10 Mar
2002
10 Mar
'02
7:32 p.m.
Hello,
This is what I still have left. You pay shipping. Please reply off
list.
-IBM 68X3815 MFM hard drive controller from AT with original cables
-various mfm cables
-IBM PC Network Baseband Adpater/A (new in the box, Microchannel)
-Microchannel 4 port serial board (uses 16450 uart chips, but they are
replaceable, with cable)
-Intel 386dx-33 with glued on heatsink
-386dx compatible or upgrade chip, maybe Cyrix, I glued the heatsink on,
can't tell exactly what it is anymore :-)
-IBM keyboard cable for PC or XT, I think, maybe AT. It's not from a
Model M
-db25 to db9 convertor
-1/2 height faceplate for Seagate ST225
-IBM PC (5150) full height block off plate for unused second drive bay
-Fellows EMI glare shield for 14" to 15" monitor
-2 internal narrow scsi cable with external centronics connector (ask
for measurements)
-long 5 device narrow scsi cable (generic)
-3 two device narrow scsi cables
-1 two foot single device narrow scsi cable (folded for low cross
section)
-several vary short narrow scsi cables, some with connectors like you
would find on a card
Chad Fernandez
Michigan, USA
11 Mar
11 Mar
12:22 p.m.
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6:22 p.m.
The uart chips in this board are socketed, which makes them very easily
replaceable.
Chad Fernandez
Michigan, USA
Tony Duell wrote:
-Microchannel 4 port serial board (uses 16450
uart chips, but they are
replaceable, with cable)
I am just wondering what a non-replaceable 16450 chip is...
-tony
12 Mar
12 Mar
8:52 a.m.
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11:43 a.m.
I knew where you were going. It's just that for many, soldered in does
mean "non-replaceable", especially when the manufacturer uses those
chips that aren't recognizable as uarts. I don't know if everything is
on one chip or what, but I've seen some serial boards that only had a
very few chips and none looked like uarts to me. Also, surface mount
chips would be hard, since they are usually so small, although, I don't
think uarts are made that way, none that I've noticed any way.
Chad Fernandez
Michigan, USA
Tony Duell wrote:
The uart chips in this board are socketed, which makes them very easily
replaceable.
OK...
What I was commenting on (indirectly) is the idea that many PC-users have
that you _can't_ replace soldered-in chips, and you can't upgrade a 16450
to a 16550 if it's soldered in. Things like that. I don't want those sort
of ideas polluting this list :-)
-tony 
13 Mar
13 Mar
2:21 a.m.
At 05:43 PM 3/12/02 -0500, you wrote:
Also, surface mount
chips would be hard, since they are usually so small, although, I don't
think uarts are made that way, none that I've noticed any way.
Chad Fernandez
Michigan, USA
Yes they are; most recent i/o cards have everything (decode logic,
buffers, UARTs, even line drivers/receivers) integrated
in a small SMC chip. Toss and replace. I like old serial
cards with jumpers, even if they have soldered UARTS and
drivers, because I can fix them and upgrade them. Plus, they're
usually double-sided and easy to work with.
carlos.
11:51 a.m.
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1:52 p.m.
Yes, but even at 50 cents per hour, it's less costly to replace the board by
snagging one from a thrift store for $1 than to set about to repair one. The
thrift stores discard them by the dozens every day. So long as they are
cheaper to buy than to fix, I'd suggest one do that. It's only a matter of
time, however, before the CPU, memory, I/O and everything else you'd want will
be on a single device. That will help with the packaging, but won't do much
for maintainablity.
I just finished trying to buy some 3-volt logic, and find that everybody in
distribution's convinced that the only thing that is relevant any longer is
1.5-volt logic. I must have blinked ...
Dick
----- Original Message -----
From: "Tony Duell" <ard(a)p850ug1.demon.co.uk>
To: <classiccmp(a)classiccmp.org>
Sent: Wednesday, March 13, 2002 3:51 PM
Subject: Re: Free: older hardware, mainly PC
Painful, aren't they :-(
However, the original message said '16450 UARTs'. To me (as a hardware
hacker) that's a particular chip, often a 40 pin DIL device (although I
think a PLCC version exists). Single UART, no FIFO.
A multi-I/O chip (or even a dual UART) that happens to be
software-compatible with a 16450 is _not_ a 16450 to me.
At 05:43 PM 3/12/02 -0500, you wrote:
>Also, surface mount
>chips would be hard, since they are usually so small, although, I don't
>think uarts are made that way, none that I've noticed any way.
Oh yes, many common UARTs (and other serial chips) are available in PLCC
packages that can be surface-mounted. That does not make them
non-replaceable, though...
Chad Fernandez
Michigan, USA
Yes they are; most recent i/o cards have everything (decode logic,
buffers, UARTs, even line drivers/receivers) integrated
in a small SMC chip. Toss and replace. I like old serial cards with jumpers, even if they have soldered
UARTS and
drivers, because I can fix them and upgrade them. Plus, they're
usually double-sided and easy to work with.
Having replaced transistors on an irreplaceable, irrepairable [1] 16
layers PCB, I don't generally worry about normal multi-layer board any more.
[1] On-topic, very. The main ROM board from an HP9100B. The ROM assembly
is 4 boards linked by soldered-in pins. Address decoder, 2 sense
amplifiers, and the ROM itself. The last contains driver transistors and
an inductively-coupled matrix of tracks that form the bit pattern in the
ROM. If that ever fails there's no easy way to repair it. Fortunately all
I've had to do is replace the odd driver transistor.
