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Posted by jakdedert on October 17, 2005, 10:31 am
Please log in for more thread options Ben Hutchings wrote:
>
>>Ben Hutchings wrote:
>>
>>>I have a second-hand Tecra 8000 on which the power socket for the AC
>>>adapter recently stopped working. I have verified that the AC adapter
>>>is producing the expected 15 V and the laptop continues to operate on
>>>battery power, so it is only the external power connection that is
>>>faulty. I disassembled the laptop, following instructions in the
>>>field service manual, and found that the connection between the power
>>>socket and the motherboard was cracked, so I resoldered it with the
>>>help of a friend.
>
> <snip>
>
>>If you're able to get it to connect by fiddling with the power
>>connector, then there's likely still a loose connection.
>
>
> By the time I posted, I wasn't able to make a connection at all.
>
>
>>Modern circuit boards contain many layers...IOW, they're like a number
>>of old-fashioned double-sided boards glued together. Where there is a
>>connection from one board to another, the hole is 'plated through' so
>>that anything soldered to that hole connects to each layer. When that
>>connection gets damaged physically, that plating is sometimes lost, so
>>that soldering to the top or bottom layer does not electrically connect
>>to the intervening layers.
>
>
> Yes. That's exactly what the problem was. (I actually worked this
> out by myself, but thanks anyway.)
>
>
>>You're only option--short of replacing the entire motherboard--is to
>>attempt to solder it again. Hopefully the solder will flow through to
>>the middle layers and make a good, solid connection.
>
>
> That didn't work for me, unfortunately.
>
> For the benefit of anyone else who runs into this problem, I'll
> explain my solution.
>
> When I inspected the board closely I realised I could see connections
> through the middle of the board to a square component near to the
> power socket. The top left pin connects to ground (socket shield)
> and the top right to +15 V (socket centre). I soldered a new wire on
> the outside of the board for the latter connection, and the laptop
> seems happy to run on external power again.
>
Lucky you. Good call. I'd have probably given up on it.
jak
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