Leo 286 PC dip switches

[Amigaz]

Last time I went to get rid of my trash I found an old 12mhz 286 PC from an obscure company called Leo (Computers) I started a reviving process imidiately because I plan to use it for old games up to circa 1990 to avoid speed problems etc
The machine was unexpanded with RAM so I filled the four 30pin simm sockets with 4 1mb simm's but I now get some memory config errors on my bootscreen and can't change the mem settings in BIOS
I think I need to change the DIP switches but since I don't have a manual I'm not sure how to set them so I turned to this forum where I know people have great knowledge in old computers so I would appreciate if someone could give me some hints, please

Here's some pics from the machine:

http://imageupload.com/out.php/i71430_P1010242.JPG

http://imageupload.com/out.php/i71431_P1010245.JPG

http://imageupload.com/out.php/i71432_P1010239.JPG

 

[Jorg]

I'd just say one of your simms is faulty.

Nice, an Oak87 vga card

 

[Amigaz]

I'd just say one of your simms is faulty.

Nice, an Oak87 vga card

really? gonna try another set then

So you don't think I have to tell the computer with the dip switches how much mem that installed? I mean it passes the BIOs mem tests...the error message looks like it doesn't like the type/size of memory that's installed

The Oak card looks really ancient but it isn't soon to be replaced with a Cirrus Logic 5424 or Tseng Labs 4000 card

 

[kb2syd]

Some of these older machines do not like "weird" varients of RAM. They require simple 9 chip parity ram simms. Some also can't handle mixed varieties of RAM. Also, I think some of the early 286 machines only took 256k simms, but on this I very well could be mistaken.

It looks like a pretty generic motherboard. Any other markings on the motherboard? Anything match up with:
http://members.tripod.com/~dainesn/th99/m/m286_t.htm

Kelly

 

[modem7]

On the first screen shot is, "MEMORY PARITY ERROR AT 01:0000:0000 FOUND AA55 EXPECTED AA55"

My interpretation:
The power-on-self-test (POST) wrote AA55 to the first memory address, then read back AA55 (that's good), but the circuitry that checks the parity bit detected a problem. Then the POST presumably aborted that sub test.
So the motherboard expects RAM modules that have a parity bit, but it sounds like you've inserted non-parity RAM. One of the DIP switches may disable parity checking (sometimes it is a jumper).

4352K extended RAM found. That suggests to me that the motherboard accepts 1MB modules, but not necessarily of the type you've inserted. As KY2SYS wrote, these old boards are finicky about the RAM that can be used. The user manual usually specifies exactly what type of RAM can be used.

and can't change the mem settings in BIOS

So in that second screen shot, please confirm that you mean that you can't arrow down to the "0" against "EXTENDED MEMORY", then type in "4352", then arrow to some other figure, then press the F10 key to save the changes.

 

[Amigaz]

On the first screen shot is, "MEMORY PARITY ERROR AT 01:0000:0000 FOUND AA55 EXPECTED AA55"

My interpretation:
The power-on-self-test (POST) wrote AA55 to the first memory address, then read back AA55 (that's good), but the circuitry that checks the parity bit detected a problem. Then the POST presumably aborted that sub test.
So the motherboard expects RAM modules that have a parity bit, but it sounds like you've inserted non-parity RAM. One of the DIP switches may disable parity checking (sometimes it is a jumper).

4352K extended RAM found. That suggests to me that the motherboard accepts 1MB modules, but not necessarily of the type you've inserted. As KY2SYS wrote, these old boards are finicky about the RAM that can be used. The user manual usually specifies exactly what type of RAM can be used.


So in that second screen shot, please confirm that you mean that you can't arrow down to the "0" against "EXTENDED MEMORY", then type in "4352", then arrow to some other figure, then press the F10 key to save the changes.

A kind soul at vogons.zetafleet.com pointed me to this location: http://stason.org/TULARC/pc/motherboards/U/UNIDENTIFIED-286-SUNTAC-286P.html

Looks like my motherboard alright except that I don't have the IDE/Floppy connector on my board, there's a dip switch in this documentation which will change the parity setting so I hope it wil help

And yes, I cannot change the "0" in the memory settings