Hi Phil
If you know a part is bad and you want to remove it
from the bard with the least damage, clip the leads
close to the part and then remove the leads, individually,
with a pair of tweezers/iron. Always use a temperature
controlled iron set to the point that a clean tip
will melt the solder of the joint in about 10 to 15 seconds.
Even really cheap PC board can be reworked if one
uses some care in methods. I don't recommend using solder
wick. Many do well with it but it tends to get stuck
to traces if not overly heated and will lift traces.
If you use a solder sucker, don't use a small one.
Use one with as big a bore and stroke as you can find.
Dwight
>From: "Philip Pemberton" <philpem_at_dsl.pipex.com>
>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.
> In my opinion, the Jupiter Ace is one of the most appallingly-made
>machines I've ever tried to repair. Heck, the Commodore 64 was bad, but at
>least the pads were easy enough to desolder. It looks to me like Jupiter
>Cantab's PCB designer was either *VERY* inexperienced or just wanted to
make
>sure that no-one could fix an Ace if it failed. It's also beginning to look
>like the ROMs are stuffed, but that shouldn't be too hard to sort out --
>I've just bid on some 2532 EPROMs on eBay from someone in Austria.
> 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.
>
>Later.
>--
>Phil.
>philpem_at_dsl.pipex.com
>http://www.philpem.dsl.pipex.com/
>
>
Received on Tue Dec 10 2002 - 15:36:01 GMT