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UVP DE-4 EPROM Erasing System, still works after all these years!


Experienced Member
Apr 24, 2015
Recently, as part of working on a couple projects, I dug deep into my cluttered storage-spaces and dug out my old UVEPROM eraser and did a tear-down/clean-up.
It ended up being buried deep in my shed when I finally found it. It needed cleaning because it had previously stored in a location that had gotten damp.
Heavily yellowed with heat/age, mild melted spots right next to the UV bulb, and musty-smelling from mildew exposure, but otherwise intact!
For the most part, just a bunch of scrubbing the plastics, sterilizing everything with cleaning wipes, and cleaning out dust/dirt/mildew.
However, one wrinkle did come up after I removed the bulb, one of the bases had come unglued! Then, while I was inspecting that, one of the wires came loose!
Then I had to release the remaining wire (heated the pin with a lighter) and re-glue/re-solder the base back onto the tube.
Had to scrape the filament-wires to get the solder to stick to them, then I poked a hole in an old tube of super-glue and used that to re-seat the base.
A little soldering and it was good as new! Already ran a couple chips through it, 15 minutes should be enough and it didn't get overly warm during that time.
Here's the yellowed old thing, all reassembled- uvp de-4 1.pnguvp de-4 2.png
A little rusty, but not bad. Here's what a new one looks like- H_321980__50070.gif
And, lastly, I included the original manual that I found.
A pretty simple unit, just bulb, ballast, and on/off switch. No timers or anything beyond the bare necessities.
Pairs nicely with my EP1132 programmer.


  • UVP EPROM ERASE DE-4 Instructions 81007101.pdf
    79.2 KB · Views: 1
The switch on this unit is interesting, two buttons in a single switch-body.
The operation of it is exactly the same as my bedside lamp, one button is held down to start the light and released after a moment, while the other interrupts power to the tube and de-energizes the circuit. Almost like a manually-operated relay, maybe?
The one in my lamp is even older I think, Bakelite buttons built into the metal base itself, no separate switch-body.
Oh, I've seen those! Taken some apart too. With the bimetallic contacts in a glass tube and a polyester capacitor.
(a quick search to confirm we were referring to the same thing brought up this interesting repair article: https://www.ifixit.com/Guide/Repairing+Fluorescent+Tube+Starter+(fused+bimetal+strip)/29684 )
For all I know, the black-box 'ballast' unit in mine could contain something similar.
My bedside lamp seems to use a multi-tap transformer and the two buttons, one giving a higher starting voltage when pressed and maintaining a working voltage when not pressed, while the other interrupts the working voltage to shut it off.
With my lamp, if I have a sufficient static charge I can start the lamp just by touching it! (even unintentionally)
I have a magnifying work lamp that uses as circline flourescent lamp. It originally used the "hold it down until the heaters glow, then release it" pushbutton. I grew annoyed enough with the false starts, that I replaced one set of contacts with the aforementioned starter. The ballast is located on the cord. I bought my lamp new sometime in the 1960s. Still works.
Nice upgrade! Mine only has issues with starting in the winter, since I like keeping my room cold. That's some quality longevity!
I recently needed to erase some eproms so dug out my 80's vintage DIY model.
It is an E27 6W UV-C tubular bulb with cord and a socket, which was the hardest part to find back then.
Just plug it in, place it over the eprom, and leave it for 15 mins.
In this case, "leave it" means leave the room ;) as I never did get around to building a box for it.
It has lived under a shoebox in the past.
Whatever works, right? XD Somewhere I have a lone UV tube in a plastic case that originally held a sub-VHS sized tape-backup cassette.
If I knew where that was, I could build another EPROM eraser! (provided it's the right wavelength, of course. Might've been germicidal?)
At the outset of the pandemic, I took a couple of 30W UVC lamps and built a nice box for them, complete with door interlock and reflector. The idea was to toss clothes, gloves, masks, whatever close the door and let 'er rip. Didn't get as much use as I anticipated. It would probably make a dandy EPROM eraser, if only I had a few hundred EPROMs to do...

It's a nice looking box, however, constructed of workshop scraps:
That first lamp was originally design for UV light for things like rocks. It also came with a removable filter the use the less high energy UV light. Of course, the UV light through the filter would likely do little for erasing EPRMs.
I'm not at all surprised that it still works. The lamps will last almost indefinitely, as long as they are not turned on. They do age quickly if left on for long periods of time.