Digipos Pro

Digipos Pro

This is a point-of-sale system which I bought as non-working in December 2022. It was listed as powering on, but displayed no output and output a number of beep error codes. The problem turned out to be relatively easy to fix - the included single 16MB SIMM module was either faulty or incompatible and after replacing it with two 32MB EDO SIMM's from my spares it powered on correctly.

Case Pictures

Internals

Motherboard

Original Specification

Processor: IDT Winchip C6 200MHz
Motherboard: DTV-07 Ali Aladdin M1521, Socket 7, 512KB Pipeline Burst cache, 2x 72pin EDO SIMM sockets, 3x ISA + 2x PCI (3 total max.)
Video: Onboard Cirrus Logic GD-7548 (PCI)
Storage: 3.5“ Floppy + 4.3GB Seagate IDE

Current Specification

Processor: ~~IDT Winchip C6 200MHz~~ Intel Pentium MMX 200MHz
Motherboard: DTV-07 Ali Aladdin M1521, Socket 7, 512KB Pipeline Burst cache, 2x 72pin EDO SIMM sockets, 3x ISA + 2x PCI (3 total max.)
Video: S3 Virge/DX 4MB (PCI)
Network: Realtek RTL8139 10/100 + XT-IDE ROM
Audio: Labtec ESS Audiodrive 1868F
Storage: 3.5” bay mounted Compact Flash reader

Memory

As I said in the introduction, this was supplied with a single faulty 16MB SIMM and was fine after replacing it with two 32MB EDO modules.

Keyboard

After powering on the system for the first time I had ongoing issues with the keyboard not working, my KVM not detecting a keyboard, and, when the keyboard did work, the key repeat feature would not work. I also had trouble getting several types of PS/2 keyboard recognised (a basic Dell keyboard wouldn't even power up). Looking at the +5v line of the AT keyboard connector it was fine, and I tried multiple BIOS images without any improvement.

Eventually I started poking about near the AT connector on the motherboard and notice what appeared to be the typical PS/2 keyboard fuse:

Testing that for continuity I got really bizarre resistance readings, so I decided to bypass it - at that point the keyboard started to work properly. I'm not sure what failure mode the fuse was in, but it certainly hadn't 'failed open', which is what I would have expected. Anyway, bypassing it with a wire link proved that it was at fault, and my Dell keyboard came to life:

Noisy Fans

The system uses a 40x40x10mm fan over the custom PSU as well as a 50x50x10mm fan over the heatsink/heatpipe, both of which were noisy. They were removed and replaced with much bigger, slower spinning items.

Removal of Custom PSU

No standard AT/ATX PSU in this thing - it was entirely bespoke, with a bespoke motherboard header. I decided to remove the 25+ year old PSU and replace it with a modern, solid state, cool-running PicoPSU instead:

[Update] After fitting the Pentium MMX processor the PicoPSU wasn't up to the task, leading to random reboots when changing video mode, running benchmarks etc. Removal of the PicoPSU and plugging a standard ATX PSU into the breakout header stopped all of the reboots, so clearly the power draw of the Pentium 200 is at the limit (and just beyond) of what the PicoPSU can deliver. I'll need to replace it with a bigger unit - the original custom supply with it's horrible 40mm fan is not going back!

Motherboard Manual

dtv_07v4.pdf

BIOS Images

		Configuration 1	Configuration 2	Configuration 3	Configuration 4
		C6 200MHz	C6 200MHz	C6 200MHz	C6 200MHz
		2x32MB EDO	2x32MB EDO	2x32MB EDO	2x32MB EDO
		PCI CL-GD7548	PCI Millenium II	PCI Voodoo 3000	PCI Virge/DX
Test	Metric
Norton	CPU Score	429.9	429.9	429.9	429.9
Comptest	CPU Cache throughput	249554 KB/sec	249554 KB/sec	249554 KB/sec	249554 KB/sec
Comptest	RAM throughput	90991 KB/sec	90991 KB/sec	90991 KB/sec	90991 KB/sec
Comptest	Extended RAM throughput	32731 KB/sec	32731 KB/sec	32731 KB/sec	32731 KB/sec
Comptest	Dhrystones	138675	138675	138675	138675
Comptest	KWhetstones	53233	53233	53233	53233
Comptest	MegaFLOPS	7.789	7.789	7.789	7.789
Comptest	Disk throughput	1894 KB/sec	1894 KB/sec	1894 KB/sec	1894 KB/sec
Landmark	CPU of emulated PC/AT	928 MHz	928 MHz	928 MHz	928 MHz
Landmark	FPU of emulated PC/AT	1319 MHz	1319 MHz	1319 MHz	1319 MHz
Landmark	Video	8548	OFF SCALE	OFF SCALE	OFF SCALE
Speedsys	CPU Performance	130.27	130.27	130.27	130.27
Speedsys	L1 Cache	263 MB/sec	263 MB/sec	263 MB/sec	263 MB/sec
Speedsys	L2 Cache	142 MB/sec	142 MB/sec	142 MB/sec	142 MB/sec
Speedsys	RAM Throughput	108 MB/sec	108 MB/sec	108 MB/sec	108 MB/sec
Speedsys	RAM Bandwidth	224 MB/sec	224 MB/sec	224 MB/sec	224 MB/sec
Wolfenstein 3D	FPS	94.9 FPS	133.2 FPS	134.3 FPS	133.9 FPS
DOOM	Low Detail	202.41 FPS	233.41 FPS	234.87 FPS	230.52 FPS
DOOM	High Detail	44.33 FPS	55.45 FPS	55.70 FPS	54.72 FPS
Quake	320×240	26.2 FPS	28.7 FPS	28.7 FPS	28.3 FPS
Quake	Medium	11.6 FPS	13.5 FPS	13.7 FPS	12.7 FPS
Quake	640×480	N/A	10.7 FPS	10.7 FPS	N/A
3D Bench	1.0c	100.3 FPS	157.2 FPS	158.7 FPS	156.8 FPS
PC Player	Low Res	33.9 FPS	38.4 FPS	38.4 FPS	37.5 FPS
PC Player	High Res	12.5 FPS	16.2 FPS	16.2 FPS	16 FPS