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Some questions

Z

Zero Cool

Member
Joined
Mar 19, 2015
Messages
10
Hi all,

I got a box of old computer parts from my highschool's computer club. I slapped this together:

OS: DOS 5.0
Processor: Intel i486 DX2 (66mhz version)
RAM: 8mb, on 8 chips (1mb/chip)
Mother Board: Believe it might be Compaq but it only has a 5 pin DIN connector for keyboard (no mouse support)
Graphics Card: No clue. But it's the best one I have.
Sound Card: None :(
Bios: 1993 American Megatrends i386 (Like this http://thumbs1.ebaystatic.com/d/l225/m/mVjjBl0foRvRIVShaukwIXg.jpg)
3.5" Floppy
168mb hard drive

I proceeded to play the Blake Stone demo: https://www.gog.com/game/blake_stone_aliens_of_gold which requres a 486 processor with 2mb of ram only.

The problem is that the game plays at literally 1/4 frame/sec. I have to wait 4 seconds before anything happens. And even the menu screen is sluggish. I have been able to

My question is what can I add to the computer to make this game play?

***Important Note***
I don't know much about computers but I did notice that during the POST, the BIOS identified the processor as a 486 SX which is significantly slower than the DX2. Also I can put my finger on the processor when the game is playing and I feel little or no heat. As if there is a clock limiter or something. Can a bios be incompatible with later versions of CPUs? Playing around in the BIOS and following a guide to optimize the settings, I got the performance to spike during loading but not gameplay. Not sure what all this means.

Thanks for the responses in advance
Pictures to come
 
Compaq boards sometimes did things that were strange.

486SX is just the 486DX with the numerical coprocessor turned off. Even without the clock doubling running, at 33 MHz it should be more than sufficient.

My guesses are:
1) The SIMM installed only has 1 MB on it and you need at least a second SIMM to have enough memory. 8 megabit chips = 1 MB
2) You have a super budget VGA card with little RAM which will be too slow.
3) The Compaq motherboard is running in AT style 8 MHz compatibility mode, which could happen if you turned off the turbo button or incorrectly installed a cable on the motherboard.
4) Check that the jumpers match the chip you installed. No jumpers may mean that you are going to be stuck running at the slow speed Compaq set the system at.
 
Make sure L1 cache is enabled in the BIOS setup (often called "internal cache"). Then also check if L2 cache is installed on the mainboard. If not, it's probably a good idea to install it.
 
Here are some pictures that I took.

The first is a picture of the motherboard and then with my hand as comparison size.

WIN_20150813_180823.jpg
WIN_20150813_180841.jpg

This one is of the only DIN5 connector and all the RAM I have installed totaling 8mb (during the post, it checks the ram and it says I have something like 7684kb)

WIN_20150813_180904.jpg

The BIOS chip ( i made a mistake with the year -- it actually is from 1989 )

WIN_20150813_180928.jpg

My current Graphics card or VGA

WIN_20150813_181055.jpg

I'm not sure what brand they all are or the specs on any of them. Does this help?
 
Run some diagnostics that test system speed and report what they say. It really sounds like there may be a header for a "turbo" switch on that board that needs to be wired to a button or have a jumper placed over it.
 
g4ugm said:
Its an ISA video card. That will really slug the system
Click to expand...
Of course. What else would you expect in an ISA-based 486 mobo?

However, I too think the video card is the culprit. Not because it's ISA but because it's a dirty-cheap OAK Tech card. Try to get a Cirrus Logic 54xx or something, those are way faster.
 
I have never had anything but bad times and lousy performance out of an oak tech card as well, but my money would be on the turbo switch header being not plugged in or jumpered.
 
Doubt it's the video card. ISA is fast enough for 320x200 VGA. Yeah Oak cards were crappy but not that crappy.

Likely turbo switch or cache disabled.
 
The following link describes some of the AMI BIOS settings. The ones I would initially check include
AT BUS clock in case the divisor is too large which could make the VGA card run slow
Fast AT Cycle similar effects.
Shadow memory and Video Shadow ROM can also increase speed for the video card.

http://margo.student.utwente.nl/el/pc/bios/ami31.htm

Also, do you know which 486/66 it was? I have a hazy recollection that some of the later models had problems running on earlier motherboards.

