Uncreative Labs

Joined: 29 Mar 2008 Posts: 51 Location: czech republic

Some time ago I got a XT class computer brand name Maxar 88L (made in Korea) Now I am trying to bring it back to life which appeared more complicated than I expected.
In general it switches on with one long beep, post test starts, it passes interrupt contrloler test, memory size test and stuck interrupt test, then it makes several blank lines on the screen (durig that time I can see short flash of hard drive led) then come 2 short beeps and that is all.

I tried that without harddrive controller inserted. Same bahavior, only fewer blank lines on screen. (harddrive is the only added card, graphics, i/o and fdd controller is integrated)

I suppose that the dip switch setting is wrong. The motherboard identificacion is something like HSII-MBD and there are 8 dip switches + 7 jumpers. All 8 dip switches are at ON position which I guess is incorrect.

Bellow are links for some high definition pictures (warning quite big images) of motherboard and post screen test.

http://www.svagr.info/other/maxar/index.html

Any suggestion for correct dip setting? Any other suggestion?

Update:

dip 4 to off position enables flopy drive (it seeks as it should), and I think, it tries to boot a short moment after seek (unsuccessfully) and then it beeps twice as usually

dip 6 has something to do with keyboard in off position I get message no keyboard present (even if it is plugged)

BTW: it has ps/2 keyboard connector but will modern ps/2 keyboard work with it? I do not have original keyboard.

I tried to replace floppy drive but still no luck:-(

Joined: 27 Jan 2007 Posts: 274 Location: USA

yea a modern ps2 kb works with it, but the windows keys and media keys are usless.

Joined: 03 Feb 2006 Posts: 488 Location: pennsylvanai

there are several things to know
switches control presence of absence of co-processor
amout of memory ( if the mb is really a 640k mb- these switched may be ignored)
the video mono, color 80x25, color 40x25, or none ( ega/vga) and number of floppies 1,2,3,4

If you have more than 2 floppies the hard drive gets moved up to d: or e:
there is no clock no hd settings, no serial or parallel ports.

try your oldest ( non tandy) keyboard. an AT or newer kn will NOT work. . many old kb have an at/xty switch , even hidden in the foot
some slightly newer kb are auto switch.
some at/xt switches may be backwards.

sometimes there are jumpers on the mb to set the meory ( chip type)

I will look up the settings, they are usually the same or similar to the ibm xt.

HINT: an old vga card will work if care is taken not to short the extra pins ( 16biyt card)
and switches are set at ega/none ( same setting)

with an ega card do NOT try to do mone graphics settings. monitor may die.
an ega card can be used with a cga monitor to get more color.

Joined: 03 Feb 2006 Posts: 488 Location: pennsylvanai

http://www.computercraft.com/docs/pcdip.shtml

here's the link

You will need a mfm or rll drive and controller
I can supplu settings. likely you will have to do a ll format
read the docs on this site. I sent them.
a 720k is ok
you can hook up a 1.44 drive and use dos 3.30
it will be seen as a 720k..
a 1.2m drive from an AT is totally useless.
ide xt cards were rare there are a few scsi but they MUST have a bios to boot the system.

If you find an old BIG "mfm" drive, look it up from a list. some esdi drives ( many from IBM ps/2's LOOK LIKE mfm drives (( 2 connectors) but are totally different) biggest drive was the seagate st-4096( 80m)
the ll formast on an at and an xt are different.

YOIU MUST ll fmt a drive with the correct controller.

Joined: 29 Mar 2008 Posts: 51 Location: czech republic

Thanks for all the hints friends, I will keep trying. In the worst case I will bring hardrive and controller from another XT computer to see if I can boot from harddrive at least. I know about need of correct combination of controller and harddrive but ll format is the last option, I wan't to save data on those old drives, who knows what treaseure can be there. (I have several drives and contolers, but don't know which belongs to which)

I used to be a big fan of XT class computers several years ago, but with lack of time I abandoded them for some time. Now I am back happy to see that uncreative labs is still alive.

