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you guys remember computer reset right
the giant warehouse of old computers in
dallas it was like an archaeological dig
well ever since it closed to the public
things have changed a lot
there's been a group of volunteers
working over the last year to remove
trash and reorganize a place so you can
actually walk through it now without
worry of
dying in an avalanche of heavy sharp
steel objects
oh and they replaced all the lights now
so you no longer need to bring a
flashlight with you just to see where
you're going
of course this place is clear on the
opposite side of dallas for me which is
a one hour drive just to get there
and then another hour to get home
needless to say i don't make the trip
over there unless i have a good reason
anyway one of the volunteers called me a
few weeks ago and said they found
something i might be interested in doing
a video on
and apparently there are five of them in
these boxes they found in the back room
and so i agreed and they loaded it right
up into my car for me
and now that i've got it home in my
garage let's take it out and have a look
so what we have here is an ibm 7496
executive workstation
it's apparently quite rare if you google
for that you won't find anything at all
except maybe this video but at the time
i'm making this video as you can see
there's just
nothing to be found so let's see what we
can find out about this thing
let's open the keyboard well you can
tell this has been in the box for a very
long time
oh well it appears to be a standard ibm
model m
keyboard manufactured in 1988 and
we'll just plug the cable in here it
looks like if you want to access the
porch you have to open this door
now one thing i want to show you is that
you can stick your finger right through
here so i think that's where they want
you to run the cables
i'd also like to point out that the
monitor while integrated onto the case
actually plugs into the back like a
regular monitor plugging in the power
cable turned out to be more difficult
than i thought
no matter what angle i tried i struggled
to get it to fit i suspect it was
designed with a right angle plug in mine
however i don't have one of those handy
anyway i eventually got one in there and
of course to power it on we have to find
the power switch
this certainly could be the switch to
power on the whole system but
there's this front cover here that's
locked and i can't see what's in there
i went back to the original box and
found the key was taped to the top piece
of foam
and let's see if that works and it does
but the only thing behind the door is a
floppy drive incidentally i've never
seen a cardboard transport protector for
a three and a half inch floppy drive
before
very neat okay so i'm ready to power
this thing on
it's possible it's been sitting in that
box in excess of 30 years so
you know who knows what'll happen
well i hear the fan running
and we did get a post beep so that's
promising you might be tempted to say
the monitor isn't working but uh watch
what happens when i power it off
that effect suggests the monitor part is
working fine
so i guess the next step is to take it
apart maybe there'll be something i can
repair
every screw in this system is one of
those annoying flat tip screws
i'd like to know who thought these were
a good idea
well the bottom comes off easily enough
but there's this three prong connector
going to the monitor most likely for the
switch and for powering the monitor
itself
looking at the board it reminds me a lot
of a ps2 model 30 or something like that
there are some interesting oddities like
the sticker over the top of the isa slot
saying do not use this slot
i suspect it's because there's only two
slots on the rear of the case so no
opening for the third card
i want to get a look at the rest of the
board so i'm going to remove the power
supply
and it looks like a standard ibm at
power connector there
and next i'll remove the drive bracket
here some interesting things of note
it appears to have possibly an ide
connector but there's no room to mount a
hard drive perhaps they plan to ship it
with either a hard drive or a floppy but
not both
anyway the cpu is an intel 8086 and
there is an empty socket for a floating
point unit next to it
i see 64k of video ram and being it has
a vga port on the back
that means it probably uses mcga video
which was more or less unique to the ibm
ps2 models 25 and 30
or at least so we thought of course that
makes sense being the model 30 came out
in 1987 which appears to be the same
year this system was manufactured
ideally i'd like to power this thing on
and try with a regular monitor but
there's no power switch anywhere to be
found
so it looks like i need to figure out
how this cable works one thing i
immediately noticed is that when i put
my meter in continuity mode
on pins one and three and then flick the
power switch you can see that it's a
direct