Running a benchmark set to see what performance the CPU and video card are actually giving could provide clues as to what to check next.
 
I can't find any hints as to where the turbo button jumper is. And the internet has nothing about the motherboard. How is this graphics card?

WIN_20150813_181128.jpg

And could the make and model of the mobo be found during the POST?
 
krebizfan said:
Also, do you know which 486/66 it was? I have a hazy recollection that some of the later models had problems running on earlier motherboards.

Running a benchmark set to see what performance the CPU and video card are actually giving could provide clues as to what to check next.
Click to expand...

Thanks for the website on the BIOS.

The processor says A80486DX2-66. Not sure if this helps.
 
SomeGuy said:
Run some diagnostics that test system speed and report what they say. It really sounds like there may be a header for a "turbo" switch on that board that needs to be wired to a button or have a jumper placed over it.
Click to expand...

How do I run diagnostics tests on a fossil? Do you have recommended programs?

Thanks
 
Speedsys is used quite often over at Vogons http://www.vogons.org/viewtopic.php?t=33889 It's more a performance orientated x86 gaming site.

Old dinosaurs is what this forum is all about. I'd go with turbo jumper as well and possibly the L2 cache disabled. Look on the row off pins at the back of the board, behind the cpu. Those old boards where usually well labeled.
 
Last edited:
Zero Cool said:
I can't find any hints as to where the turbo button jumper is. And the internet has nothing about the motherboard. How is this graphics card?

View attachment 25878

And could the make and model of the mobo be found during the POST?
Click to expand...

The most likely place for motherboard contacts that could be hooked up to a turbo button would be a row of pins on one side of the motherboard. That set of pins would also include pins that would connect to the front panel for the power light and keylock. That is typical on 486 motherboards. I can't be sure how your motherboard works.
If you are lucky, the motherboard had text silkscreened which will point out which pins/jumpers need to be connected.

That should be a better video card.

Try recording the POST screens. Unlikely to find the breakthrough clue there but it can't hurt. Scrolling can be so fast sometimes that playing back a video is the only way to catch information.

A80486DX2-66 is a 5v CPU from 1992. I have one. It should be fast.
 
Last edited:
If can get a clear hi-res picture of the front of the motherboard near the CPU where those pins are, one of those should be the turbo switch and should be clearly marked with silk-screening on the board. Might say "turbo", might say "SPD", or "TB"... but they SHOULD all be marked. There should also be something like "Tb LED" or "Turbo LED" for connecting an LED to say if it's in turbo or not. Typically with those boards no connect is "slow" speed and shorted is turbo. Without a jumper or switch on the turbo that board could be feeding the processor anywhere from 6mhz to 16mhz instead of the 33, and that's your most likely problem.

That Oak video card could be a culprit, but I doubt it... but if you look closely at the oak you'll see that most of the contacts on the 16 bit part are in fact "no connect" because it's a 8 bit card that has the extra connectors on it for no good reason.

The trident 9000 card in your newer pic would be a far better choice for the system.

That actually looks like it might be an interesting motherboard as I THINK that brown slot is EISA, a somewhat rare (and often unreliable) attempt at making a 32 bit slot. I would advise NOT trying to run any 16 bit cards you have in that slot.

Could also be the jumper blocks are misconfigured, which is why tracking down the actual pinouts and jumper settings for that board is so important... It has some telltales of being an Asus board, but again a clear high-res top down picture where we could read all the silkscreening would tell us a lot about it.

It LOOKS like from the bottom corner near the CPU there's the traditional 5 pin keylock/power LED pins, then the speaker pins. If it holds to ASUS conventions of that time the next two pins would be reset switch, the next two the turbo switch, and the final two before the pair with a jumper on it being the turbo LED. See if those are labeled J10 (for the big one) down to J6. If so, try shorting J7.

You can short term just try shorting the pairs of two one after the other. If the machine restarts, well, there's your reset button. Nothing happens to the system speed, well that's probably the LED so don' t leave that shorted for too long. IF the system speeds up, well... bingo.

