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Abit AB-PB4 for 486 build

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First post, by Nahkri

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I found a Abit AB-PB4 rev1.2 with a intel 486sx-33mhz,for under 10 euros.
Is this a good board to start a 486 build?I never had or builded a 486 and wan't to give it a try.
I like that this board has coin battery and pci slots.
Will it support the Amd 5x86 and Cyrix 5x86?

Reply 1 of 54, by Skyscraper

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Its a very late 486 board so yes its a very interesting motherboard. It supports pretty much every CPU that fits in the socket.

I bought an untested rev 1.3 for.. more than 10 euros, so far I have not been able to get it to post. Sometime in the future when I have bought a BIOS programmer I will be interested in getting a copy of your BIOS as I did not find a reliaable source online (I did find a BIOS file from a shady source though).

New PC: i9 12900K @5GHz all cores @1.2v. MSI PRO Z690-A. 32GB DDR4 3600 CL14. 3070Ti.
Old PC: Dual Xeon X5690@4.6GHz, EVGA SR-2, 48GB DDR3R@2000MHz, Intel X25-M. GTX 980ti.
Older PC: K6-3+ 400@600MHz, PC-Chips M577, 256MB SDRAM, AWE64, Voodoo Banshee.

Reply 2 of 54, by Nahkri

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I didn't buy the board yet,wasn't sure it's a good choice plus it's also untested,here's a pic from the seller.

pic_zpsroiffqmg.jpg

I managed to find a manual and a bios file but they both have the .exe extension,can't open it on my windows 7 x64 pc so atm can't check what they are,if it's a valid bios file i'll let u know.

Does this mb work with regular edo ram ?

Reply 3 of 54, by Skyscraper

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Yes it supports regular EDO ram 😀

New PC: i9 12900K @5GHz all cores @1.2v. MSI PRO Z690-A. 32GB DDR4 3600 CL14. 3070Ti.
Old PC: Dual Xeon X5690@4.6GHz, EVGA SR-2, 48GB DDR3R@2000MHz, Intel X25-M. GTX 980ti.
Older PC: K6-3+ 400@600MHz, PC-Chips M577, 256MB SDRAM, AWE64, Voodoo Banshee.

Reply 5 of 54, by Nahkri

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I found another 486 board this 1 http://motherboards.mbarron.net/models/486pci/pt432b.htm it also has pci slots,it's based on a umc chipset,it has the posibility to use 512kb of cache,the Abit board only has 256k,the manual also shows a ps/2 connector altough i can't find one on the motherboard,so not sure if it had ps/2 or not and also has a barrel batery instead of coin.
The mb for sale had only 5 scokets from 9 populated with cache memory,how much cache does that mean?
Which 1 would be the better choice?

Reply 7 of 54, by chinny22

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I've got the Abit board and can confirm its a nice reliable board. You can read about it here
Another 486 being built

As a 486 Starter board its pretty good. PCI works well, only thing I don't like is lack of PS2 mouse.
Don't know about the other board

Reply 8 of 54, by Nahkri

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In short:
Abit has-has 256k cache not sure if the cache memory is in slots so it can be removed and swapped with larger size cache sticks.
-ali chipset
-coin baterry
-missing ps/2 mouse

Pine tech motherboard-not sure how much cache it has,from the sellers picture,only 5 cache slots,from 9 in total are filled rest are empty,so dont't know the amount of cache.
-umc chipset
-ps/2 mouse
-but has a barrel battery,which from the low res seller picture,look ok no leakage.

Tbh i would choose the second board,if it weren't for the barrel batery.

Reply 9 of 54, by kanecvr

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@Nahkri - if you're not going to buy the board, I'd like to get it. The only 486 boards I own are a FIC 486-VIP-IO witch is a little weird, kind of slow and VERY PICKY about RAM. It will only take standard and FPM SIMMS - In-line and EDO don't work on it so I'm stuck with 12MB... my other 486 MB is a PINE designed for a POS system - it has no PS/2 and is damaged by leaked acid so BIOS settings get corrupted all the time and COM ports don't work at all. Besides these, I have another defective 486-VIP-IO (previous owner put the CPU in backwards since the CPU power traces are fried) and a weird early ISA only socket 2 mb with a 486-SX on it and 30 pin SIMM slots...

