VOGONS


First post, by feipoa

User metadata
Rank l33t++
Rank
l33t++

The Chaintech 486SPM, like the MSI MS-4144, has solder pads in place for native PS/2 mouse implementation. If you want to add PS/2 support to the Chaintech 486SPM, I've added some easy to follow images of which components need to be added on. I tested the mouse and it is working fine.

You can also add a coin cell CR2032 battery holdfer if you pull up D1, which would otherwise charge the battery.

If you want to add variable voltage support, replace the 909 ohm resistor with a 1 Kohm trimmer as shown. This will give you a variable 3.0 - 4.1 V to the CPU.

What's needed (for the PS/2 mouse addition):
2x 3-pin headers w/jumpers
3x 2-pin headers w/jumpers
1x 4-pin header w/PS2 mouse connector
2x inductors ~1-6 uH
2x SMD capacitors, 47 pF
2x SMD resistors, 10 Kohm
1x 7406 inverter IC
Use Modbin to add PS/2 support to your AWARD BIOS. Actually, I will just upload my modified BIOS here.

Filename
Chaintech_486SPM_PS2.zip
File size
81.45 KiB
Downloads
237 downloads
File license
Fair use/fair dealing exception

Click images for larger resolution.

Chaintech_486SPM_PS2.jpg
Filename
Chaintech_486SPM_PS2.jpg
File size
1.32 MiB
Views
5223 views
File license
Fair use/fair dealing exception
Chaintech_486SPM_PS2_Components_1.jpg
Filename
Chaintech_486SPM_PS2_Components_1.jpg
File size
323.98 KiB
Views
5223 views
File license
Fair use/fair dealing exception
Chaintech_486SPM_PS2_Components_2.jpg
Filename
Chaintech_486SPM_PS2_Components_2.jpg
File size
281.43 KiB
Views
5223 views
File license
Fair use/fair dealing exception
Chaintech_486SPM_PS2_VRM_Trimmer.jpg
Filename
Chaintech_486SPM_PS2_VRM_Trimmer.jpg
File size
298.93 KiB
Views
5223 views
File license
Fair use/fair dealing exception
Last edited by feipoa on 2018-02-05, 23:46. Edited 1 time in total.

Plan your life wisely, you'll be dead before you know it.

Reply 1 of 30, by brassicGamer

User metadata
Rank Oldbie
Rank
Oldbie

Mate this is epic, thank you. I have this board and there is very little documentation for it - just anecdotal stuff mainly. I'm looking forward to applying this mod!

Check out my blog and YouTube channel for thoughts, articles, system profiles, and tips.

Reply 3 of 30, by Marcjan

User metadata
Rank Newbie
Rank
Newbie

Hi
I have a few questions about MS-4144 rev 2.1.
Capacitors must by 47pF not 470? On mainboard i see overprint:
kondensatory.jpg

I need something beyond the inductors and this capacitors?

And please do not judge my english 😀

Reply 5 of 30, by feipoa

User metadata
Rank l33t++
Rank
l33t++

Attached is my worksheet from when I added PS/2 mouse support to the MSI MS-4144. Looks like I used 47 pF caps for the mouse and was also wondering about the 470 pF silkscreen.

Attachments

Plan your life wisely, you'll be dead before you know it.

Reply 6 of 30, by Rabanik

User metadata
Rank Newbie
Rank
Newbie

Hi. I own Chaintech 486SPM Rev. M103 with BIOS labelled 02/08/96. I made this mod with original PS/2 connectors and PS/2 mouse does not work. Keyboard works.
I "beeped" all the traces and I found out that all 4 lines of the PS/2 mouse spots are connected +5V/ground and data and clock to VT82C42N chip. See the schema. I soldered both headers, flashed the BIOS and placed the jumpers. It is my first job with soldering iron.
It looks like that the bios still does not support PS/2 mouse. Could you tell me please why the ps/2 mouse not work? Did I miss something? Is it possible that the BIOS was flashed badly?
Thank you.

Attachments

  • 3.jpg
    Filename
    3.jpg
    File size
    347.71 KiB
    Views
    4696 views
    File license
    Fair use/fair dealing exception
  • 2.jpg
    Filename
    2.jpg
    File size
    109.48 KiB
    Views
    4696 views
    File license
    Fair use/fair dealing exception
  • 1.JPG
    Filename
    1.JPG
    File size
    139.47 KiB
    Views
    4696 views
    File license
    Fair use/fair dealing exception

Reply 8 of 30, by Rabanik

User metadata
Rank Newbie
Rank
Newbie

I am not proud of my soldering job 😀

Attachments

  • DSC_1267.jpg
    Filename
    DSC_1267.jpg
    File size
    991.37 KiB
    Views
    4679 views
    File license
    Fair use/fair dealing exception
  • DSC_1265.jpg
    Filename
    DSC_1265.jpg
    File size
    924.67 KiB
    Views
    4679 views
    File license
    Fair use/fair dealing exception

Reply 9 of 30, by Rabanik

User metadata
Rank Newbie
Rank
Newbie

Here are the rest.

