Interesting information, all this helps understand the laptop better. Thank you very much for taking the time to help around the forum and for your effort.

I will look into it. It may take some time and I let you know here later how it went. Hope this aspire will work soon.

Again, thank you, it was helpful and clarified some of my doubts.

Hello again!

I finally replaced whatever was on the GPU and chipset for a thermal pad with a 21w/mk grey one (1st photo).

Though the final work looked fine to me, as I suspected, it didn´t turn on after reassembled. A small detail, this time, when opening this 5742G I noticed something I hadn´t seen before: there is this white ribbon cable that seems connected to the power button (2nd photo), that looks chipped where it has this metal lines. One of them is half-missing - could this be the reason why it used to turn on before I opened it and now it doesn´t (photo 3, detail with arrow)?

A few years ago, the laptop went for repair because it wouldn´t turn on. But the technician didn´t fix anything and still damaged the plastic connector that holds this exact ribbon cable. I remember we argued and it went back for fixing it, but he never replaced the ribbon cable and I remeber it had a slight damage.

I dislike opening this laptop because of this: the ribbon has to be removed every time I have to get to the fan/cooler. I try to be careful but just removing and putting it back again may have damaged this ribbon even further.

What do you think? Anyone has an idea?

I´m looking for the number of this ribbon cable, to see if it may be this.

It´s just strange that it was turning on but disconnecting and now, after opening and putting all back again, it doesn´t even give any signs of life… :(

BTW, I haven´t tried the electrician putty yet.

@jackE

I had been searching for it but had to check the number to be sure.

Like you say, that flex or ribbon cable is folded in that part you say overlaps. This is because the cover pressed it down, but I'm not sure it' s damaged there. It did stop connecting after I opened it this time.

I will look for that ribbon cable and give it a try. Thanks. 😃

Besides, I don´t know what else may be. Maybe I´ll give up trying to fix this one - it´s beyond my abilities.

You see that photo above from Aliexpress you uploaded? The ribbons on that photo are folded. That´s what I meant. You can´t see it on my photos of the flat cable I have, but it´s folded too.

And true, the ribbon is held in place by a plastic wedge - I checked and it seems to be pushed enough and well locked to me, but well maybe it isn´t making a great contact. So I will try to replace this ribbon.

My only doubt is how do I glue it to the power button circuit? I´m sorry to bother, but do you know if it needs any special glue?

You can see it glued in this photo below.

BTW, today I found that Acer no long has the page for support with manuals and downloads for this computer. I understand, it´s an old laptop but still it´s a sad because I see many people still using them. Sure, that at this age, many 5742G start having all kinds of problems but the ones that still have this laptops working can have a need for manual or others.

I don´t know why everyone keeps telling me that this ribbon cable isn't glued to power board, because I tried to remove it carefully and it was sticked to the inside. It looks like glue or some adhesive tape.

Here is an example (NEW70 LS-5893P, the yellow circle indicates where the cable is "glued"):

You´re right, I should have remembered that every circuit has to be soldered to make good contact. It´s just not a subject I know well.

It is also glued and that was what I could see just peeking. This morning I peeled it all to see what is underneath and in fact it is soldered and then has glue to hold the cable an the plastic cover over it:

Thank you for your patience. I had decided to try it. It´s easier than soldering, which is something I never did. It would be interesting though.

I bought it to give a try.

I´m also looking for another computer and looking into Acer again. This one had heating issues but it was actually not that bad for a laptop of 2010 or 2011. It held on for a long time.

Thank you. :)

Now many laptops are so thin that I wonder how they cool them at all!

Don´t even know what that is! 😐️ But sounds bad. They don't use copper anymore?

Sorry for taking so long to reply, this has been a hectic week. As I said, I´m going ahead and I´m waiting for the power button board circuit and will give it a try. :)

If that doesn´t work, I´m already looking for a new computer - I will see if I find an Acer laptop that does what I need.