WTB: Low cost UV EPROM eraser with timer

Use a standard fluroescent lamp; for more UV, replace the bulb with a UV bulb. Get a timer at an electrical store.

Take the tube of a sun-ray lamp (from a fleemarked) and connect it via a 1N4007 diode to a 30V power supply with current limiting set to 1A. Start the tube with 250V DC in series with a 10kOhm/5W resistor. The diode will prevent the 30V-power supply from beeing zapped. The ark will burn with ca. 22V and you will smell ozone . Remove the 250V. Cool the tube with a fan to prevent the arc-voltage to jump to 80V (normal condition). EPROM erasure takes 15 minutes.

Heinz Lenk

heinzf snipped-for-privacy@web.de (Heinz Lenk) wrote in news: snipped-for-privacy@posting.google.com:

I have used a fluorescent UV germicidal bulb. Takes a while but it gets the job done. Dont forget to short out the prom pins with something conductive while erasing.

I haven't heard this before. What's the reasoning?

-- jm

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John Miles wrote in news: snipped-for-privacy@news-central.giganews.com:

To be honest, I am not sure why. I have had issues when I did not have the prom in a conductive carrier while erasing. Now that I think about it, it could be just an old wives tale. All of the prom erasings units I checked have a conductive tray.

Hi!

I've got a Stag SE15 and that doesn't have any conductive material in the tray - trust it to be awkward :-)

It's got slots where the IC legs sit in a flat metal tray.

Yours, Mark.

Rich.Andrews wrote:

That would be pretty damn necessary. Here's three datapoints from my experience.

A G15T8 Germicidal lamp in an $8 below the shelf fixture, 3 minutes. A tanning bed lamp 45 minutes. A blue filter /BLB "poster lamp", 3 1/2 DAYS. (2716/2764 vintage EPROMS).

The BLB (and BL) lamps are UV enhanced with a peak at 350 nanometers, so an ordinary fluorescent lamp would take bloody forever.

Tanning lamps peak at 300 nanometers or thereabouts, a Germicial has a strong mercury line at 258 nanometers.

Probably most convenient would be to get a G8T5, (or G6T5, depending) lamp that will fit in slimline fixtures or a battery powered safari light, or a G4T5 that will fit into (I think) those plug in the wall night lights. Probably $30, single quantity, at a specialty lamp supplier. Maybe cheaper at a barbers' supply or aquarium supply store. Or E-Bay.

Mark Zenier snipped-for-privacy@eskimo.com Washington State resident

Thanks for all the advice, but I really didn't want to build one. I wound up getting a very cheap one on Ebay for $10.

Cheers!

-Commander Dave

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