Continuing construction of the old erm new computer..Posted: September 28, 2011
A great deal has happened since my previous post regarding the mini ITX computer. While I am not always able to post upto date photo’s of the project as it is happening, I am making every effort to keep posts relatively fresh from the press 🙂
Since the last blog the little machines has come along in leaps and bounds, the front panel is complete along with LED’s and switches. One issue has been how the tiny PCB that drives the LED’s will be powered. Originally I had it in my head that there was a 3 volt feed available from the ATX power supply. Sadly I discovered i was mistaken, i actually had 12v or 5v to choose from. Not promising when working with a fragile circuit that was originally intended to run from 2xAA batteries. So began a search to reduce the DC coming from the PSU, this eventually led me to regulators, specifically variable regulators, which are capable of reducing a 5v feed to as little as 1.5volts. At first i attempted to construct my own 2.8v rated regulator, using an LM317 and two resistors. As i have never done anything like the before, i found my soldering, indeed my knowledge of circuits coming under pressure. However after consulting several people on the subject, i pressed on and succeeding in a prototype circuit. As is typical for my luck, it did not work. Why, has yet to be determined, but the most likely answer is the regulator was damaged while i was struggling with a faulty soldering iron.
I have subsequently purchased another set of parts to attempt another build. If there is one small mercy out of all of this toil. It is that my work was checked by Thrashbarg from the Vintage computer forum and given the ok. Hey my soldering isn’t as bad as i thought! just a pity the damn thing doesn’t work!
While i shall work on getting it operational, I have already formulated a backup plan, involving a power supply kit which can be purchased from Maplins. The k18231a requires assembling, however the quality of the kit is far better then the one i am building. With an integrated potentiometer to adjust the output to your requirements, over all i feel this PCB is better suited to the task of powering the front panel LED’s.
Assuming i get the front panel operational, the next step will be to get the machine working.. I originally intended a CF card to be used for storage, however from first hand experience, i discovered they do not always lend themselves towards booting with an active partition on board. Whether this is something that can be fixed i had no idea. If not, i shall had to investigate the possibility of an internal 2.5″ hard drive.
Circuits aside, I was truly pleased with how the front panel graphics came out. No before you ask, i have not had the white lettering etch on. In fact what you see, is a sheet of gloss card with a front panel template printed on and placed over the original black plastic fascia. This was to me the only way to get the front done without going to ridiculous expense. After spraying the panel with matt varnish, the graphics lost their overly gloss look, which was much to my relief 🙂