VOGONS


First post, by retro games 100

User metadata
Rank l33t
Rank
l33t

Introduction
I am testing a socket 3 486 VLB Freetech 486F38 mobo - at least I think it's a Freetech 486F38 mobo. It uses the SiS 85C471 chipset. That's the same chipset used in the "high end" Asus VL/I-486SV2GX4 VLB motherboard.

The mobo
mobox.jpg

The mobo, in action
mobo.JPG

1) Link to the jumper settings on the elhvb website. Please see note 1 below.
2) Link to the jumper settings on the Stason website.

Notes
1) In order to identify this mobo, I typed in the assembly number information found between two of the ISA slots. It says: ASY 01-00385A- . I googled for that id information, and found this webpage, on the motherboards.org website. The people there seem to think that a mobo with this assembly number written on it (and also the mobo's BIOS information that the original poster provided) is a "Flexus / Freetech" 486F38 motherboard. Some websites on the net call this company "Free computer technology".

The jumper settings links above are for the 486F38X model. That's the closest that I can find. I don't know for sure what model my mobo is, if it is a 486F38X model. Every jumper setting on these webpages from links 1 and 2 above correspond with my mobo, except for one jumper. It's jumper JP7. My JP7 jumper has 1 more pin than the settings found on the internet, and the pins go from pin number 1, right up to pin number 11. On the jumper settings links above, there are no CPU type configurations that incorporate the use of pin number 11, and there is no pin number 11 drawn on to these website diagrams either.

Now, I appreciate that it's possible there are no CPU type configurations using jumper number 11. It could be reserved for future CPUs, but the thing is, when the board was shipped to me, a jumper was covering pins 10 and 11, and I have no strong reason to think it was a mistake. Unfortunately, there was no CPU installed on the board when I got it. Another thing I thought of: maybe the extra pin number 11 (when you use it with pin 10 + pin 11) controls CPUs with a write-back cache ability?

2) See note 1 above.

BIOS POST
The mobo identifies itself as a 486 VESA GREEN BIOS. Version E, no less.
bios2.jpg

Chipset information
40-PF00-001470-01101111-072594-SIS471G-U
bios1.jpg

Mysterious jumper JP7
I only count 10 pins for jumper JP7, found on diagrams on the internet.
JP7.jpg

But my mobo seems to have 11 pins for JP7
j1.jpg

Benchmarks
I removed my initial test CPU, which was a DX2-66, and replaced it with a DX-50. I set the mobo's bus speed jumper setting to 50 MHz. Everything works! Both of my cards are VLB-based: the LightSpeed VGA, and the IO controller.
wt97.jpg

Bios settings
These settings work, with a DX-50 CPU, and the bus speed set to 50 MHz.
bios4.jpg

Reply 1 of 8, by Tetrium

User metadata
Rank l33t++
Rank
l33t++

Weird, looking at that offset 1st memory slot 😜

Whats missing in your collections?
My retro rigs (old topic)
Interesting Vogons threads (links to Vogonswiki)
Report spammers here!

Reply 3 of 8, by Tetrium

User metadata
Rank l33t++
Rank
l33t++
Chewhacca wrote:

Would've been right over a mounting screw hole. I've got a mobo that covers it up completely.

Good observation there Chewhacca 😉

Kinda remembers me of the ASUS P5A-B, which had a mounting hole right in the middle of the CPU socket!! 😜

Whats missing in your collections?
My retro rigs (old topic)
Interesting Vogons threads (links to Vogonswiki)
Report spammers here!

Reply 4 of 8, by Robin4

User metadata
Rank l33t
Rank
l33t

Can i get a copy of your system bios??

I think i have the same board here.. Only with Award bios(have a 2K bug in it) and with a Via keyboard controller

I hope i could get a bios upgrade for it to solve the Y2K bug.

~ At least it can do black and white~

Reply 6 of 8, by arteq

User metadata
Rank Member
Rank
Member
Robin4 wrote:

I have got Rev G of that motherboard bios.. any help needed?

i have also this mobo, can you share your bios rev G 😀 thx

Some items for sale 😀
https://docs.google.com/spreadsheets/d/1YNG8R … dit?usp=sharing

Reply 7 of 8, by arteq

User metadata
Rank Member
Rank
Member
arteq wrote:
Robin4 wrote:

I have got Rev G of that motherboard bios.. any help needed?

i have also this mobo, can you share your bios rev G 😀 thx

btw Can Rev G detect more than two HDDs ?

Some items for sale 😀
https://docs.google.com/spreadsheets/d/1YNG8R … dit?usp=sharing

Reply 8 of 8, by pico1180

User metadata
Rank Member
Rank
Member

It is with great pleasure that I necro this decade old thread.

After days of frustration, hardware swapping, and reading to try and eliminate the ghost from this machine, I narrowed my instability problems down to the motherboard . Specifically, not working correctly with DX4 120, or a P75. But a 100 and a DX2-66 worked just fine.

Turns out that mysteries pin 11 mentioned in this post needs to be closed with 10 in order to be stable with a 120 or P75.

What is the difference between the 120 and the P75 that isn't present in any other 486 CPU, I don't now? But whatever it is, if you are using a 120 or a P75 with this board, you need 10 and 11 bridged in order for the board to be stable.

I did narrow it down to cache. the 120 and P75 would not perform reliably if 10-11 weren't bridged and the L1 cache was on. I could turn the L1 cache off, and the 120 and P75 would work fine. But if I wanted L1 cache on and use a 120 or a P75, I needed to close 10-11.

This isn't mentioned anywhere in the documentation (as already noted)

With the help of this thread I was able to sort this out and save this motherboard from the "kinda works, but not really" pile.