$15 Ebay EPROM Eraser Teardown - Page 1
Forum section: electronics / general

author: Mikek400
author_rank: Regular Contributor
timestamp: April 13, 2016, 10:34:48 am
content: Yeah, I know. It is a steaming pile of crap but before buying it I wondered about its construction.Thought about making my own but this was too cheap to pass up.Wires are soldered directly to the UV tube.. And oddly there is a piece of metal in the tube rattling around. Not a filament. Looks almost like solder?Anyhow, it's cheap plastic junk but for the amount it will be used, it will probably work good enough.

author: Mikek400
author_rank: Regular Contributor
timestamp: April 13, 2016, 10:39:39 am
content: More pics

author: Mikek400
author_rank: Regular Contributor
timestamp: April 13, 2016, 10:49:54 am
content: I'm happy for the price. I mean it feels like junk. It is just so light. hahaIf I had built my own it wouldn't have been as nice, more than likely.

author: Gyro
author_rank: Super Contributor
timestamp: April 13, 2016, 10:50:41 am
content: Doesn't look like junk to me.When I built one, I soldered to the tube pins too - not something I'm planning on changing, even every few years.A bit of ESD foam might be a useful addition.

author: Mikek400
author_rank: Regular Contributor
timestamp: April 13, 2016, 10:55:35 am
content: Quote from: Gyro on April 13, 2016, 10:50:41 amI guess I should have written that differently. I'm not unhappy with it all. It is about how I expected.It only cost me $15 so it is great.ESD foam would be good I think too. Next time I come across some I will put it in there.

author: plazma
author_rank: Frequent Contributor
timestamp: April 13, 2016, 11:19:39 am
content: It's surprisingly good for the price. I'm happy with my unit. I use it for Commodore 64 roms.

author: z01z
author_rank: Regular Contributor
timestamp: April 13, 2016, 12:49:41 pm
content: How long do you need to run it to clear and EPROM?What about the heat generated? Won't the tube become hot?

author: CJay
author_rank: Super Contributor
timestamp: April 13, 2016, 01:00:51 pm
content: Quote from: wilfred on April 13, 2016, 10:45:02 amI've successfully made EPROM erasers using actinic UV tubes a couple of times, the actinic tubes emit the short wavelength light needed to erase EPROM cells as well as having the handy side effect of killing bacteria so your chips will be safe to lick.

author: xwarp
author_rank: Frequent Contributor
timestamp: April 13, 2016, 03:33:23 pm
content: Quote from: wilfred on April 13, 2016, 10:45:02 amWhen I converted my truck from carburetor to GM TBI, I needed the ability to erase the 2832 eeproms. I bought one of those cheap dog pee/scorpion finder handheld black lights. Ordered a few of those UV-C lamps off ebay and away I went.Yes, they work to erase eeproms and very effectively in about 10 minutes.

author: rf-loop
author_rank: Super Contributor
timestamp: April 13, 2016, 04:13:45 pm
content: Quote from: Mikek400 on April 13, 2016, 10:34:48 amInside tube you mean?No, these are not solder. They are Mercury drops (Hg). Without these it do not work.How long time need for erase.It depends.. so many things.Normally if want good result it need test. (erase, test, erase more, test, erase more...untila just all bits are erased. Then use some multiplication and use this time (for same type of UVEproms just in your machine. Very much too long time is also not very good. If all bits are turned they may turn back after some time time if erase is not perfect.I use this. Erase 5 min. Look if all 1, if all are 1 (erased) then I use total 15 minutes. If not, erase agen 5minute. If all 1 then I use total time 30min. (time all just erased x 3) (some chips may be more fast and depending lamp UV intensity etc things.)For good long time reliability well done erasing is mandatory. But also programming (voltages, timing etc) need do exactly with chip specifications. (there are less or more bad "programmers" and then real quality Programmers)

author: bingo600
author_rank: Super Contributor
timestamp: April 13, 2016, 04:28:32 pm
content: I have one , and am quite happy with it.Had to change the mains plug , and the mains copper-cores are quite "flimsy" , but it doesn't draw much current.Got it for 9€/Bingo

author: Gyro
author_rank: Super Contributor
timestamp: April 13, 2016, 04:39:15 pm
content: It's worth also having a supply of EPROM labels to stick over the window after programming. The ones I use are actually aluminised write-protect labels left over from 5 1/4" floppies. Blocking all light will maximize the programmed life of the device against long term exposure to daylight, florescent light, ....people looking for dog pee, scorpions etc.

