In a message dated 98-03-28 09:24:11 EST, you write:
<< > <1) Does this really work? I thought you couldn't over clock a true AT?
> < (This particular motherboard is a "256/512 K System Board" with
> < piggy-backed RAM chips. It has lots of "ECOs" on the pin side of
> < the board. I don't know if my other one does, too. Note: ECO =
> < Engineering Change Order.) >>
its my understanding that the original AT bios dated ~1984 would work ok if
the machine was overclocked. later versions of the AT bios were fixed so
overclocking will give you a post failure for your efforts. of course, my type
1 AT had an aftermarket bios so i didnt have that problem, and i could also
specify custom drive types.
david
<Obviously this is meant to over clock the 286, with the rotary switch
<allowing increasing the clock frequency until the 286 fails.
Overclocking another retrorevionistpc idea.
No most likely it allowed you to buy the fastest 286 and clock it at it's
native speed.
<1) Does this really work? I thought you couldn't over clock a true AT?
< (This particular motherboard is a "256/512 K System Board" with
< piggy-backed RAM chips. It has lots of "ECOs" on the pin side of
< the board. I don't know if my other one does, too. Note: ECO =
< Engineering Change Order.)
The AT might go a little faster, at some point the DRAM timing goes flakey
and otehr things start to get cranky.
That's especially true of the ISA cards!
<2) Would increasing the 286-6 to a 286-8,10,12 increase the frequency
< at which it could reliably run? I have a PGA 286-8, but I'm not
< sure there are faster PGA 286s?
There are it went all the way to 12 or 16mhz. I have a LCC version thats
12 and the PS/2m50s I have are 10mhz.
<3) Any software needed? (The ROMs appear to be the same as on my other
< machine.)
None but the rams may get unhappy of pushed to fast (data takes time to
get out).
Allison
> I received today a Diamond Computer Systems Trackstar e
>Apple ][ emulator board for my PC. Does anyone have any instructions for
this
>thing??
>
Yes. I email them to you separately.
-- Kirk
I found an IBM PC/AT (for spare parts for another recently acquired one)
with a small card placed in between one power supply lead to the
motherboard. It also has a lead clipped to the motherboard, presumably
to insert modified clock frequency to the 286.
On the board it says "Megahertz Corp (c) 1986 286-2 REV 4". The board
bolts to the back of the chassis and has one button (reset) and two
switches (6MHz-Turbo and rotary 8-9-10-11-12).
Obviously this is meant to over clock the 286, with the rotary switch
allowing increasing the clock frequency until the 286 fails.
So, this suggests these questions:
1) Does this really work? I thought you couldn't over clock a true AT?
(This particular motherboard is a "256/512 K System Board" with
piggy-backed RAM chips. It has lots of "ECOs" on the pin side of
the board. I don't know if my other one does, too. Note: ECO =
Engineering Change Order.)
2) Would increasing the 286-6 to a 286-8,10,12 increase the frequency
at which it could reliably run? I have a PGA 286-8, but I'm not
sure there are faster PGA 286s?
3) Any software needed? (The ROMs appear to be the same as on my other
machine.)
Thanks for any information anyone can shed on this.
Dave
Thought someone in the group might be interested. As usual, if you
are discovered, I will deny any knowledge of your existence.
>We have an OLD Data General One Laptop from 1983!!!!
>
>We would like to sell it!
>It works well, has a modem, and an HP Think Jet Printer!
>
>No reasonable offer will be refused!
>
>-------
>PLEASE DO NOT REPLY TO THIS:
>Send all inquires to: mldat(a)the-pentagon.com
>
>Thank you!
>
-Bill Richman
bill_r(a)inetnebr.com
http://incolor.inetnebr.com/bill_r
(Home of the COSMAC Elf Simulator!)
Although directed at Tim or Allison (as the two other DEC-savvy folk on
here), this one's wide open. I got the attached E-mail from a visitor to my
web site. Unfortunately, I'm not that familiar with the hardware he's
gotten hold of.
Can someone else get in touch with him and give him a nudge in the right
direction? Thanks!
-=-=- <snip> -=-=-
>From: MHarvey863 <MHarvey863(a)aol.com>
>Date: Fri, 27 Mar 1998 22:32:25 EST
>To: kyrrin(a)jps.net
>Subject: Please help me
>X-Mailer: AOL 3.0.i for Windows sub 161
>X-MIME-Autoconverted: from quoted-printable to 8bit by dry.jps.net id
TAA11206
>
>Hi there.
>
>I need to beg for help. My department at university has just offloaded its
>junk on me & I've got half a dozen VAXstation 2000's, a VAXServer 3550 and a
>MicroVAX 3500. Your's is the only site that gives refernce to any of these
and
>Digital wanted to charge me ?100 before they'ed even give me the time of
day.
>
>Can you help me with any VAX info or machine info. I believe they all work,
>but the only compatible monitor I had blew up just before I aquired them.
I've
>got the odd three-way cable to connect the mouse, keyboard & monitor and I
>would ideally like to restore the client/server setup that they were in
before
>they were junked.
>
>Thanks very much
>
>Matt Harvey
>
>
>
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Bruce Lane, Sysop, The Dragon's Cave BBS (Fidonet 1:343/272)
(Hamateur: WD6EOS) (E-mail: kyrrin(a)jps.net)
"Our science can only describe an object, event, or living thing in our own
human terms. It cannot, in any way, define any of them..."
> > Your guesses seem correct about the function of the
> connectors, but I'm
> > not so sure about the mapping of the 26-pin connector --
> they seem like
> > they might be reversed from what I would expect. Here are
> a few I buzzed:
The 1488 and 1489 are level shifters (+/-12Vdc to/from +5Vdc) for an
RS-232 interface. This is consistent with an RS-232 port. Remember,
the 26 pin connector will be wired to match whatever serial cable came
with the board, they aren't all the same.
Jack
The other day I picked up a Commodore 128D. [Along with a Timex
Sinclaire 1000 with some sort of module hanging off of it that I'm not
sure about, Also a Commodore 1541 Floppy all for $25 at a Pawn Shop)
Anyhow, I plugged in the C128 and I get only a black screen. I checked
the fuses and notice one had been blown. I replaced it and still only
had a black screen and a newly blown fuse. I'm going to do some checks
on the power supply to see if I can fix the fuse blowing and hopefully
the black screen.
I also have picked up an Atari 520ST with the external floppy drive - no
power supplies or cables. My thinking is that I can always build those
if I need to. What all of this is leading to is - Does anyone know of
any good resources for pinouts, schematics, etc on the old PC's? Also,
does the black screen on the C128D ring any bells for anyone?
Thanks!
Mike
