VOGONS


First post, by nuno14272

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Hello, I've just bought this socket 2 motherboard.

Thas a really strange layout. socket 2 with pci !, with IDE but no FDD ? whats happening...
socket 2 suposelly doesnt support 3,3v cpus but board as a 3,3v stamped.

Can you help me identify the manufacter and possibly the manual and jumpers ?

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Last edited by nuno14272 on 2020-12-20, 18:17. Edited 1 time in total.

1| 386DX40
2| P200mmx, Voodoo 1
3| PIII-450, Voodoo 3 3000

Reply 1 of 8, by computerguy08

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A BIOS dump could help a lot with identification. Can't seem to find it in UH19 yet, based on slot count.

Looking for a motherboard? You can find it in Ultimate Retro: https://www.ultimateretro.net/motherboards/search
Join our Discord server here: https://discord.gg/HWWH7hsk2p

Reply 2 of 8, by nuno14272

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UPDATE: just try the board..came with a AMD DX4-100.. it boots..

The BIOS Numbers are:
12/07/94 2A4X5UZ4-00

Searxhing vives me almost no results, saying its a UMC modelo 1415..

Any ideas about This board?

1| 386DX40
2| P200mmx, Voodoo 1
3| PIII-450, Voodoo 3 3000

Reply 3 of 8, by mkarcher

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nuno14272 wrote on 2020-12-11, 16:21:

Hello, I've just bought this socket 2 motherboard.

Thas a really strange layout. socket 2 with pci !, with IDE but no FDD ? whats happening...
socket 2 suposelly doesnt support 3,3v cpus but board as a 3,3v stamped.

You are right: Mechanically, that is a socket 2. But from functionality, it seems to be a full-featured socket 3. As the mechanical difference is just about the outer pins near the pin-1 corner, and the only processor that uses the outer ring and is actually available is the Pentium Overdrive which fits both sockets, it doesn't matter in practice that they fitted the "wrong" socket. You can easily see that this board has socket-3 functionality by finding the voltage regulator with its heatsink near the processor socket.

IDE but no FDD also made sense at that time: The UM8886 south bridge as a local-bus connected IDE controller, so it's basically "for free" (you still need space on the board for the connectors and the traces), whereas FDD, serial and parallel can be provided at full performance using ISA multi I/O cards that already were cheap commidity items in 1992. To provide these ports onboard, you would need to place a Super I/O chip, its crystal, the serial port level converters and all required connectors on the main board without any advantage in performance. On the other hand, VL IDE controllers were expensive and difficult to setup, whereas the UM8886 is soft-configurable and initialized for the correct speed by the BIOS routines provided by UMC.

Reply 4 of 8, by dionb

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Very interesting mix of new and old here. This is a late motherboard, all the chips I can read are from first quarter of 1995. That means this thing is contemporart with Intel's i430FX and Pentium chips actually performing well and going mainstream. Put into that context the IDE onboard isn't so weird. That late date also explains the 3V support, any 486 by this time would be 3V, and 72p SIMM slots. Now a 486 in 1995 is by definition a low-end beast and this board looks to be using up a lot of old stock. It's not just the So2, it's also all the tantalum caps instead of electrolytics (back then they were cheaper) and through-hole resistors and caps instead of SMD, as well as leaving out the SuperIO so you can use a generic old ISA card.

As for ID, I'm afraid you've already done that - UMC 1415. Just no more info on it available.

Reply 5 of 8, by nuno14272

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Thanks for the explanation... This motherboard is like new.. really NOS... And theres a ton of jumpers and no markers on the board. Not even the most important...

Good enoug the board works. Fiz the Dallas mod, but not going to change.nothing because dont know what the jumpers do..

1| 386DX40
2| P200mmx, Voodoo 1
3| PIII-450, Voodoo 3 3000

Reply 6 of 8, by evasive

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1415 sounds like A-Trend but what we have listed there has a different layout:
https://www.ultimateretro.net/en/motherboards/6911

However, I have a feeling this could an A-trend board seeing the ATC-1425A:
https://www.ultimateretro.net/en/motherboards/6675
(that btw has this "2A4X5UZ4" string mentioned in the manual!).

Reply 7 of 8, by evasive

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oho. We have something very similar here:
https://www.ultimateretro.net/en/motherboards/9764

Can you please check if those settings make sense? So check what CPU you have and indeed the settings according to the table are a match?