ABit
AB-AN4T R2
Image by Microhouse
Image by mbertheau
Image by Toast_r
Image by Toast_r
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BIOS images:
| Manuf. |
POST String |
Note |
BIOS Ver. |
Core Ver. |
| AMI |
40-PBGJ-001247-00101111-072594-SIS471G-U |
board rev 1.1 |
???
|
072594 |
| AMI |
40-PAGF-001247-00101111-072594-SIS471G |
|
???
|
072594 |
| Award |
08/30/95-SIS-85C471E/G-2C4I9A12-02 |
|
02
|
4.50PG |
| Award |
10/13/94-SIS-85C471B/E/G-2C4I9A12-74 |
|
???
|
4.50G |
| Expansion slots: |
Known issues: |
- 3x 32-bit VLB
- 6x 16-bit ISA
|
- Leaky Ni-Cd clock battery
|
| Supported CPUs: |
Intel 80486DX
Intel 80486DX2
Intel 80486DX4
Intel 80486SX
Cyrix Cx486DX2
|
| Supported FSB speeds: |
20MHz
25MHz
33MHz
40MHz
50MHz
66MHz
75MHz
80MHz
100MHz
|
Notes:
AH4/AH4T/AN4R2 share the same bios
For the boards missing a VRM for 3.3V operation, here's the part list to re-implement the feature (thanks Madao !):
- Q4 = LT1085-ADJ or pin-compatible type with Low Dropout(LD1085V from ST, EZ1084, ...)
- TC15 = 10µF condensator
- TC12 = 150µF (recommended by LT1085's datasheet)
- JP52, bridged with wire by soldering.
- R77 = 270 Ohm, 4V CPU voltage, Jumper JP53
- R78 = 240 Ohm, 3.6V CPU voltage, Jumper JP54
- R79 = 220 Ohm, 3.45V CPU voltage, Jumper JP55
- R80 = 200 Ohm, 3.3V CPU voltage, Jumper JP56
- R81 = 127 ohm
- R41 and R42 is placed with 10 Ohm resistance (my estimated value) Location: between VLB slot and CPU socket
Image by Microhouse
Image by mbertheau
Image by Toast_r
Image by Toast_r