short so i think this is how the switch
passes power to the power supply
so here's my plan i'm going to bend up
this paper clip and make a jumper to
take the place of the switch
so i'll just poke that in there like so
all right so i get the power cord hooked
up but
i'm actually going to flip the power on
the power strip and we'll
see if it blows up
yeah that's not good okay that's
probably not good uh this caused the
lights in the room to flicker and i can
actually see a spark inside the power
supply i'll show you again in slow
motion if you look right in this area
you'll see a flash coming not only from
the paper clip in the connector but
from the bottom of the power supply so i
guess that didn't work so
i'll take that out and i guess i'll
connect it back to the monitor and see
if it still works at least as well as it
did before
so here goes that is a door now
all right so now i'm going to take the
power supply back out take it apart and
see if there's hopefully a fuse in there
that blew because uh hopefully that's
all it was
oh you've got to be kidding me the power
supply uses some security screws which i
don't have the tool for at the moment
and rather than order one and wait
several days i'm gonna do the next best
thing
now i'm not going to chop the screws off
but i'm going to chop the sides of the
head off so that it's more square
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so like this i should be able to use
some pliers and rotate it some
and there we go one down and three more
to go
so i got the cover off and i see the
fuse
that thing's in there tight let me pry
that out of there
it sort of looks blown but i can't tell
for sure so i'll test it with my meter
and yep it's blown
uh by the way while we're inside of this
thing check out this fan i've never seen
one like this in a computer power supply
anyway i took a trip to the hardware
store to see if i could find a
replacement fuse and
sure enough i think this is an exact
match good
you know it's stuff like this that makes
these projects take forever i mean i've
already wasted basically a whole day on
this power supply problem oh
and by the way when i go to put this
thing back together i will not be using
those horrendous screws instead i'll
just use regular screws as the threading
is standard
that way if me or anyone else needs to
get back inside in the future
it won't be such a pain okay so here we
go again
i'm going to try to power this thing up
here's that mysterious cable i don't
understand the wiring on obviously
and guess what it's still dead i spent
the next two days troubleshooting the
power supply trying to figure out what
else was burned out and
simply couldn't figure it out needless
to say there's no chance of finding a
service manual for this thing because
the almighty google
doesn't even seem to be aware that the
machine even exists but even if it did
the service manual would probably say to
replace the power supply as one whole
unit
so the likelihood of fixing this
computer is looking more and more bleak
it was already broke and i seem to have
made it even worse
so a couple of weeks later i went back
to computer reset and the volunteers
were kind enough to let me test out the
other machines they had there
these were all sealed in their boxes so
the question is did they arrive at
computer reset in working condition and
have just failed due to age or did they
wind up here in the first place because
they were defective
powering these on may help provide that
answer david here
yep he has the same name as me was kind
enough to pull these out and check them
so here goes the second one and well it
does pretty much the same thing the
first one did
the screen comes on and in this dark
environment you can even see the raster
but
no video so here comes unit number three
and it too did the exact same thing
starting to see a pattern here so on to
unit number four
oh what the heck it appears the roofed
league during last night's rainstorm and
soaked this box well it's it's dry
should probably power it on see if we
can test it
okay so uh here goes unit number
oh my four the one box that had water
damage
actually has a system that posts
unfortunately upon closer inspection the
video is garbled
it looks like bad video ram but at least
this gives me something to go on
so this is the most promising unit so
far but we thought we'd go ahead and
pull the last one out just to be sure
this one actually looks just a bit
different i noticed the monitors of a
different style
our theory is that this one has a color
monitor and the other ones were
monochrome
it has a ps2 look to it for sure
unfortunately as you can see
it has the same problem the rest of them
have no video and no post beeps
on the bright side it did have the
manual which i'm going to take with me
it might be handy
okay so we have the partially working
unit back at home and i guess it's time
to see if i can make any progress with
it
i tried to see if it would boot any sort
