On Dec 10, 20:03, Philip Pemberton wrote:
> Hi all,
> Well, it looks like I've finally destroyed the Ace. I've just spent
the
> past hour trying to desolder the dead RAMs and buffers from the Ace's
main
> PCB. Unfortunately it looks like the board was designed to self-destruct
> when anyone tried to repair it.
> The pads appear to have been designed to peel off on the application
of
> heat, they're less than 5 mils around the hole (what do you think that
> means?) and they don't even seem to be through-hole plated. The tin
plating
> was applied straight on top of oxidised copper - I've had to retin some
pads
> and tracks courtesy of that major screwup.
Machines like that were designed to keep the cost as low as possible, and
repairability often wasn't a consideration.
On things like that, I often don't even try to rescue any suspect ICs or
even passives, just cut them off close to the PCB with a very fine pair of
sidecutters, and then desolder the stub of pin.
> Does anyone know how I could rescue this machine? It looks like the
RAMs
> are definetly fried, along with some of the logic as well. Font RAM and
> Video RAM are still not being loaded on startup so the output of the
video
> generator is still 100% noise, however it *is* changing when the machine
is
> powered off and then back on again. I'm shotgunning all the RAMs (there's
> only six of them) and the bus muxes.
> Has anyone here either repaired one of these machines or got a spare
Ace
> to sell me? I've got a proper PSU now, with only one connector (the jack
> plug the Ace uses), so I can say with near absolute certainty that the
same
> mistake will not occur again.
First thing is to make sure anything you remove is replaced with a good
quality socket, and if necessary that you can repair any damaged tracks
with stripped wirewrap wire or similar. How adept are you with a
soldering iron? I used to do this sort of thing for a living, and I'm not
too far away if you want someone to take a look at it.
Did you get the 2114s and Z80 I sent you? They should have arrived this
morning.
--
Pete Peter Turnbull
Network Manager
University of York
Received on Tue Dec 10 2002 - 15:22:01 GMT