First post, by Silent Loon
Okay, my first own computer was no IBM XT, it was a Siemens AT, model name "PCD-2L" with a 286 12Mhz cpu, 4MB RAM and a 20MB MFM harddisk inside, and it looked - or looks like this:
This model wasn't really for the consumer market, it was targeted on small offices or companies that liked to have some kind of "slim line" PC I think.
Some month ago I wanted to revive it - but only partly succeeded: The cmos battery was - after nearly 20 years - finished. So I had to type the bios parameters of the machine every time I started it - annoying! Of course I thought about changing the battery, but I discovered that it was somehow soldered on the board, and I'm not very good in soldering. Inside the machine it looked like that:
What you see is the mainboard of the PC, it's a full size "Slot-Cpu-Board" or Single Board Computer (SBC) that uses a passive 4-Slot ISA backplane. This is an industrial standard still today, but siemens abandoned this path some time afterwards, at least for their consumer products.
I put the floppy cable off, so the battery is visible. The two other cables go from the hard disk to the mfm hd-controler, which was at that time not part of the mainboard.
Note that the board is equipped with an AMD cpu!
Well, I forgot about reviving the machine, until I stumbled over an auction where "old 386 and 486 siemens industrial cpu boards" where sold. I got them for arround 7€!
I wonder if they would fit - and if it would work after all.
It works! The boards even have new batteries - it seems as if they where stored in reserve and never used!
So I pumped up my ol' 286 to a 386DX33:
As you can see, this board has allready an IDE controller - and as the MFM hd is very loud, I took a CF-card (256MB, with IDE adapter) instead as hard disk (below the cables).
Note that the PSU (Made in Italy!) and the system fan are separated - which made it easy to change the old PAPST "vapor cleaner" against an Artic Cooling AF8025L (same air flow but almost quiet). So the system is now nearly noiseless.
I didn't stop there - here you can see the PCD with a HX board (I bought separately) and a Pentium 75 Mhz:
But is combination was allready too fast for some purposes so I finally voted for the 486DX33 board:
My old PCD-2L was deaf and dumb - there was no soundcard inside. And just a 256k VGA card... So here's what I put in:
- A Diamond Speedstar Pro ISA SVGA card with 1MB and Cirrus Logic chipset (best image quality of all ISA VGA cards that I have, faster than Tseng 4000ax)
- A Turtle Beach Tropez Classic Wavetable soundcard, that is SBpro compatible, has a true Yamaha OPL3 (YMF 262) and a Wavefront synthesizer that provides General Midi (and with a special soundfont even some kind of MT-32-) compability.
- A Gravis Ultrasound Classic Rev. 2.2 with 1MB sample RAM:
The big advantage is that you can change the system configuration and thereby the hardware speed within minutes. Here are the boards not in - but "ready to use":
From left to right:
the original 286 board; a 386-20 board with a "ad-on" Tseng 4000 graphics card that sits on the board (Does anyone know the pinouts?), a 386-25 board, the 386DX33 board and finally the Pentium 75 with passive heatsink.