on and giving the same problem again....... its got a will of its own

JackE

Try to clean the gold-colored contacts on the RAM module and HDD connectors with a qtip cotton swab and denatured alcohol from HomeDepot. Also rub them gently with a soft cloth. Then try to repeatedly re-seat them in the mainboard connectors to help clean the enclosed contacts that you can't reach with the swab or cloth.

JanHendrik

thanx will do that, also going to desolder the cmos battery to do a decent bios reset.. cause i also noticed when i do a reset with the power button but date and time doesnt change.. will try to borrow a ram chip to test also. after removing power adapter and do a reset it stays on for about 10 seconds longer but also shuts down.

JanHendrik

cleaning doesnt help, still the same. sometimes after it shut down it will restart after about 5 seconds but loop for about 3-4 times then stays off.. dont think there is much hope left

JackE

What happens when you F2 into the BIOS on startup, then press F9 to load defautls, then F10 to save and exit the BIOS menu?

PS: Don't forget the remove the wifi card just in case that might've failed.

JanHendrik

tried with another ram chip but no luck. is the best option maybe to just throw it away?

JanHendrik

it shuts down just after i get the option to enter bios, so even if i press f2 i get a split second of the bios and then it shuts off. at a time when it stayed on i did load defaults in the bios but that didnt help... i did remove the wifi card, no changes.. at the moment i feel like theres nothing i could do to save him

JackE

You could try a full board solder re-flow if it's due to a solder fracture or failure. Sometime a reflow will even revive an IC chip. If it doesn't work out, you could always get a new mainboard for less than $50 from Aliexpress, a fairly reliable concessionaire like Amazon. Boards this old are sometimes warehoused stateside so delivery can be less than about a week if you're in the US or Canada. Otherwise about 4 or so weeks.

Image: https://us.v-cdn.net/6029997/uploads/editor/lq/ph6e97odbs3q.jpg

JanHendrik

Im from South Africa. will see what i can do or try tot find another board or maybe buy a new laptop. as I got it for free i just want to get it to work but will decide what im going to do. but thanx for the advice and help. i do appreciate your time