Hello Vogons!

I recently picked up a Zenith PC425/Sn II (486 SX-25) from eBay. Inside it, the motherboard had suffered a severe battery leakage. After removing the battery (it, and its holder fell off the board when I tried to release the plastic clip holding the battery in place) and flushing it with ample IPA, there was too much damage for it to be saved (the board was delaminating - without schematics and a parts list, it would have been impossible to resurrect).

As luck may have it, I was able to find a suitable replacement motherboard (same model of machine, but a slightly earlier revision of the same board) from a parts supplier on eBay.

I thoroughly cleaned the case and reassembled the machine with the new board installed.

I tested the battery on the replacement board and found it to be dead (not surprising - it has a date stamp of May 1992 on it!), so carefully removed it before attempting to power up the system.

The computer now seems to pass POST (albeit with the errors of "bad configuration information - replace battery" and something about missing storage configuration, which points me to running the Configuration Utility.

This is my first Zenith system, and I'm unfamiliar with the configuration of this BIOS.

Anyone able to shed some light on this issue? I'd love to get this machine up and running and added to my ever-growing collection of vintage systems. I'm about to order a replacement Tadiran Lithium battery.

I have no way to get XT-IDE running on this system at present (in case this is suggested) as I don't have an XT-IDE card or ISA network card, and although I have EPROMs that can be reflashed, I don't have an EPROM burner to get the universal BIOS on to it.

The specs (in case anyone's interested) are:

486 SX-25,
2x4MB FPM SIMMs,
Zenith proprietary (looks like 8-bit ISA, but I'll wager it actually isn't) network card with AUI interface,
Conner 210MB HDD,
Proprietary floppy drive (no power cable, so power is supplied over the I/O ribbon).

The original board came with what appears to be a VRAM upgrade (four SIPP chips installed), but I haven't yet transferred these across.

The diagram on the PSU indicates that the empty CPU-size socket on the board is for a 486/487. Any idea if this will allow me to replace the SX-25 with a DX-33 I have, or will it likely only work with 486SX/487SX chips?

Thank you!
Sarah

P.S. Of note, on the bottom label of the machine, it indicates that the model I have was made by Zenith for BT (British Telecom) here in the UK. Is this common, or do I have a particularly rare model of machine on my hands?