of dos but it doesn't
just get this screen and by the way i've
seen this screen before on a properly
working ibm
and while similar i think this
workstation is just a bit different
animation
interestingly it will boot to basic in
rom and
i can play around a bit there are
actually two issues i can see first i
noticed that any characters starting
with the lowercase p
and after is corrupt so looking at an
ascii chart
this basically means that everything
highlighted here will display correctly
anything past that is corrupt this would
make a lot more sense of being a ram
chip or a broken trace or something if
the corruption started one line further
down because that would split it right
down the middle
indicating a problem with bit 7 but
since it's not like that it
makes no sense at all i suspect it could
be a problem with the video generation
chip or the character rom
but there's a second problem it's even
more perplexing every other row of text
on the screen is shifted over by what
appears to be 16 characters to the right
i was hoping i could get this thing to
boot to a dos disk and then maybe i
could try something in graphics mode and
that would tell me if it was a character
rom problem or not
okay so time to disassemble this one and
by the way i had tried booting this from
a floppy disk but had no luck um i think
there's a problem with the disk drive so
i removed the drive and swapped it with
the drive in the other system
now these appear to be the same drive
mechanisms that were used in ibm ps2
systems
i tried a 720k ms-dos disk and after
pressing f1 it does attempt to read the
disk but
ultimately doesn't boot from it i took
one of the drives apart to see if they
were gummed up or had broken belts but i
couldn't find anything wrong
then i thought i'd try an xt ide card to
see if maybe i could boot from that
however
not surprisingly it didn't work the ps2
line of the same era
are known for having a bios that doesn't
support option roms on expansion cards
i took it over to my friend kevin's
house he makes and sells these little
adapters that allow you to use a
standard floppy drive in a ps2 style
system
so i thought maybe we could try one of
those and it fits in there just fine
much like before the light comes on and
the drive spins but it doesn't seem to
want to boot
so just for the heck of it kevin took a
known working drive from an ibm ps2 and
put it in there
it fits perfectly by the way but still
didn't work
we also tried swapping the ram modules
not that we expected this to work but
people would ask about it if we didn't
at least try i also tried swapping the
bios rom chips from the other machine
but it made no change in behavior
and we thought about desoldering and
swapping out the 64k video ram here but
we were both convinced by this point
that the video ram probably wasn't the
culprit
and well guys we've come to the end of
the road i've been working on this for a
week now and it's just time to move on
but there's something i want to point
out about these computers these
could possibly be prototypes and there
are three reasons why i think that's
possible
first of all is what i mentioned before
this just sheer lack of any
documentation to be found on google
anywhere
the second reason is because i cannot
find any serial numbers on these
machines
anywhere on the inside on the outside on
the back of the bottom they just they
don't have any
the third reason is because some of the
parts in here have handwritten part
numbers on them
like this floppy drive cable connector
here for example
that's something you typically don't see
on a mass-produced product from ibm so
it is unfortunate that i was not able to
get one to work but
i think they are more or less identical
in function to something like an ibm ps2
model 30
so you know you could use that as a
reference to see what they might be like
if they were working because those are
well-known computers
and if these are prototypes and they're
still the mystery of how they wound up
at computer reset and the question is
did they show up there 30 years ago in
working condition and they just
deteriorated from age
or were they broken when they showed up
there in the first place
i will say that all of the systems that
we took out of the box look essentially
brand new i mean there's no signs of
wear there's no
signs of usage there's no you know scuff
marks there's no dents there's no
no dirty things dirty fingerprints or
anything like that on them so again
big mystery there and we may never know
the story behind them but i hope you've
at least enjoyed having a look at this
piece of forgotten computing history
i have told the volunteers at computer
reset that if they find anything else
interesting to go ahead and give me a
call and maybe i'll do a review on that
as well
but that's it for the moment so stick
around for the next episode and
thanks for watching
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you