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This anything like it ? :D
http://www.386page.com/systems/ibm/pc/mobo-small.jpg
http://www.386page.com/systems/ibm/p...plus-small.jpg
Quote:
This is one of the most common upgrades for the pc/xt. It's a ast six pack plus. It added up to 384k of ram / a real time clock (RTC) / And 3 i/o ports. A serial and parallel port was on another bracket but I could not use it as my system was full.
104456's suggestion sounds likely, if the system is actually an XT class 386, rather than an AT that happens to have XT in its model number, then it truly is a dinosaur.
An XT can even have all of its memory on an expansion card on the ISA bus (or the CPU as well for that matter). If this is the situation, there are a number of possibilities. There could be 512K on the mainboard and an expansion board gone faulty, an individual memory chip could have failed, or a switch that sets memory size may have developed a bad contact.
Sure, that's what I thought: the memory is incorporated on the expansion boards!
I actually had a couple of older hand-me-down PC's prior to this one with only 256 KB memory--including an original IBM PC clone, in fact!--which I ran right up until their dying breaths! I even managed to find a perfect match expansion card to replace a moribund one!
When I took one of those PCs to a technician to have a hard drive installed into its empty drive slot, I was told that particular "Jurassic Park" size was no longer made--which is why I got this 386 XT second-hand with its already built-in hard drive! 640 KB was "monster memory" back then!
So I guess what I'll have to do is bring my 386 XT into the shop and see if it's worth repairing and even upgrading. Or, since there are plenty of "computer graveyard" places where I can clamber through mountains of dusty, grimy relics, perhaps I'll pick up a couple of matching boards for only a few dollars--perhaps even for free! "Gold" is often discovered in these places!
Then, of course, no sooner will I have plugged them in than something else will go awry! Just like an old car, right? :-)
Looks to me like the BIOS or CMOS setup has the memory between 512KB and 1024 KB disabled. For example the line which reads:
Bank 2/3 DRAM Type : Disabled
should be displayed as
Bank 2/3 DRAM Type : Enabled
Exactly.Quote:
Originally Posted by Robert M
Wish I knew how to enable it. The toggle function doesn't seem to work.
I'll spend a little more time with it and see if I discover anything. Otherwise, the important thing is that I've transfered all my valuable files onto 3 1/2 disks, so if the 386 XT blows up in a cloud of smoke, at least I can say I had my fun with it--while it lasted!
BOOM! (cough, cough!) :D
You can always pick up another on an auction site for 20 bucks or so :rolleyes: :D
Eureka! (somewhat!)
Remember I wasn't able to toggle between the 1 and 0, enable and disable option in the XCMOS setup screens? (Remember, I bought this PC second-hand and have no original user guide).
Well, by holding the SHIFT key while pressing the PgUp/PgDn key, I can switch back and forth between most of those options--but not all!
For some reason, other BIOS lines aren't accessible, despite my reading various websites such as: http://margo.student.utwente.nl/el/pc/bios/ami31.htm
and others.
I cannot, for example, on the boot up System Configuration screen, I cannot alter the "Base Memory Size" line from the way it originally was at 640 KB from what it shows now at 512 KB
Nor can I alter the "Ext. Memory Size" line to its original 3072 KB to what is now 0 KB.
Nor can I alter the "Bank 2/3 DRAM Type" line from the original "Disabled" to what I want it to show as "Enabled"--although some sites say to leave it disabled. Not sure why.
Even though I successfully toggled the Bus Clock to its original CLK2IN/2 and altered the "Bank 0/1 DRAM W/S wait state to 0 (zero) from the 1 (one) I've been stuck with, and similarly the "Bank 2/3 DRAM W/S wait state to 0 (zero) from the 1 (one), when I exit and reboot as required, the "clicker" still ends at 512 KB, and no amount of cursing will make it do otherwise.
Still, I am encouraged. I may yet unravel the 386 XT's secrets!
Note some of these "BIOS help" pages get into excrutiating detail. They also bring up the matter of the battery on the expansion board--which can be disabled or bypassed to perform certain functions. Not sure if that would solve my problem though.
I may end up getting one of those boards you mentioned somewhere. Too bad, but I've learned that most of our local "computer graveyards" have disappeared. Think of the billions of computer scrap buried in landfills around the globe!
See if you can change the memory interleave from enabled to disabled.
Then see if you can re-enable the Bank 2/3.
