A dodgy EPROM eraser


So. I was playing around with replacing some C64 ROMs. Got some used EPROMs off eBay but needed to erase them, and rather than trying unstable approaches such as sun bathing the ICs for uncertain amounts of time, I found myself in the market for an EPROM eraser…

The Order

Having been bitten before, purchasing a mains powered device from China that turned out to have non-existant electrical safety, I specifically didn’t want to get some unit off eBay or Alibaba. So I turned to Amazon.co.uk, with the - naïve, as we shall see - notion, that if I bought a product off a European outlet of Amazon, the products sold would be in compliance with European regulations.

I searched around for a bit and then latched onto this product, probably triggerd by the ostensibly French brand name KALEA-INFORMATIQUE, sold for the UK market in GBP. At 50 quid, it did not signal unreasonably low quality either, I thought.


(In hindsight, the tacky High Quality Components emblem should probably have raised my suspicion.)

The Arrival

The product arrived. The first visual inspection left a disctinct impression of a homebrew product. The build did not exactly radiate quality (some dirt and signs of handling on the case), but for what it’s worth, the plastic case and drawer seem reasonably sturdy

No standards compliance or other labels on the unit, whatsoever. Hm.


Here’s the drawer, into which the EPROMs to be erased are to be placed. All this plastic doesn’t exactly look ESD safe, but hey - plenty of space, at least…


Time for an electrical inspection, and starting with the power cord it was already pretty clear in which direction we were going to be heading. (Hint: down) The main power looks to be of the US 110 volts type, and it was just stuffed into a crooked and loosely fitting adaptor that would make it fit into most mainland Europe 230 volts power sockets (though not the UK, which also suggested this was not actually adapted for the UK market).


While some devices do work without modification with wither 110 or 230 volts, with no indication of expected voltage on the unit, I was definitely not going to plug it in without further inspection.


After removing the 8 small screws at the bottom, the truth is ready to be revealed.



So, yeah… Seriously?

Timer, tube and ballast. Well, let’s run through that left to right.


The power cord is fed through an over sized hole (debris can enter here). A knot on the cord makes for a crude strain relief, which is better than no strain relief. The cable is so loose that it can move into the unit and catch and pull on the the red wires running off to the timer. At least there’s a (loose) grommit in the hole so the cable insulation is not scuffed on the sharp edges of the hole.

The timer is clearly of Chinese origin, mechanical and rated for 220V at 1.6A. Slightly under the European net voltage of 230V but probably no worries there.

But if you get the feeling something else is worrying, you’re right. There’s no fuse in the unit. None.

Next, here’s the UV tube itself. The mount seems rather improvised and instead of a proper socket, wires are soldered directly onto the tube pins.


Shifting attention to the PCB.

Er, what’s that down there?


Yes, just a piece of metal (looks like a component leg clipping) rattling around on a mains powered board (the tube starter voltage may even be in the 1000V range) with no fuse.


And, yeah… The PCB is mounted directly - and I mean DIRECTLY - over the UV tube with no shielding whatsoever from the UV radiation. (Apart from shielding the electronics, it’d also be nice if the upwards directed radiation was reflected down by some surface, onto the EPROMs in the tray instead.)


The same goes for the wiring. That exposure is surely is going to degrade wiring insulation and component exteriors over time, possibly exposing mains potential.


Dismounting the PCB to have a look at its back side:


Yuck. Looks like this ballast board has been found on a dumpster. Actually, it probably has. It probably is a repurposed fluorescent tube light ballast from a discarded fixture. Which is not in itself bad, but besides being grimy, the board shows signs of exposure to the elements.




No way around that. This device is completely unsafe and should not be used in its current form.

I hope to rework the parts into a functioning unit at some point. At least the casing, the timer and probably the UV tube should be OK (although proper tube mounts instead of having to solder directly onto the tube would be preferable). The ballast would need to be cleaned up (or replaced completely) and shielded from UV exposure. There should be a reflective surface behind the top of the UV tube as well, to direct the radiation down towards the EPROMs. A fuse needs to be installed, of course, as well as a proper power cord with proper strain relief.

Takeaway: Amazon nowadays is no more a Proper store than Alibaba. It’s a store front for Chinese junk products, and just because you find a European sounding product in a European Amazon outlet, paying in a European currency, you will not get products up to European electrical (and fire prevention) standards.

The product is still being sold in the Amazon.co.uk store, and is all over eBay as well. I highly recommend you steer clear of it.