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| Author |
Message |
rcurl
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Obsolete Computer Parts
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Mar 24 01:36 UTC 1993 |
Obsolete computers still live. Sometimes they need parts.
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| 36 responses total. |
rcurl
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response 1 of 36:
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Mar 24 01:41 UTC 1993 |
I use a True Blue XT at my office (they've abandonded PCs - gone all
Mac - but I find it handy for people that wander in off the street
with the "wrong" OS), which has 256K RAM built in and 256K on an AST
"Mega-whatsis-II" board, whose clock has fritzed. I need those 128K
more the XT allows, so am looking for either a used AST board with
384K aboard, or the "Piggyback" board that goes on it, with 128K.
Anyone have a dusty ziploc on their shelf with one of these?
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tsty
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response 2 of 36:
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Mar 24 04:29 UTC 1993 |
try entering thhis in the classified conf, also.
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klaus
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response 3 of 36:
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Mar 24 13:25 UTC 1993 |
Rane. I have some information on putting 640K on the mother board of
a genuine IBM XT. As I recall, all you need is a hand full of 256K
chips (Jemmie as em for $0.60 ea), some common TTL chip, and add a jumper
to the bottom of the board. Easy. I did it to one of mine and it worked
fine! Let me know if you want to persue this further.
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klaus
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response 4 of 36:
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Mar 24 13:27 UTC 1993 |
Oh, I forgot. I also have a 348K board I'll sell you. Mail me if your
interested.
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rcurl
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response 5 of 36:
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Apr 8 13:24 UTC 1993 |
I'm still considering my options on the above upgrade. I could try klaus'
board, but it doesn't have a clock or serial port (which are on the
AST board in the machine (though the clock is fried)): therefore I'm
also looking for a serial/clock board, to put the "package" together.
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rcurl
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response 6 of 36:
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May 29 05:04 UTC 1993 |
Brief synopsis of instructional lesson in memory upgrade: n8nxf's (nee
klaus) 384K board works fine (thank you!); installed "cheap" serial+
parallel+clock+floppy-drive board for serial+clock, but my A: drive
became unworkable; tried all resident floppy driver board switches for
secondary ROM-BIOS and I/O locations, but NG; pulled humongous (48 pin)
controller chip on I/O board, and it worked! - except now had environment
space overflow; MS-DOS manual *useless* for expanding environment space;
had to go home, so computer spread across my office (found env space
expansion command in Jamsa's DOS); typical afternoon booting the PC until
it, and I, were blue.
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tsty
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response 7 of 36:
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Jun 2 07:00 UTC 1993 |
Blue, huh, hmmmmmmmmmmmmm.
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rcurl
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response 8 of 36:
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Jun 2 14:19 UTC 1993 |
Yes, blue: an XT. Well, to continue the saga: found how to expand
environment with shell=c:\command.com /p e:256 in config.sys (but
wondered if there is another way), so that's OK; tried to use COM2,
but no go; clock all screwed up!; that "humongous..chip" must do
something else; must remove "cheap" serial+parallel+clock+floppy-drive
board and find a serial+clock board. Wow. I'm really saving money.
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n8nxf
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response 9 of 36:
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Jun 3 12:10 UTC 1993 |
Isn't there a jumper that'll allow you to deselect the floppy port?
(Or just tie the interupt for the floppy inactive. Cut the foil to
the buss first though, so you don't tie down the whole bus!)
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rcurl
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response 10 of 36:
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Jun 3 14:17 UTC 1993 |
No jumpers refer to controller. How does one "tie the interrupt for
the floppy inactive"? What is the "foil to the buss" that should be
cut? Actually, there is something weird about this board. It has three
chip sockets (two small, one big), which do not have chips. I initially
thought it might be a rework, but I find that I cannot "locate" either
COM2 or LPT2 with Norton SI, with the jumpers set so they shold be
enabled. Is it likely that a new board would come with some empty sockets?
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n8nxf
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response 11 of 36:
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Jun 4 12:57 UTC 1993 |
Interrupt IRQ 7 is used for the floppy controller. Your card plugs
into one of several edge connector sockets known as the XT bus. On
this bus, pin B21 is IRQ 7. On your card there is a trace which
connects to this point when the card is pluged into the bus. Cut
this trace, but so it can be repaired should I be wrong.
