PC Chips M520

Sunday, July 14, 2013

Last Updated: Friday, August 2, 2013

Board type: Baby AT
Features: Power saving feature; 5v/12v EPROM/EEPROM setting; Internal RTC battery, and not the 486 types, either.
Physical dimensions: L: 260mm (10.2in)
W: 220mm (8.7in)
AT or ATX Support: AT power supply support.
CPU Type:
CPU Support:
CPU Notes:
Socket 7
CPUs with clock speed up to 75MHz (usually broken; so 66MHz recommended). Multiplier range is 1.5x to 3x (though, 3x is broken, so use 2.5x). Total speed 200MHz max for Intel, P166+ max for Cyrix, and PR166 for AMD K5.
Pentium P54C CPU (the one without MMX) and Cyrix 6x86 do not need VRM. For Intel Pentium P55C CPU (the one with MMX) and Cyrix 6x86L and 6x86MX use, an external VRM that handles 2.8V - 3.3V of power is required. Can use either P54C or P55C VRM, but P55C is recommended. They are rare, however.
Chipset: Intel 430VX (i430VX)
Has onboard cache:
Takes external cache:
Yes, fake cache.
Yes, uses 1x Intel COAST compliant stick cache. Supports up to 512KB. The 256KB modules are common, but the 512KB modules are rare.
Integrated Video: No
Integrated Sound: No
Controller ports: 2x IDE [PIO 0-4]
1x Floppy
PCI and ISA Slots: 3x PCI, 4x ISA
Memory Slots:
Maximum Memory:
128MB RAM with SIMM; 64MB RAM with DIMM due to i430VX chipset limitation. Some 128MB DIMM chips may work, but they have to be PC-66, and even so, it is not guaranteed. See manual in Downloads section for details.
Keyboard Support: AT DIN-5 connector. Easily can use PS/2 DIN-6 conversion adapter.
Has Mouse Support: Yes, both Serial and PS/2.
Has USB Support: No. Has USB header, but is useless due to pre-1.0 standards.
Has IrDA Support: No
Connectors: Parallel, Serial (2x), PS/2 Mouse
BIOS Notes: Illegal Award BIOSes have existed on boards with a BIOS "date" of 5/27/96, 6/21/96, and 8/26/1996. (The dates were really supposed to be 6/01/96, 7/02/96, and 8/31/96, but shows the day of each as 5/27, 6/21, and 8/26 instead.) Board maker code purports to be Tyan on illegal BIOS. No CD boot support, as such, first time it was supported was a 5/30/97 BIOS. BIOS release 19961020 (10/20/1996) is when it was known they got a legal Award BIOS license. Possible to upgrade to last known official BIOS (10/16/97). Unofficial 10/16/97 BIOS adds hard drive support up to 64GB. Also possible to use Unicore BIOS (12/07/1998).


M520 Reference
Other than BIOS notes and this above link... None yet. PC which uses it is out of commission. It works, but other projects pushed the date back.

Board Variations:

Referenced here:

i430VX-2A59Ht5BC-00 boards:-

3 PCI, 4 ISA, 4 Simm, 1 Dimm, 1 USB = PcChips M520 or Skywell SW5100.
3 PCI, 4 ISA, 4 Simm, 1 Dimm, No USB = Amptron PM7900 or Skywell M520.
4 PCI, 3 ISA, 4 Simm, 1 Dimm, No USB = Amptron PM8800.
4 PCI, 3 ISA, 4 Simm, 2 Dimm (or 4 Simm, No Dimm), optional USB = Pine PT-7502 (3 versions).
3 PCI, 4 ISA, 4 Simm, 1 Dimm, 2 USB = Houston Tech M520.


None. It's a cheaply built run-of-the-mill motherboard from the mid-1990s.

Note: A101 can use these BIOSes by default, it seems. If unsure, a second board that supports 1M, or 128KB, EEPROM can be used when flashing using Uniflash. The other board has to be on, however.
Directory - Holds every BIOS file existing from the very beginning to the very end. However, do NOT touch the extras directory!
[Note: 6/01/96 (19960601x), 7/02/96 (19960702x), and 8/31/1996 (19960831x) are illegal "Tyan" BIOSes!]
[Note to self: Organize this list like the M571!]

Directory - Diagrams and photos of the M520 and M525. Has jumper settings as well.

Directory - Holds both the original odd manual scan and the Amptron manual.
[Note to self: Scan the original manual... properly... and upload it to this site for an updated copy!]

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