hi all,

So I spent years being a laptop technician diagnosing and fixing hundreds of thousands of laptops with issues replacing parts. Having questioned actually what if I could go the whole way and replace the components rather than the full part of set myself a task of fixing a laptop that doesn’t power up.

My knowledge is a little limited however using a multimeter and testing voltage from the D.C. socket to the power switch which connects via a separate board to the opposite side of the pcb with the D.C. socket. Tested the switch with a circuit test as well as D.C. to the sides of capacitors all of which show the correct voltage. Is there something else circuitry basics I’m missing which would stop it operating? I’ve tested the above whilst pressing the power switch also and the results don’t change.

Tips and tricks would be appreciated or excellent articles on this to help. To make it easier to visualise I’ve attached a picture

Thanks
Mike

 

hi all,

So I spent years being a laptop technician diagnosing and fixing hundreds of thousands of laptops with issues replacing parts. Having questioned actually what if I could go the whole way and replace the components rather than the full part of set myself a task of fixing a laptop that doesn’t power up.

My knowledge is a little limited however using a multimeter and testing voltage from the D.C. socket to the power switch which connects via a separate board to the opposite side of the pcb with the D.C. socket. Tested the switch with a circuit test as well as D.C. to the sides of capacitors all of which show the correct voltage. Is there something else circuitry basics I’m missing which would stop it operating? I’ve tested the above whilst pressing the power switch also and the results don’t change.

Tips and tricks would be appreciated or excellent articles on this to help. To make it easier to visualise I’ve attached a picture

Thanks
Mike

It is all about productivity and efficiency. I don't think there is a manual method of reliably diagnosing a board, ordering parts, desoldering / resoldering and testing that will pay for your time vs just buying a new module.

If you have way more time than money, then it could be a hobby to diagnose and repair. If you'd rather make money instead of a hobby, you might want to work at mcDonalds during the hours that you are not busy replacing modules on laptops.

You'll spend dozens of hours trying to track down problems. Then you'll track back an issue to some proprietary chip.

 

Appreciate the advice it was something that became a bit of an interest of mine as we used to send our boards off to repair for around £60 vs over £200 for some males and models new boards

 

I used to work for a company that did component level board repairs in what I still think is a remarkably low tech way. We had schematics, multimeter, and oscilloscope.
We (the 'engineers') would get a batch of faulty boards and our job was to fix them however we could - including trial and error. Carefully recording the initial symptoms and every measurement made and which part replacement fixed it. By the time you have done 100 or so boards you can produce a flow chart based on the symptoms, what to measure and what to replace based on the measurements made. Then the folk on the line followed the flow chart and could fix between 80% and 95% of the boards. The ones which were not fixed were scrapped. This way the repairs were quick and cheap.

The problem is that you can't do this for one board absent a schematic.

 

I get what you mean known issues with certain boards etc we had the same with overall repairs could follow a flow diagram really wasn’t overly difficult.

Well I’ll take it on board and see what I can come up with bit of a hobby really at the minute just like to learn new things

 

I used to diagnose and repair IBM PC boards and XT clones at the component level when it was cost effective to do so.
What I had to do back then was to remove the BIOS EPROM chip and replace it with a jumper cable wired to SRAM that was programmable from another PC. Thus I was able to enter my own test code and hence test the whole board, CPU and all memory and peripherals right from power-on reset.

 

As other said it's not cost effective to do extended repairs on commodity components like laptop parts. In the few areas where the repair of such complex boards is economical (i.e. the acquisition boards for some high-end scopes) then the manufacturer usually has put up a test rig with test instruments and special software plus a ton of documentation. Failing that (i.e. you have no diagnostic tools for that board and no documentation) it's pretty much down to trial and error and even if you're only assuming minimum wage it ends up being uneconomical when working replacement boards can be found on places like ebay for $80 or something like that.

The only exception are easy to spot issues like leaked capacitors but even then you have to think twice as there might be subsequent damage that is not visible. Replacing some connector can be worth it, if you can find a fitting spare.

In general, with commodity stuff like laptops I wouldn't bother with anything more than module/board swaps.