Thank you to all who responded to my plea for help regarding "toasted serial
ports on a sun 3/60". With the help of your messages, I have managed to get
my trusty old 3/60 back on its feet again. For those of you asked, heres
some information I found useful in repairing my own motherboard:
There are two rs-232 UARTS on the motherboard. One for the keyboard/mouse
and one for the two serial ports. On my machine these turned out to be
Zilog Z85C008PSC chips. Neither of these chips were "toasted" in the
lightning strike. These chips are socketed, and occupy U400 and U401.
In addition to the rs-232 chips, there are several driver chips that i'm
told typically get toasted first when lightning strikes. Many people
suggested I replace chips labeled "1488 and 1489". I never found any such
chips, but on the advice of an Apex computers tech, looked at some chips
labeled "26LS29" and "26LS32". These chips are right behind the serial ports
on the motherboard, and are labeled in the following way on the bottom of
the motherboard:
U409 (26LS29)
U411 (26LS29)
U406 (26LS32)
U413 (26LS32)
U407 (26LS32)
These chips are all soldered to the motherboard.
I removed all of these chips and replaced them (put sockets in first!)
This solved my troubles. I found the chips at a local micro electronics
store, and spent a grand total of $13.00 for chips and sockets.
If replacing these chips doesn't help matters, i'm told that the capacitors
near these chips (U412) are also prone to failure. Additionally, there is a
resistor pack for each port (R401 & R402) that can be suspect.
If none of this helps, I suppose the next step would be to replace to serial
chips themselves (U400 & U401). After that, you're on your own.
Unsoldering the soldered chips was not a trivial task, by the way, and if
you are not handy with a soldering iron, I would strongly suggest you
ask someone to do it for you. The copper traces in the vicinity of the
chips are thin and dense. One little slip, and..... Also I highly
reccomend that you put IC sockets in, so that next time lightning strikes,
you wont have to spend all afternoon hunched over your motherboard with
a sodering iron in hand.
I hope this helps some of you out there who mailed me asking for a summary.
Good Luck!
Jason Taubman
taubman@spot.colorado.edu
This archive was generated by hypermail 2.1.2 : Fri Sep 28 2001 - 23:08:09 CDT