Heating & Good VentilationPosted: May 3, 2015
A couple of years ago I wrote an article on BMV about a retro themed computer I’d built, designed to look like a Z80 Micro computer from late 70s. The build went pretty well and overall I have to say it was a success. The front panel even had blinky lights! But like many prototypes, there were one or two unanticipated bugs. Today’s article will cover the biggest of them all: heat, and how its ultimately in your own best interest not to ignore it. So pull up a chair, grab a hot beverage and lets get the party started.
At the heart of the Nomad is an MSI Fuzzy 945GM2 motherboard, fitted with an Intel Core Duo T5500 central processor and 2GB of DDR2 memory. By today’s standards the hardware isn’t very impressive, but powerful enough to run old DOS games, emulate other systems and still provide a decent working system. Windows XP Professional, while not so safe online, is still the best option for running most old software, while still being able to run Photoshop and Illustrator. Due to XP’s vulnerability on-line, I installed Xuntubu along side it, so I had a secure platform for surfing the Internet. Seriously if you have never considered Linux and you are moving away from XP, then I couldn’t recommend it enough. It’s free, open source and runs really well even on a system with limited resources. I also discovered that interfacing my TRS80 M100 via serial is much less of a headache through Linux, than it ever was using Windows.
For those of you that may have missed my earlier article, I originally used an ABS plastic enclosure to house the Nomad. At the time I thought the case would be fine, but later discovered the motherboard was cooking inside the tiny case. So much that the hot glue I had used to construct part of the case has melted and one of the SATA cables was stuck to the underside of the top lid. Using a digital thermometer I’d built, I discovered the inside of the case was reaching close to 85 degrees! Ouch!
So it was back to the drawing board, I could either find a larger case or replace the MSI board with something cooler, such as a dual core Atom board. Having past experience with Atom chips, my feelings towards them was a little jaded. As low cost CPUs go, they serve a purpose, but I’ve never found them to be that impressive in a desktop environment. I’ve seen Atom based systems advertised as compact desktop replacements, but in my experience, that is a load of old twaddle. Atom powered machines are little more than Netbooks that have been stuffed inside a compact desktop box and we all know what happened to the ill fated Netbook! Using an Atom board was simpy out of the question, for a start I was doubtful it would handling emulating a Spectrum, let alone a Commodore Amiga. I had to stick with using the Fuzzy board, so I needed to find a better case to house the guts of the Nomad. Thanks to the popularity of the Raspberry Pi, eBay is now flooded with project boxes and kits catering for hackers and builders alike. Unlike before when I struggled to find even one case, I was now faced with a torrent of cases to choose from. It still took me over a month to find a decent case that still had that ‘Altair’ look. Advertised as a Raspberry Pi enclosure, I have to say the seller was being modest.
You could probably fit 20-30 Pi inside the one case. Constructed of metal, it would be perfect for the Nomad v2. Cutting out the back and front panels proved to be a challenge, but I had faith in my trusty Dremmel. The new case was double the price of the original plastic enclosure, but for a metal case it was still relatively cheap.
Once it had arrived, I began the process of transferring the guts from the old case to the new one.
A month after the Nomad v2 was built, it randomly stopped working. At first I wondered if my fears come true, that exposure to high temperatures in the old case had damaged the components, leading to the main board giving up the ghost. Exhausting every theory, I couldn’t figure out for the life of me what was causing the machine not to work. In the end, I took the machine over to friend’s, hoping a fresh pair of eyes would see something I hadn’t. Thankfully this paid off, unlike me, my friend Peter went straight for the power supply. Not the one inside the machine, but the external brick I was using to supply 12v to the computer. I’d been so convinced heat had damaged something, I’d overlooked the simplest answer. I later realised I’d overlooked the load the Nomad was placing on the external power supply. The motherboard, CPU and drives needed at least 125watt’s and the power supply I was using fell short by a long way. Before rebuilding the Nomad, I sat down and calculated the systems power requirements and bought a PSU and ATX Pico adaptor better suited to the system. Overall the rebuild has been a success and I always get a special buzz when someone asks about the odd looking machine on the desk.