Just an update on this.
Received the new ISL chips and Mosfets today.
Must have damaged the old ones swapping between boards too many times.
1 was dead short, another had 80ohms between drain and source.
Soldered in the new ones and board seems be working (get the flash codes for missing LCD which is correct).
I have resoldered the EC from the other board for now until such time I get a replacement, or use that board for spares.
benwaterson
Badcaps Veteran
Last Activity: 03-30-2025, 02:45 AM
Joined: 08-13-2008
Location: Milton Keynes
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I swapped the mosfets from the other board, so can't compare them now. (Will be able to when new laptop arrives).
I did quickly check resistances earlier and all were at least in kiloohm range.
I will check the gates and see if they are all switching on.Leave a comment:
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Yes, both ISL9538...Leave a comment:
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19.7v (just AC, no battery)
[ATTACH=JSON]{"data-align":"none","data-size":"full","title":"image.png","data-attachmentid":3264495}[/ATTACH]19.7v (just AC, no battery)
[ATTACH=JSON]{"data-align":"none","data-size":"full","title":"image.png","data-attachmentid":3264495}[/ATTACH]...Leave a comment:
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PROG is measuring 105k to GND, so should be 12v? (PR4410)
[ATTACH=JSON]{"data-align":"none","data-size":"full","title":"image.png","data-attachmentid":3264453}[/ATTACH]
[ATTACH=JSON]{"data-align":"none","data-size":"full","title":"image.png","data-attachmentid":3264454}[/ATTACH]PROG is measuring 105k to GND, so should be 12v? (PR4410)
[ATTACH=JSON]{"data-align":"none","data-size":"full","title":"image.png","data-attachmentid":3264453}[/ATTACH]...Leave a comment:
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It was definitely just the chip itself heating.
I have swapped the ISL and Mosfets to the other board and that appears to be working with just the AC adaptor so far.
However DCBATOUT is reading 20v (was 12v on the other board) is this not too high? 20V_DCBATOUT is at the same voltage as the AC adaptor....Leave a comment:
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No worries, thank you very much for your help with this - very insightful.
I have another identical board that is missing some mosfets (it had blown PU4403) and the ISL chip was also removed (I just checked that board and has no short on that 3V3 line).
I will transplant those components from this board and see if that one will work (and report back if so). (I also have another whole laptop coming with hinge damage I can use also).
Cheers, BenLeave a comment:
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Yeah, same resistance at that coil.
Tried on back of board and the only thing that warms up is...... U2401Leave a comment:
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Its only pulling 256ma (at 1V / 3A) so not enough to show anythingLeave a comment:
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Ok I will try that (I have thermal camera also)Leave a comment:
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Perhaps not - That takes in 3D3V_S5 and spits out 3D3V_S0Leave a comment:
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Its here i believe
[ATTACH=JSON]{"data-align":"none","data-size":"full","title":"image.png","data-attachmentid":3264361}[/ATTACH]Its here i believe
[ATTACH=JSON]{"data-align":"none","data-size":"full","title":"image.png","data-attachmentid":3264361}[/ATTACH]...Leave a comment:
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I certainly do - are we suggesting voltage injection?Leave a comment:
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4.7 ohm........Leave a comment:
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3D3V_S5 = 0.845v
5V_S5 = 4.95v
So does seem to be a partial short on 3.3v?...Leave a comment:
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Diode removed, still 156mvLeave a comment:
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Ok, thanks for the detailed explanation.
Measuring D4303 resistance :
Pin 2 negative / Pin 3 positive - 115k
Pin 1 negative / Pin 3 positive - 115k
Pin 2 positive / Pin 3 negative - 115k
Pin 1 positive / Pin 3 negative - 115k
i.e its just measuring R4302 / R4309 path to GND
Diode mode measures it correctly I believe - 0.685v voltage drop or OL the other way around - so doesn't look shorted on either diode.
[ATTACH=JSON]{"data-align":"none","data-size":"full","title":"image.png","data-attachmentid":3264337}[/ATTACH]...Leave a comment:
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Also to note these 3 things:
1) If plugging in the AC adaptor (after boards caps have discharged) - the charging light flickers rapidly for 2 or 3 seconds and then goes solid white
2) There is noticeable coil hum from PL4501 (3.3v)
3) The 3.3v voltage here is 0.85vLeave a comment:
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1) 156mv
2) 158mv
(sorry misread the question and measured resistance to start with)Leave a comment:
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1) 115k (at test point just above unpopulated/soldermasked r4317)
2) 2.25k (at r4305)Leave a comment:
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