3 Apr
2011
3 Apr
'11
6:16 p.m.
On Sun, 3 Apr 2011, Alexandre Souza - Listas wrote:
Heh. Thanks anyway - it's the thought that counts :-). You've just
described the ordeal I went through fixing my Amiga 4000. That
motherboard is the opposite end of the quality spectrum from the Lisa.
Very thin cladding, wimpy solder masking. There were two or three
obviously-eaten traces around the battery site, but unfortunately that
wasn't the extent of it.
Ended up removing the RTC clock latch, the two adjacent LS166 chips (mouse
and game port interface), the Ricoh RTC chip, the F257 memory bus driver
and a couple of electrolytic caps. Things were chewed enough around the
clock latch that pads lifted despite my taking great care. Took a full
saturday afternoon to rebuild with 30g Kynar wire. Found two more traces
eaten - one under the Ricoh chip and one under the first LS166.
It's not real pretty now, but it does work 100%!
The real casualties in the Lisa are the bus connectors. I'm going to
replace the one on the CRT cage first, since it's a ribbon-cable crimp on
type. The memory card connectors are a bit flakey, but I don't want to
tackle that just yet since it works most of the time. More important to
get the keyboard and floppy disk operational and the connector is the
common denominator there.
Still curious what folks' experiences are in using a hot-air reflow tool
to soften up through-lead components from behind for removal.
Steve
--
I cleaned
things up enough to get the self-test and startup to run. The
DB-9F mouse connector is effectively destroyed from the battery
electrolyte. If I wiggle the connector the mouse is operational, though. A
good sign. Not looking forward to pulling the old DB9 right-angle
connector from the motherboard... This one is too far gone for cleaning
and will definitely need to be replaced.
Steven, when I get some device with this level of trouble, I usually
disassemble EVERYTHING in the affected area, clean it up with grit pad until
I can see only cooper and start to retin the traces with common solder, and
repair broken traces with very thin wire-up wire. Replace everything with NEW
parts. Usually it works at first and does not break up after. A throught
clean-up is primordial for having no problems on the future.
I'm sorry I'm so far away (I live in Brazil). I'd love to help you on this
matter.