That should do it. The floppy controller on the brd. should be kaput.
I suspect that you don't have a COM2 chips on your board! You need
to plug a UART (same as the one already on the board) and a couple
of quad line drivers (also same as those on the brd. for COM 1.
could be 1488 and 1489?)
(Forget what I said about tieing this and that inactive. I was
thinking of something else.... Give it a try.)
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goose
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response 12 of 36:
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Jun 4 13:35 UTC 1993 |
I thought 7 was used for LPT2, and 6 was the floppy controller.
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rcurl
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response 13 of 36:
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Jun 4 15:02 UTC 1993 |
I pulled the board and called the vendor. They'll take it back. I
ordered separate clock and serial boards for total $$ slightly less
than the composite board. But add trip and $$ UPS for return. I was
tempted to start to muck with the composite board "because its there",
but, enough already. However, for the aficiandos, the shmanual (that's
a sh--ty manual) says IRQ7 is LPT1, but doesn't say which is the
controller interrupt (though IRQ6 is available). The shmanual says
nothing about the controller (the board also has "timer 1" and
"timer 2", with nothing in the shmanual what the difference is or
why one would want one or the other). This must all have something to
do with the board having been made in China, and the chips are variously
labelled "singapore", "malaysia", "thailand", "goldstar" (sounds like
a cruise ship to southeast asia ;-)).
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mju
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response 14 of 36:
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Jun 4 21:51 UTC 1993 |
Handy PC IRQ table:
IRQ Use
--- -------------------
0 Timer 0
1 Keyboard
2 unused (PC) or cascade to secondary 8259 (AT)
3 COM2 (if installed)
4 COM1
5 LPT2 (if installed)
6 Floppy drive
7 LPT1
8 CMOS real-time clock timer
9 unused, wired to old IRQ2 line on system bus
10 unused
11 unused
12 unused
13 unused
14 Hard drive
15 unused
Note that interrupts 8-15 are only present on AT-class machines, and
are cascaded through to the secondary 8259 interrupt controller.
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rcurl
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response 15 of 36:
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Jun 5 05:43 UTC 1993 |
Bad board shipped back; new boards arrived today and installed. Everything
works fine! End of stirring XT upgrade saga. Thanks to all those that
helped, commented, made witty observations. Now...I'm about to tackle
adding 2 M expanded memory to my Zenith 151. I am sure I will be back 8-).
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tsty
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response 16 of 36:
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Jun 6 05:46 UTC 1993 |
REALLY?!?!?!?!?!?!????????
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rcurl
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response 17 of 36:
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Jun 7 05:21 UTC 1993 |
Yup. What's wrong with that?
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tsty
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response 18 of 36:
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Jun 7 08:33 UTC 1993 |
REinforcing your "8-)" ...
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rcurl
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response 19 of 36:
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Jun 7 13:32 UTC 1993 |
Got it!
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goose
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response 20 of 36:
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Jun 7 22:35 UTC 1993 |
Whoops I meant LPT1 in #12.
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rcurl
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response 21 of 36:
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Jun 11 06:42 UTC 1993 |
(Footnote to XT upgrade, or, "it never ends": with new memory, ports and
clock, LOTUS123 wouldn't work. After a few more hours......found it was
the time display the clock board put in the corner where the MODE display
is located. Disabled clock board time display....sigh.)
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tsty
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response 22 of 36:
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Jun 12 07:09 UTC 1993 |
Aren't there selectable corners for those things?
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rcurl
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response 23 of 36:
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Jun 12 07:21 UTC 1993 |
There would be on a Mac, where the clock is in the menu bar, and cannot
interfer with applications. However on that XT - I don't know of a way
to move the Lotus indicators, and the clock software has no options. One
way around this would be to start Lotus from a .bat file, which first
dismounted the display, which is a TSR. Is there a generic way to do
that? (The clock software doesn't have - or at least tell one about -
a command to remove the display.)
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awijaya
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response 24 of 36:
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Aug 23 13:26 UTC 1997 |
<< Goldstar >> Hello Rane, most Intel CPU now are made in Malysia.
Seagate manufactured their drives in Singapore + Thailand.
Quantum + Maxtor also have giant factories in Singapore.
Goldstar is the old name for giant Korean company that manufacture
most DRAM/memory chips today. They change their name to LG
(From Lucky Goldstar). Best regards (AW)
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