Wednesday, October 20, 2010
Huge Eprom Eraser
Over the past year i joined a small hackerspace that was just getting on its feet, one of the major initiatives we have going on is recycling... or what recycling really should be. In that time i have collected over a hundred eproms and i really should do something with them. I already have a chip programmer but lack the necessary eraser needed to prepare the chips for programming.
Naturally i went online to see what was out there... for 5 to 20 dollars i could get an eraser with a capacity of 2 or 3 chips. That won't do the trick if i want to batch test a few hundred of these things. The solution came when i found an old florescent blacklight in the corner, it drives f15t8 bulbs and i can easily get g15t8 bulbs which emit light in the crucial UVC spectrum.
The only real issue is the fact the UVC spectrum is very dangerous, enough to cause burns to the skin and your retina! I chose to use a cheap metal toolbox as an enclosure and sealed every seam to prevent light from escaping.
The rest was just dismantling the old light for the parts i needed and bolt them to the inside of the toolbox.
I used an old spring wound timer to control the time of exposure and added a safety switch to cut power if the door was open.
Also i added a tiny plastic window so i could see if the bulb was working, UVC light won't pass though, pretty much the only thing it will pass though is quartz. Everything works fine so far, it takes about 7 minutes to erase a 27c512 eprom. I will run more detailed tests when i have the free time.
Naturally i went online to see what was out there... for 5 to 20 dollars i could get an eraser with a capacity of 2 or 3 chips. That won't do the trick if i want to batch test a few hundred of these things. The solution came when i found an old florescent blacklight in the corner, it drives f15t8 bulbs and i can easily get g15t8 bulbs which emit light in the crucial UVC spectrum.
The only real issue is the fact the UVC spectrum is very dangerous, enough to cause burns to the skin and your retina! I chose to use a cheap metal toolbox as an enclosure and sealed every seam to prevent light from escaping.
The rest was just dismantling the old light for the parts i needed and bolt them to the inside of the toolbox.
I used an old spring wound timer to control the time of exposure and added a safety switch to cut power if the door was open.
Also i added a tiny plastic window so i could see if the bulb was working, UVC light won't pass though, pretty much the only thing it will pass though is quartz. Everything works fine so far, it takes about 7 minutes to erase a 27c512 eprom. I will run more detailed tests when i have the free time.
Go there...
http://dcroy.blogspot.com/2010/10/huge-eprom-eraser.html
Don
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