I have on a place quite far from my home a Compaq Deskpro (the very first Compaq with 8086 cpu and math co.) which I hope it should work (but haven't tried 6 years). So I will borrow controller and harddrive from it and place it to this Maxar....

Joined: 03 Feb 2006 Posts: 488 Location: pennsylvanai

again thinks had not become as standard as thery did later
western digital made a wx1 card ( square) and a wx2 ( earlier)
some of the earler wx2 cards * 2/.3 length. had an undersized bios chip.
most of these chips were proprietary ( special) and were set for just one drive.

the newer the bios the better you are.
all boards, either wx1 or wx2 can use the same " super formatter bios"

drive table settings: there is a vertical row of chips.
the drive types are set ( 2 kinds or 10meg and 2 kinds or 20 meg) by the lower jumpers.
BUT if there is a jumper on only the top set, it is "free format" and if a mfm drive was formatted using
any of the older bios' the superformatter bios ( always a full-sized chip) will see the drive and it will work properly.
I think it is likely the wd-gen is close to the wx1 with the newer bios . but the jumpers may be absent and the bios will be soldered on.

If the drive came from some kind of AT or 286, the drive will not be accessible, It has to be in a at/286/386 withj the proper settiongs in cmos ( usually the physical heads and cyl. sectors was almost always 17.

on an at controller the wd 1003 or 1006 chipset is ok
the wd1007 chipset is for an esdi drive! do not use it.

early ibm xt';s used a xebec card which was quite didderent and a real dog.

Joined: 29 Mar 2008 Posts: 51 Location: czech republic

I am about to give up trying to bring it to life. The Dip switch is not same as on PC/XT.

Here is what I know until now:

- there is an extra switch outside for color/mono (on pc/xt is a dip switch)
- the floppy drive is 1,2M and it is functional and able to boot (in 486 computer)
- I found a working combination of contloller and MFM drive (booting one) but it does not boot in this computer, even does not print any info.
- The DIP switch 4 enables floppy and switch 7 disables onbard graphics card
- Spent several hours trying different dip combinations, no luck

What I still want to try:
- use a 1,44MB FDD with 720kB formatted floppy as someone suggested. That computer is not so old so I suppoe it supports HD floppy drives, but for sure.

- make sure that keyboard I have really works (I found old AT keyboard, disassembled, located the solder pad where the XT/AT switch used to be and modified the connection)

Joined: 29 Mar 2008 Posts: 51 Location: czech republic

So, finally I got it working Very Happy

To make long story short, my last problem was the keyboard Shocked

Obviously the opening an AT keyboard and disconnecting soldpads on place where the XT/AT switch used to be did not have needed efect. Now I have true XT keyboard and with some more playing with dip switches it boots from floppy and hardrive.

BTW: special thanks to wdegroot for a note about using a 16bit VGA card in 8bit slot as my hercules monitor died during testing, now I have a 19" LCD connected to this XT Smile

Joined: 03 Feb 2006 Posts: 488 Location: pennsylvanai

maybe VONAGE will let me call the czeck republic free?
any way if the video is integrated ( video chips on the mb) there may be a switch to select MONO/Hercules or color CGA. the other switch may select the video mode for CGA 80 x 25 or 40 x 25. the mono-herc is only 80 x 25. and most clones will be hrecules mono0-graphics compatible.
as said the memory switches, if the mb is a 640 mb, likely can be ignored.

don't use an older bios for the hd controller if you can avoid it. you may get "funny faces" and other strange sysmolds on the screen.
I remember one brand of my , that after a few years, would put "sparkes" and random stuff on the screen"
there is what they call " thermal ractheting"
meanun DIP chips and bios chips work loose
you can press down on them carefully, if they go "crunch" that means they were working loose

I may have said that a 720 or 1.44 drive can be used as a 360k or a 720k on most xt's
my brother-in-law's compuadd xt would support a 1.44. aviod a rll controller as that tend to be less dependable ( it will say 27x) a rll drive like a st-238 or st-277 can be used as a mfm drive,