My Acer 486 correctly identifies a 486DX4-100, but with a 5x86 it identifies it as DX2-80. It benchmarks faster compared to the DX4-100 however so it's working, just the POST message is a bit off 😀

I believe that more boards have support for the Intel DX4-100. There is also the overdrive DX4-100 which runs on 5V.

Hm, Robin,

you mean these two pieces?

I had a look at the datasheet of lm2576t ADJ - you actulally migth be right - I'll test it this evening, with the settings for DX4 (anyway, this CPU is supposed to work at 3.3V).

Thanks

Found no time today for tests. Hope tomorrow will be less stressful day.

So, people, you think it will be safe to run both the CPUS from the pic above, at 3.3V?

A DX4 120 is a respectable chip to have in a 486 system provided there is support in the BIOS for it. Your riser has a single 16 bit ISA and one VL-bus slot. In a low profile case, a limted number of expansion slots is to be expected but it does force you to choose which expansion cards are the most important to you for that system. If you have onboard sound and video and can live with them, that makes it a bit easier but if not then you will have some hard choices to make. 4 RAM slots was pretty much standard for consumer grade PC's at that time, but you really should find some cache chips to fill those empty sockets. It doesn't make a tremendous difference, but in a 486 every little bit helps.

Space Cowboy wrote:

Found no time today for tests. Hope tomorrow will be less stressful day.

So, people, you think it will be safe to run both the CPUS from the pic above, at 3.3V?

Yes those things are Voltage regulators..

If you have them both it would be automatic voltage settings.

I have here a free computer technologie 486F38X motherboard, and that board also uses with automatic voltage setting. Just put the processor in and only set the right settings on the board.
If you dont have lucky, the board support till 100mhz.. Then a correct bios upgrade is your only hope to support more..

Thanks Robin, in 12 hours I'll know 😀

The PC is: Unisys CWV 4002. I couldn't find BIOS upgrade, and it's a phoenix bios, unfortunately (I would rather prefer if it was AWARD). So ... let's hope the Am 5x86 will work.

Sliderider, I have 5 cache chips delivered in a few days (I hope), so I hope for at least 128K cache.

What do you think is the maximum RAM I could put in? And only FPM, I believe.

Hm, on the good side, I have my DX4-120 discovered as a DX4-100. It means, the board won't give more than 33x3, but thats OK.

The bad side is, that I have some memory issues - although I know I tried single sided Kingston 16MB SIMMS, (and single sided modules have never ever been a good idea - don't know whose wicked mind has born the idea to cut production expenses in that nasty manner). Anyway, I can't run more than 2x16MB single sided. When I try to put SIMMs in all 4 slots, I get black screen.

You also can try that 5x86 processor.. The processor will work if its a working one.. But cant give you guarantee that the bios will regonize that processor.. Then it would also run on 100mhz speed.
The bad of this motherboard is that it cant run on 40mhz system clock.. So then there are no options for 120mhz processors

For setting up the 5x86 processor.. You need to have 33 system bus by 2x muliplier = 66 mhz system clock.. Then you need to set the DX4 muliplier also on 2x.. (because is a quad clocked processor) = 132Mhz.. if it would regonize it would be a 133mhz clocked one . AS AMD 5x86-133 P75.

Yes the 5x86 interprets a 2x multiplier as 4x to be more compatible. So setting the motherboard clock to 33 and multiplier to 2x should get it going.

On my 486 the BIOS reports it as a 486DX2-80, but performance is what it should be when benchmarking.

While still waiting for my cache and VRAM chips, this morning, I was helping my father to clear a wagon at our villa, so imagine my surprise, when I discovered a box of old motherboards (most of them socket 7, nothing special - one of them ATX though), some ISA cards, and that little fellow:

I was so sure I have thrown it away years ago (it was my ex-gf's PC that I upgraded), cause I DO remember how I left the case besides the trashcan, and I extracted the DX4-120 to keep it. The case was damn heavy - probably made out of german WW2 helmets 😀

But it seems I've kept the board. It's been somewhat poorly stored - temperatures -15C to +30C, but no direct sunlight and no direct water (moisture, probably).

Can you help me identify the board, and if someone has a manual for these jumpers, it will be of great help, cause they make no sense to me (except for the voltage one, and the ones that have descprition onboard)

There is an isncription on the board: lite on 20V0 9548-11, but I got no reasonable results when I googled it. (SIMMs, most of the results)

It's really strange to me, that the board does not support 5V.