That computer probably does not accept memory on 30 pins SIMMS or 72 pin DIMMS.
It seems to have four 256KB memory chips on the motherboard or a similar arrangement for a total of one megabyte or RAM memory.
There doesn't seem to be any toggling access to those two lines. They're not even shown in the XCMOS setup screen, whereas the "Bank 0/1 DRAM...", and "CLK2IN/2" lines, etc. are toggable.Quote:
Originally Posted by Robert M
Even the headings within the XCMOS screen under Memory Configuration as follows:
BANK ENABLED/DISABLED
0 ENABLED
1 DISABLED
2 DISABLED
3 DISABLED
...cannot be highlighted with the arrow or page up/down keys nor the shift key combination. They are out of reach. I suppose there's a good reason.
I even utilized the DEBUG code entry to bypass any existing password requirement to alter the CMOS clock, devices, etc. I re-entered the correct data, rebooted, and nothing untoward happened.
Note that I never activated any such password of my own, nor was I aware that any password had been inserted by the PC's previous owner--whoever he or she may have been, so my DEBUG entry may have been benign.
So everything that is toggable I've toggled! (I better change my username to...oh, forget it! :p :D
Assuming the little battery inside is dead, if I were to obtain a new expansion board with a new battery on it, would that alone re-expand my memory from 512 to 640?
As some of you gentlemen have said, it could be a few things. Anyway, no sense in beating a dead horse.
If the memory controller cannot physically access memory beyond 512K, then options needing upper memory cannot be enabled. Equally, for bank interleave with a 386sx, banks 0 to 4 will all have to be populated. As the system originally ID'd 4MB total memory, it was probably set up as 4x1M. Unless there's something like a DIPswitch on the board to set memory size, and it's developed tarnished contacts so giving a wrong memory size, I'd suspect a faulty memory chip.
A bit of a pity really, as a board with a NEAT chipset is actually one you could optimise well for DOS use, memory-wise.
Nothing lasts forever.Quote:
Originally Posted by Platypus
It's too easy to get bogged down and even obsessed with all of this stuff, and it's worse when the end-user has little or no experience tinkering with computers to begin with.
Then there's the issue of obsolete and hard-to-find parts--although in my case I do believe the expansion boards I would need are still available, though maybe only online and rather pricey.
No wonder the trend in electronic appliances has been to throw everything "old" in the garbage and upgrade, but I do think it's pretty ridiculous that equipment only a few years old--such as my laptop--are not worth the expense to repair. It's become a racket, and consumers are often too willing to put up with it.
As for the 386 XT: it's a relic, to be sure, but as long as it holds up, I'll continue to use it until the inevitable day arrives when I'll have no choice but to replace both it and the laptop with one, brand-new desktop.
What is the brand name and model of the computer?
Have you searched for CMOS setup information on the internet?
Have you tried the CTRL key held with the page up key or page down?
If there is a memory expansion board installed, maybe removing temporarily will allow the CMOS option for the second 512KB to be enabled...but I'm not sure of this. I would also try to set the WS (wait state) to zero, and then retry the bank.
A couple of things on this problem:
CMOS Battery? is ther one and is it one of those NiCad type.. you could have corrision on the board from leaked chemicals from the battery. the damage from this sort of thing can be terminal.. My reasonong here is period of down time of the machine, followed by the reset of the clock..
Next is the CMOS Itself, having had to reset the time, it is probable that other hardware setting have become corrupted. From experience a good reset of the cmos (a bit hard to advise in this case due to no manuals) could be all we need. You will find that you will have to go over ALL the settings
Back to the CMOS battery... is there any areas of Blue - or Blue Green "Dust" or fine crystal growth?..
There is no brand name as such. It's a clone.
I've changed the CMOS date, time, etc., and everything else there is to change with the exception of certain lines--mentioned in my previous posts--which are innaccessible for whatever reason. Yes, I reset the Wait State to 0.
Fortunately, I made a printout of the BIOS screen way back when I purchased this PC, and I've already made the necessary corrections to conform to that original screen as far as I am able.
I didn't notice any discolouration nor leakage on any board the last time I opened it up. Not sure exactly where the battery was located, either.
I'll get around to it at some point. Certainly I'll post here any significant results
--such as they may be.
All of your suggestions are much appreciated.
You can also try pressing the turbo button and retry for the needed CMOS setting.