Re the Simon's comment now that I am at a real keyboard and not a mobile phone I'll expand on my experiences.
I did socket those 4164s when I replaced them on the memory board. However it wasn't plain sailing for the very reason Simon mentions.
To replace the chips I clipped off the faulty IC's then extracted the pins by heating the solder pads from underneath and pulling the pins through. I then cleaned up residual solder from each hole with solder wick before fitting a socket. In one of the boards this went smoothly with no problems. On the second board however, I managed to damage two of the holes (or connections to them) when trying to clear out old solder. Once i finally cleared it I could see a bit of board damage under magnification and in one hole I could see I'd damaged a connecting track. I used thin connecting wire on the bottom of the board to bridge this break and to take the signal to where it should go.
Firing the board up I found it was still faulty!? A check of numbers showed it was the same column/row location. I knew it wasn't the chip so I figured I must have damaged something else. Eventually I found a connection to the adjacent RAM chip that wasn't being made, even though I couldn't see any obvious damaged tracks from the hole in question. Anyway, I wired in a bridging wire and the board now works as good as gold.
Anyway, as Simon says, resoldering these boards is not as easy as some. Certainly this is the first time I've had problems like this and I've done quite a few chip replacements now...mostly on single layer boards though..
Terry
Thanks. I replaced the chips before i read your email. As it was i did use sockets anyway so that was a lucky thing. Both boards work fine now. Great!
On 27/03/2011 10:08 PM, "simon" <simski_at_email.domain.hidden> wrote:
use a socket for the chip. resoldering double layer boards wrecks them a bit. even with a reflow station.
On 26 mrt 2011, at 23:15, Terry Stewart wrote:
> James,
>
>> Bit 0 maps to column 22 on the memory...
--
Groeten,
Simon
simski_at_email.domain.hidden
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