That final one that's jumpered? I got no clue. Might be CPU type select, but that still leaves that large jumper block on the other side near the expansion slots that could be used for processor clock, cpu timings, use DX2 or don't use it, cache size... Though the other set of jumpers up near the cache chips likely are for, well... yeah.
 
deathshadow said:
If can get a clear hi-res picture of the front of the motherboard near the CPU where those pins are, one of those should be the turbo switch and should be clearly marked with silk-screening on the board. Might say "turbo", might say "SPD", or "TB"... but they SHOULD all be marked. There should also be something like "Tb LED" or "Turbo LED" for connecting an LED to say if it's in turbo or not. Typically with those boards no connect is "slow" speed and shorted is turbo. Without a jumper or switch on the turbo that board could be feeding the processor anywhere from 6mhz to 16mhz instead of the 33, and that's your most likely problem.

That Oak video card could be a culprit, but I doubt it... but if you look closely at the oak you'll see that most of the contacts on the 16 bit part are in fact "no connect" because it's a 8 bit card that has the extra connectors on it for no good reason.

The trident 9000 card in your newer pic would be a far better choice for the system.

That actually looks like it might be an interesting motherboard as I THINK that brown slot is EISA, a somewhat rare (and often unreliable) attempt at making a 32 bit slot. I would advise NOT trying to run any 16 bit cards you have in that slot.

Could also be the jumper blocks are misconfigured, which is why tracking down the actual pinouts and jumper settings for that board is so important... It has some telltales of being an Asus board, but again a clear high-res top down picture where we could read all the silkscreening would tell us a lot about it.

It LOOKS like from the bottom corner near the CPU there's the traditional 5 pin keylock/power LED pins, then the speaker pins. If it holds to ASUS conventions of that time the next two pins would be reset switch, the next two the turbo switch, and the final two before the pair with a jumper on it being the turbo LED. See if those are labeled J10 (for the big one) down to J6. If so, try shorting J7.

You can short term just try shorting the pairs of two one after the other. If the machine restarts, well, there's your reset button. Nothing happens to the system speed, well that's probably the LED so don' t leave that shorted for too long. IF the system speeds up, well... bingo.

That final one that's jumpered? I got no clue. Might be CPU type select, but that still leaves that large jumper block on the other side near the expansion slots that could be used for processor clock, cpu timings, use DX2 or don't use it, cache size... Though the other set of jumpers up near the cache chips likely are for, well... yeah.
Click to expand...

Gee wiz!!!!

Thanks for all that wonderful information!!! I found my motherboard here: http://stason.org/TULARC/pc/motherboards/U/UNIDENTIFIED-486-BC3486UL.html#.VdDhMflViko

You were right! There is a TBSW and a TBLED near the CPU. I have jumpered the TBSW so it's permanently on. I hope this is ok because I don't have the actual switch, let alone a case to put this in. After reading the motherboard website, I decided to adjust some of the jumpers.

1) As for the DRAM configuration, when I got the board, there were chips missing that I later found in the box. Not sure if they were the right ones but I plugged them in and the system works.

2) I set the cache to 128K

3) I set the CPU speed to the 66MHz

4) I set the CPU type to 80486DX2

5) I don`t have a NPU so I left the jumper meaning (not installed)

6) Not sure what local bus slot selections are but I have 2 selections: Normal ISA cards or Local bus cards

And that's it for the jumpers.

My new questions would be, are these jumper configurations good? Can I leave the turbo switch on at all times? And for the DRAM, the website shows configurations for WinBond static RAM chips where they range from 32K to 4Mb of which I have the 32K ones. I was wondering if it is ok to leave all the slots filled even though it says to leave Bank 1 empty some times.

Thanks again for all the help.
 
Anonymous Coward said:
The brown slot is likely not EISA. Even mini-EISA boards had more than 1 slot. More than likely it's for local bus video. Even though the board has a UMC chipset, it might accept OPTi local bus VGA cards (like this one):

http://www.ebay.com/itm/Tseng-Labs-...-Rev-D-2148-/191647163295?hash=item2c9f0fa39f
Click to expand...

I have a 3 cards like this with the smaller pins but from what I remember, they don't work with the board. But I could be wrong because they fit on it.

Here they are:

The first is very similar if not identical to the one you found on ebay

WIN_20150817_153412.jpgWIN_20150817_153429.jpg

The second, I'm not sure

WIN_20150817_153452.jpgWIN_20150817_153459.jpg

And the third is on a different motherboard which I can't find right now (probably in the cupboard).
 
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