Toshiba Old Laptop turning ON but no screen OR only "starting windows then nothing......

electronpusher

Member (✔)
i have a tricky Laptop problem that as a repairer myself , i cant quite nail. and love some help.. Problem is the usual "wont start and blank screen- but for months!! sometimes start normally and most not- so intermittent!!! worst fault haha
OK- What it isnt- I have switched out ram and PS and its not over heating ect as i service it but that would be once it s hot and OH. I have also changed SD HD with another and fresh windows install so its not windows or t the HD!!
Problem-- Push Power button (3 volts ok?) and power light and mouse comes on each time but nothing on screen OR i see 'windows starting" but then nothing. So kill power a couple of times and after 1-4 tries finally get into windows and DESKTOP and if that far, NO failure or blue screens or shutdowns and runs OK all day.... , no error mesgs and faultless , its just getting to desktop sometimes and then perfect all day
So my electronics and M/B knowledge is leaning toward Weak Caps that are loaded harder? on start but less once computer on and thus runs all day-
Laptop is 13 years so YES, caps will be worn Maybe Bios chip ropey or super IO BUT by now they should have failed totally? Super IO is keeping the mouse on and power on so not a board short plus i checked all that when pulled M/B to check obvious shorts and burnt components Also Power button not always work to force shutdown to try 1-4 restarts so m/B not always responsive, so i pull plug.
Battery and bios battery also removed and replaced . When i try to duplicate this fault HOT, i cant do it, only seems to happen after cold night then start- leading me to think weak cold caps not already ran and warmed ? when i pulled board and tried restarts they worked every time as M/B was warm and voltage filled generally. Is the Power button 3V needed AFTER the board is on, if not then that cant be it as mouse is on every time just wont get going to windows My next step is to monitor the 19V main rail and maybe even scope it for A/C noise when i turn it on cold and see if i can detect weak voltage and ripple from bad caps but not bad enough to have it run all day without fault? hmm Screen problems detected? but screen works perfectly all day and everything else too for months with this problem so i dont want to start reballing chips and make it worse perhaps.. Of course dumb windows says it need repair when it does start after restarts as thats it default position but it NOT windows or the drive.. This is M/B related as all else has been replaced or substituted to rule out....
Inspection- no corrosion or anything obvious. now it hot here in AUST, it might start each morning first time leading me to think warm nigh warm caps?
or simply a chip that is intermittent and hasnt failed yet. Any ideas appreciated as its my mums and valued to her and i like learn what this is or could be...

thanks for any help..
 

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desktops & Laptops
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i have a tricky Laptop problem that as a repairer myself , i cant quite nail. and love some help.. Problem is the usual "wont start and blank screen- but for months!! sometimes start normally and most not- so intermittent!!! worst fault haha
OK- What it isnt- I have switched out ram and PS and its not over heating ect as i service it but that would be once it s hot and OH. I have also changed SD HD with another and fresh windows install so its not windows or t the HD!!
Problem-- Push Power button (3 volts ok?) and power light and mouse comes on each time but nothing on screen OR i see 'windows starting" but then nothing. So kill power a couple of times and after 1-4 tries finally get into windows and DESKTOP and if that far, NO failure or blue screens or shutdowns and runs OK all day.... , no error mesgs and faultless , its just getting to desktop sometimes and then perfect all day
So my electronics and M/B knowledge is leaning toward Weak Caps that are loaded harder? on start but less once computer on and thus runs all day-
Laptop is 13 years so YES, caps will be worn Maybe Bios chip ropey or super IO BUT by now they should have failed totally? Super IO is keeping the mouse on and power on so not a board short plus i checked all that when pulled M/B to check obvious shorts and burnt components Also Power button not always work to force shutdown to try 1-4 restarts so m/B not always responsive, so i pull plug.
Battery and bios battery also removed and replaced . When i try to duplicate this fault HOT, i cant do it, only seems to happen after cold night then start- leading me to think weak cold caps not already ran and warmed ? when i pulled board and tried restarts they worked every time as M/B was warm and voltage filled generally. Is the Power button 3V needed AFTER the board is on, if not then that cant be it as mouse is on every time just wont get going to windows My next step is to monitor the 19V main rail and maybe even scope it for A/C noise when i turn it on cold and see if i can detect weak voltage and ripple from bad caps but not bad enough to have it run all day without fault? hmm Screen problems detected? but screen works perfectly all day and everything else too for months with this problem so i dont want to start reballing chips and make it worse perhaps.. Of course dumb windows says it need repair when it does start after restarts as thats it default position but it NOT windows or the drive.. This is M/B related as all else has been replaced or substituted to rule out....
Inspection- no corrosion or anything obvious. now it hot here in AUST, it might start each morning first time leading me to think warm nigh warm caps?
or simply a chip that is intermittent and hasnt failed yet. Any ideas appreciated as its my mums and valued to her and i like learn what this is or could be...

thanks for any help..
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