Plus, I found my old ESS card 😀

Now ... this is a board, that suits better to a 486 revival. Although it's small form factor, I suppose BIOS will recognize my am5x86-133. And if it runs at 4x40 ...

Unfortunately, I keep no DIN keyboards. Any adaters DIN<->PS2? And how can I run a mouse today with this board? (all controllers are gone in trash long time ago). Have no serial mouse, so ... any Plug-and-Play I/O controllers with PS2?

Yes there are DIN <> PS/2 keyboard adapters. I use them for my 386 and 486 gear.

You will have to either get a serial mouse or motherboards with PS/2 connector. My top is to get an OEM PC like HP or Acer. They all have PS/2 ports. On motherboards it's tricky and expensive. There is an Asus motherboard with PS/2 on eBay Germany, but costs a lot of money.

We're working on the PS/2 mouse "problem". 😎 That board doesn't appear to have a removable keyboard controller though.

Mau1wurf1977 wrote:

Yes there are DIN <> PS/2 keyboard adapters. I use them for my 386 and 486 gear.

You will have to either get a serial mouse or motherboards with PS/2 connector. My top is to get an OEM PC like HP or Acer. They all have PS/2 ports. On motherboards it's tricky and expensive. There is an Asus motherboard with PS/2 on eBay Germany, but costs a lot of money.

Hm, I have the OEM PC, but it lacks PCI Slots. And has only 2 ISA. And it's max is 33x3 (prbably 33x4 with the Am5x86).

It's not about the speed, rather about the controll and upgradeability. OEM's run rock stable, but have less options to play with.

Then where can I find a new serial mouse (optical, may be 😀 )?

For keyboard - this probably. I'll have to combine it with some of my GF's shoes orders 😀
http://www.amazon.com/SF-Cable-MiniDin6-Femal … pd_sim_sbs_pc_4

I have forgot to write it: there is an isncription on the board: lite on 20V0 9548-11, but I got no reasonable results when I googled it. (SIMMs, most of the results)

I'll power it on this evening, cause I'm curious.

I'd just stick with the OEM you have. Otherwise you will be spending a LOT of money.

A DX2-66 is fine. What are you going to do with the project?

For more speed get an IntelDX4 overdrive. Works with 5V and very compatible.

[edit] (shortened it a bit, goin for the real questions) [/edit]

Well ... Mau1wurf1977 - some gaming, I beleive. No much, but ... yeah, I want to see some of the games I played back then, on a hardware from this era. I know that DX2-66 is OK for gaming - I have one of them (came with the OEM). But I would rather prefer to see a 486 platform maxed out at the top of it's performance. Running a Windows 98SE (before I put DOS + win 95 on it).

Ahaha, who would believe ... 😀

Smallest 486 MOBO I've seen

But I think the cache on my board should be real - as long as full size sockets + chips are installed.

Update:

Hm, the board is either dead, or I'm missing some jumpers know-how.

Tried with two S3 videocards - no signal output.

Any ideas? I have no ISA videocard to try with.

I'll change capacitors - there are about 20 of them. But it will take a week or so (gotta find some time at work)

Meanwhile, I'll get back to the original topic-starter - the OEM unisys. It does not have the "flavor"of the other board, but is packed with PS2 KB and mouse.

It is most likely the ADI's mainboard TK8881 FA20
http://www.elhvb.com/mboards/adi/tk8881/TK8881man.html

Definitively not the PCChips version as your board appears to have real cache. Also your board have two capacitors in the bottom right corner, just like the board I linked to.

One thing, that comes to mind ... you know, I actually used the AT PSU of the OEM PC, that was the original topic starter (I don't have other AT PSU's at home). It's a 110W of unknown to me brand (tiger blah-blah).

I believe, there is no way that this PSU could be modified and won't feed a regular AT board?

BIOS an L2 cache chips cleaned and reinserted, coin battery changed, I'll test it in two hours to see if it starts. If not - I'll go for the caps replacement.

I spent so many hours in reading, that I now started to wonder, why the hell did I have to start this 486 refurbishing, while my socket 7 is getting dust in the wardrobe 😀

edit: board is still not working ... hm, I'm gonna get the iron this weekend

Space Cowboy wrote:

I spent so many hours in reading, that I now started to wonder, why the hell did I have to start this 486 refurbishing, while my socket 7 is getting dust in the wardrobe 😀

Yea 486 suck the life out of you 😀

S7 restores some sanity again.

As to my other 486, I have some cache related questions.

http://www.image-share.com/ijpg-2334-14.html