So if you're not going to buy it, tell me and I'll look it up on OLX...

Reply 10 of 54, by Nahkri

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http://olx.ro/oferta/placa-baza-veche-cu-proc … html#0a77b67fde

U can get it,but seller doesn't know if it works,so u could pick up another 1 with problems.

Reply 12 of 54, by bbg

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kanecvr wrote:

Thanks for the link, maybe I'll get lucky!

Too late! Got it yesterday... 😈
It was a long struggle... 😵 All jumpers were placed on the front panel connectors 😠 , one made of course a short between the 5V rail and ground, after applying the juice... 😊
After hunting down the (in)famous .exe manual, and placing the jumpers correctly, replacing the drained lithium coin, plugging in an ISA ET4k, and two 8MB FPM DIMMs, it went somewhat smoother: the i486SX33 finally came to life. 😀
Trying an i486DX2-66, lying around, was a no-go - maybe a bad CPU. 😒
Replacing the ISA VGA card with a PCI Stealth64, got the dreaded video-RAM error beeps. 😐 Tried a bunch of other PCI VGA cards: no joy. 😢
A bothering limit of the on-board F0 BIOS is 2GB HDD. Older 386s had no problem with bigger drives... 🤣
Time to hunt a newer BIOS, got the F2 lingering on the net, including the (in)famous .exe (actually a SFX LHA).
Time to extract the BIOS chip from it's socket and plug it in the programmer. Auto ID the "flash" chip, and got an 1Mbit EPROM (M27C1001). 😕
Where should the plug'n-pray ESCD tables be stored? It needs a Flash chip... Someone cut corners in the production run. 😠
Got an 1Mbit Flash (29F001), rotting in a drawer, and burned it with the F2 file. Plugged it back in the M/B, and voila, BIOS checksum error, enter Setup, modify the settings, correctly autodetect the 8GB CF, save, and reboot: ... "Updating ESCD", and smoothly booting to DOS. 😎
Time for the PCI VGA card... no more error beeps, and it works 😲
Let's try again the DX2... surprise, it works too 😲 But it quickly gets hot, time for a heatsink... and a well deserved rest.

Reply 13 of 54, by GL1zdA

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I did some benchmarks a while ago, and this board had the best memory speeds in Speedsys out of all my 486 boards - it seems the FinALI is really the fastest chipset.

getquake.gif | InfoWorld/PC Magazine Indices

Reply 16 of 54, by indomitus

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Hello...
this is my AB-PB 4 mobo; I do not remember if it works. I'll check tonight's.

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Reply 17 of 54, by alexanrs

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Nice-looking board! I wonder why didn't more S7 boards adopt this kind of layout. There is nothing more aggravating when building an S7 machine than having all the necessary slots, but be unable to plug your boards because the processor is in the way. Or the VRM transistors.

Reply 18 of 54, by stuvize

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alexanrs wrote:

Nice-looking board! I wonder why didn't more S7 boards adopt this kind of layout. There is nothing more aggravating when building an S7 machine than having all the necessary slots, but be unable to plug your boards because the processor is in the way. Or the VRM transistors.

Because many cases have the HDs mounted were the CPU and Ram is on this board which makes it difficult to get to and if you case isn't very wide the RAM and or CPU wont even clear the HD or HD mounting tray

Reply 19 of 54, by Robin4

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indomitus wrote:

Hello...
this is my AB-PB 4 mobo; I do not remember if it works. I'll check tonight's.

Can you tell me the value of the big capacitor behind the 3 leg VRM.
What type is that VRM?

~ At least it can do black and white~