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per
April 25th, 2016, 01:02 PM
Recently I came by a "The PC+" turbo-XT motherboard, but unfortunately it has no BIOS.

Does this machine require a custom BIOS, or would any clone-BIOS work just fine? I have little experience with XT and turbo-XT clones, and I have no idea on how much variation there was between the different brands. The early PC architectures were somewhat fixed, but some sysems from different brands might have different techniques to toggle turbo-mode and such. Here it can be toggeled on/off with a hardware jumper at least.

SomeGuy
April 25th, 2016, 01:36 PM
That looks like a standard Taiwanese ERSO style XT clone motherboard. Usually there is nothing unique about them but everyone and their dog built systems with these and slapped their name on them.

I'd fully expect most of the ROMs here to work:
http://minuszerodegrees.net/xt_clone_bios/xt_clone_bios.htm

I'd go with a later Phoenix Technologies ROM as those were usually more software compatible.

Usually these will even work fine with a copy of the IBM ROMs.

Chuck(G)
April 25th, 2016, 02:33 PM
Has there been an IC (74S74) removed from the position right above the switch block? Or is this just an artifact of the photo? The solder pads look kind of lumpy. I note that this motherboard has both types of power connectors populated--that's pretty unusual--usually only one or the other has a connector installed.

T-R-A
April 25th, 2016, 02:46 PM
Has there been an IC (74S74) removed from the position right above the switch block? Or is this just an artifact of the photo? The solder pads look kind of lumpy.

Looks more like nothing was ever there to begin with (IMHO). Wave-solder machines will "bubble-up" unpopulated areas like this (similar to the feed-through vias on the board). If something was removed, it doesn't look to have been desoldered, more like cut out (though the photo is somewhat blurry when zooming in).

per
April 25th, 2016, 02:55 PM
Very many solder points over the entire card, even where there are ICs and other components installed, are pretty low standard. If everything else was neat, I'd say the 74LS74 was removed, but it's very hard to say from the overal build-quality.

If I can get my hands on an EPROM programmer, I'll try the two Phoenix 2.51 BIOSes. Otherwise I'll just roll with the latest edition of the IBM BIOS.

Plasma
April 25th, 2016, 05:06 PM
You may be interested in this generic Turbo XT BIOS (http://www.phatcode.net/downloads.php?id=101).

T-R-A
April 28th, 2016, 02:09 AM
Very many solder points over the entire card, even where there are ICs and other components installed, are pretty low standard. If everything else was neat, I'd say the 74LS74 was removed, but it's very hard to say from the overal build-quality.

Just a FWIW, if the entire board's solder quality is low, then likely (given it's manufacture-date being in the early 80's) that too much flux was applied, the solder-profile was a little too hot, or the quality of the solder itself was poor. Translation---if you get this board working again, it may not hurt to touch-up other areas of the board with some (leaded) solder.