-tony
6:46 a.m.
On Tue, 12 Mar 2002, Chad Fernandez wrote:
I knew where you were going. It's just that for
many, soldered in
does mean "non-replaceable", especially when the manufacturer uses
those chips that aren't recognizable as uarts. I don't know if
everything is on one chip or what, but I've seen some serial boards
that only had a very few chips and none looked like uarts to me.
Also, surface mount chips would be hard, since they are usually so
small, although, I don't think uarts are made that way, none that I've
noticed any way.
I've seen these boards myself, and they could be upgraded if you had some
of the dual 16550 uarts in the QFP package, and had the tools and patience
to replace them. Since 16550 cards are so plentiful, it just isn't worth
the trouble IMHO. For dual 16450/16550 uarts in a PLCC package, those are
not too much trouble to replace even if soldered directly to the board.
There is usually room for a PLCC socket too.
-Toth
6:51 a.m.
New subject: DEC TF867 in PA
I've sworn off eBay for a month, but noticed
this, expecially at the price.
It's a DSSI 6GB DLT, x 7 w/stacker/loader.
It's in PA and currently listing for $20.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2008068908
John A.
must not buy, must not buy
9:20 a.m.
New subject: DEC TF867 in PA
I've sworn off eBay for a month, but noticed
this, expecially at the price.
It's a DSSI 6GB DLT, x 7 w/stacker/loader.
It's in PA and currently listing for $20.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2008068908
I wanted to buy it for the loader, but they won't just pull
the loader unit out and send it. I'd have to pay $65/hour
(min. 1 hour) for someone to turn the key and pull the unit
out. Otherwise I'd have to pay shipping on the whole unit,
and that comes out to a lot, too.
--
Eric Dittman
dittman(a)dittman.net
Check out the DEC Enthusiasts Club at http://www.dittman.net/
8:56 a.m.
--- Chad Fernandez <fernande(a)internet1.net> wrote:
The uart chips in this board are socketed, which makes
them very easily
replaceable.
Tony Duell wrote:
> ...I am just wondering what a non-replaceable 16450 chip is...
>
> -tony
Awww... who needs sockets? With a long enough flat-bladed screwdriver,
they just pop right out of the board, don't they? If not, solid
whack with a 16 lb sledge can loosen them right up. For the most
stubborn chips, though, I recommend a quick dip in molten iron...
-ethan
P.S. for the humor impared -> :-)
P.P.S. solder shouldn't be a barrier to repair, but some stuff is
much easier than others. I dislike removing pins attached to
ground and power planes - sometimes it takes longer to free one of
those pins than the other 18 on the chip combined. Someone with
less experience might easily damage the pads or the PCB itself
trying to heat things up enough to be removed. As with most things,
though, good tools and practice on replaceable items is essential
before tackling tough jobs. I can see how people can be intimidated
by a job that starts with firing up the iron.
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10:29 a.m.
At 11:56 AM 3/13/02 -0800, Ethan wrote:
P.P.S. solder shouldn't be a barrier to repair, but some stuff is
much easier than others. I dislike removing pins attached to
ground and power planes - sometimes it takes longer to free one of
those pins than the other 18 on the chip combined. Someone with
less experience might easily damage the pads or the PCB itself
trying to heat things up enough to be removed. As with most things,
though, good tools and practice on replaceable items is essential
before tackling tough jobs. I can see how people can be intimidated
by a job that starts with firing up the iron.
If you want be able to repair stuff, a decent temperature controlled
iron it the best investment that you'll ever make!
Joe
4:06 p.m.
On Wed, 13 Mar 2002, Ethan Dicks wrote:
trying to heat things up enough to be removed. As
with most things,
though, good tools and practice on replaceable items is essential
before tackling tough jobs. I can see how people can be intimidated
by a job that starts with firing up the iron.
I am going to make an offer to the list, since it's been helpful to me for
so long. I am willing to de-solder and re-solder parts for classic
computer stuff if you send them to me and pay return postage. I have all
three of: good equipment, time, and experience. I de-solder through-hole
parts with a professional vacuum de-soldering station and I can do
surface-mount parts with pins on two opposite sides with hot tweezers,
pretty much no reasonable limit on number of pins- I have lots of tips. I
don't have a hot-air rework station for removing quads but I can
do two things there: my usual method is to cut the chip out (I have a
special method to prevent lifting lands) or if the PCB isn't densely
populated I have a hot air gun. I do soldering by hand. I solder
size-0201 capacitors at work occasionally (imagine a part that occupies
.05 cubic millimeter- it is smaller than the ball in a ball-point
pen) and so even the 200+ pin quads on today's motherboards aren't too
challenging.
If anyone has anything they need soldered or de-soldered let me know. My
offer of free labor stands indefinitely.
Richard Schauer
rws(a)enteract.com
near Chicago, Illinois
11:45 a.m.
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8168
days inactive
8170
days old
18 comments
11 participants
participants (11)
-
allain＠panix.com -
ard＠p850ug1.demon.co.uk -
carlos_murillo＠epm.net.co -
dittman＠dittman.net -
edick＠idcomm.com -
erd_6502＠yahoo.com -
fernande＠internet1.net -
geoffr＠zipcon.net -
rigdonj＠cfl.rr.com -
rws＠enteract.com -
tothwolf＠concentric.net