The backwards PC Case
A useful case mod for plug-a-holics...
I'm sure there must be plenty of tecchie types out there like me, who are forever
plugging things in and out of their PCs and don't want to be groping around the back all
the time. For a long time, I've been frustrated by how essentially identical most PC cases
there are, and that nobody to my knowledge has ever made a case which has all the drives,
IO connectors and PCI slots on the same side. (There may be a few industrial cases, but
these are usually very expensive.)
As I like to have things the way I want, I've had to resort to metal-bashing to produce a
case thet meets my needs.
I'm sure there must be a significant market waiting for any case maker who
produces a case like this..... any takers ? All it would take is a way of
exchanging the 5.25 drive bays with the PSU, and providing rear-panel switches and
LEDs - not exactly rocket science....
Whilst building a couple of PCs for friends & family recently, I realised that there is now almost no variety in the shapes & sizes of PC case available. Take a look through any PC case catalogue, and apart from one or two horizontal "desktop" cases and some huge server boxes, the only difference seems to be the proportion of 3.5 and 5.25" drive bays - they are almost all exactly the same size. OK, you can get all sorts of fancy decoration, transparent side panels, pretty flashing lights etc., but this doesn't change the fact that they are essentially all the same once you ignore the cosmetic trimmings.
This recent session of building PCs for other people made me decide
it was time to build myself a new PC, and I now faced the regular chore of finding a case
that I could adapt to my requirements. The similarity in sizes of current cases was very
frustrating, especially as the 'standard' size was just slightly too small to fit two
5.25" drives in the PSU bay - by "just slightly" I mean literally a couple
of millimetres too little height. It also didn't help that many manufacturer and reseller
sites don't make it clear whether dimensions include feet or not, and rarely show pictures
of the rear panel, which I needed to see how much space there would be for drives.
After about two days searching through websites, I finally found a case that was just that
little bit taller, without also being excessively deep - the H-600, made by AOPEN. A photo in a review, plus some
size estimates from the photo helped establish that it would be big enough.
They describe this as a "super Mid Tower", and is about 30mm taller than the "standard" ATX case. When the case arrived I was pleased to find that it had room to fit two 5.25" drives, and also a 3.5" floppy on top. It also had a very convenient "shelf" that the drives could be fixed to.
The CD and floppy drives are mounted on the shelf using two simple
angle-brackets made from aluminium sheet.
The floppy drive is horizontally spaced using a pair of 3.5-to-5.25" drive mounting brackets.
The 350W ATX PSU is mounted in what used to be the front drive bays.
Unfortunately, ATX power supplies are typically about 3mm wider than a 5.25" drive, and so need to be mounted vertically in the drive bays.
The PSU is mounted on a 3mm aluminium plate, which is screwed into
what will be the rear of the case, covering the drive bays.
Also included here is a combined IEC inlet and 4-way outlet for powering printer, monitors etc.. These outlets are switched using a relay (right) operated by the 12V supply.
Rear view - Apart from mains power in and out, the only other connectors on
what is now the the back are sockets for wide SCSI and DC power for an AIT tape drive
which will sit in an external case on top, as there wasn't room to fit it neatly inside.
Cutting clean lines in thin sheet metal is pretty much
impossible without punch tools, so I used a nibbler to cut a rough hole for the drives,
then hid the untidy edges with a bezel cut from a sheet of 1.5mm thick black plastic.
Two illuminated pushbutton switches combine power-on switch , power LED, Reset
switch and HDD LED functions.
You can make a neat external power connector for external devices by
cannibalising a 15 way D plug:
Split the shell by drilling out the mounting holes, and fix a disk drive power connector
into the shell using hotmelt glue to fill the gaps.
An earlier incarnation of this idea in the now-defunct mini-tower
format - CD drives were external SCSI ones so only the floppy needed to be on the
"front". The black rectangle is a filtered air inlet.
Remember ISA...?
One thing that seriously limited my choice of motherboard for this PC was that I need to use an ISA card to run my Picmaster in-circuit emulator system. After some hunting I found three Pentium 4 motherboards with ISA slots ( there was one other but it didn't have an AGP slot):
Soyo SY-P4I 845PE ISA (Price about GBP125)
I-Base MB820 (GBP190 from I-Base UK)
Having seen some comments on Usenet about poor ISA support from Soyo, I settled on the MB820, which had more PCI slots, supported 800MHz FSB, 8x AGP and had four COM ports.
Update : More ISA motherboards listed here
I also took this opportunity to upgrade from Win98 to 2000, and needed to use a neat utility called direct-io to allow the Picmaster software to access the ISA card hardware under Windows 2000 (it also works in XP).
Cingular