Attachments

  • DSC_1272.jpg
    Filename
    DSC_1272.jpg
    File size
    1.59 MiB
    Views
    4673 views
    File license
    Fair use/fair dealing exception
  • DSC_1271.jpg
    Filename
    DSC_1271.jpg
    File size
    1.54 MiB
    Views
    4673 views
    File license
    Fair use/fair dealing exception

Reply 10 of 30, by Skyscraper

User metadata
Rank l33t
Rank
l33t
Rabanik wrote:

Here are the rest.

No disrespect but those pictures look like they have been taken with a potato! 😁

In this picture the soldering looks like a mess but from the picture you posted before it's possible to see that the soldering (of the ports at least) is totally fine although perhaps a bit messy. 😀

Perhaps they are good enough after all if feipoa only wants to check if any component is missing.

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 11 of 30, by feipoa

User metadata
Rank l33t++
Rank
l33t++

Rabanik, I recommend that you follow the tutorial. You are missing all the components I highlighted in the OP, e.g. 7406 inverter, inductors, resistors, capacitors, jumper headers, etc. This board contains the solder pads for these items, but you must source the items and solder them in. Is there any reason you did not solder in the missing components?

Plan your life wisely, you'll be dead before you know it.

Reply 12 of 30, by Rabanik

User metadata
Rank Newbie
Rank
Newbie

I thought that the rest parts are required only for volt regulator. I dont have SMD capacitors 47 pF right now. It will take a few days. I let you now than. Thank you.

Reply 13 of 30, by feipoa

User metadata
Rank l33t++
Rank
l33t++

OK. I thought it was pretty explicit from the OP,

If you want to add variable voltage support, replace the 909 ohm resistor with a 1 Kohm trimmer as shown. This will give you a variable 3.0 - 4.1 V to the CPU.

Looking forward to your success.

Plan your life wisely, you'll be dead before you know it.

Reply 14 of 30, by Rabanik

User metadata
Rank Newbie
Rank
Newbie

Hi guys,
I soldered the rest of the parts and this mod works. I must only replace both big inductors for the smaller ones. But I ordered them. Thank you Feipoa!

Attachments

  • DSC_1282.jpg
    Filename
    DSC_1282.jpg
    File size
    478.83 KiB
    Views
    4548 views
    File license
    Fair use/fair dealing exception
  • DSC_1279.jpg
    Filename
    DSC_1279.jpg
    File size
    495.63 KiB
    Views
    4548 views
    File license
    Fair use/fair dealing exception
  • DSC_1278.jpg
    Filename
    DSC_1278.jpg
    File size
    475.63 KiB
    Views
    4548 views
    File license
    Fair use/fair dealing exception

Reply 15 of 30, by bjwil1991

User metadata
Rank l33t
Rank
l33t

Looks pretty good, eh!

Discord: https://discord.gg/U5dJw7x
Systems from the Compaq Portable 1 to Ryzen 9 5950X
Twitch: https://twitch.tv/retropcuser

Reply 17 of 30, by Rabanik

User metadata
Rank Newbie
Rank
Newbie
feipoa wrote:

one of the fastest with ps/2 mouse support.

Yes. I noticed too! How fast is the 486 SPM compared to MSI MS-4144? Is the 486 SPM faster than Biostar MB-8433?

Reply 18 of 30, by feipoa

User metadata
Rank l33t++
Rank
l33t++

A brief comparison of the MSI vs. Chaintech can be found here: Performance comparison of 486 motherboards with VLB-only, PCI-only, and PCI+VLB

The Chaimtech came out on top. I didnt have the Biostar in this comparison.

Plan your life wisely, you'll be dead before you know it.

Reply 19 of 30, by Rabanik

User metadata
Rank Newbie
Rank
Newbie

Hmm. Look like 486 SPM is really fast. I got some 32MB 50ns EDO single sided SIMMs and it seem that this motherboard do not support them. Is there any advantage caompared to FPM? And how fast is compared to famous Aopen AP43? Are there any tests? Is it possible to make PS/2 mod for AP43 too? Thanks.