author: SeanB
author_rank: Super Contributor
timestamp: April 13, 2016, 06:10:05 pm
content: Built one a few years ago ( a lot of years ago....) using the arc tube out of a mercury vapour lamp. Used the arc tube, the starting resistor and a 9W ballast to drive it. Was quite good at making ozone along with erasing eproms when it was close to them. Put it in a small drawer box with a microswitch to switch lamp off when you opened the drawer. Piece of black antistatic foam to hold the chip in the drawer door worked well.

author: Fungus
author_rank: Super Contributor
timestamp: April 13, 2016, 06:26:22 pm
content: You can get LEDs with peak wavelength under 280nm these days.Would they do the job? Would be fun to try...(I'm guessing a powerful one would be expensive though - there must be a reason why they don't sell LED EPROM erasers)

author: Kilrah
author_rank: Unknown
timestamp: April 13, 2016, 06:59:31 pm
content: Quote from: SeanB on April 13, 2016, 06:10:05 pmYum, brings back memories of the ozone smell during startup of some HMI projector I used back in the day. Wonder what actually causes it, excessive bulb resistance before it's heated up that causes some current to flow outside of it? Never looked into it.

author: joeqsmith
author_rank: Super Contributor
timestamp: April 13, 2016, 10:02:36 pm
content: That's a lot nicer than my old one. Mines a plastic box with a bulb and a plug. Not even an on/off switch let alone a fancy timer.

author: Mikek400
author_rank: Regular Contributor
timestamp: April 27, 2016, 04:04:02 am
content: Upgraded it with aluminum tape.The top inside was starting to get discolored from the UV.

author: helius
author_rank: Super Contributor
timestamp: April 27, 2016, 05:06:42 am
content: With the supply of used erasers from Silicon Valley at almost as low a price I don't see the point?I don't even see a tray interlock on that unit.

author: Fungus
author_rank: Super Contributor
timestamp: April 27, 2016, 07:46:11 am
content: Quote from: helius on April 27, 2016, 05:06:42 amNot everybody lives in California...?

author: wkb
author_rank: Super Contributor
timestamp: April 27, 2016, 08:25:01 am
content: In a pinch: find an old (the older the better because it produces more (unhealthy..) UV-C) suntan lamp in your local recycling store. That is what we used in the dim past for lack of €€ (well, real money, so Dutch guilders, at the time)The newer tanning lamps are better filtered and not nearly as effective for erasing EPROMs. They work fine for exposing photoresist PCB material though.Cheapest but slow: put the EPROMs in the sun. Takes a day or so in .nl

author: Mikek400
author_rank: Regular Contributor
timestamp: April 27, 2016, 09:03:43 am
content: Well they sure aren't cheap here in Japan. If you can find one expect to pay $150 or more for it.Maybe you could make a business of selling them around the world for cheap.Yes, there are no interlock switches, but its not a laser and you can't directly see the lamp no matter what angle you look because of the way the drawer opens.Although I am from the US, I don't live there.

author: timb
author_rank: Super Contributor
timestamp: April 27, 2016, 09:32:19 am
content: I'm in the US and don't see them come up on eBay very often. When they do, often times they don't have the tube/bulb (or it's bad). Shipping can also be costly, as a lot of them are the large bulk erasers designed for manufacturing facilities and such.You sometimes see old EEPROM programmers come up, which include erasure drawers, but they always seem to be listed for $500+ and sit for months with no sale. Most require DOS software and parallel ports, which is a no go. They're a bit heavy, too.I ended up buying one of these cheap units on eBay to erase some EEPROMs for upgrading firmware in old test gear. The build quality is atrocious. Seriously.The only reason the power cord doesn't pull right out of the case is because they *tied a knot* in it. At least they put a rubber grommet in the hole I guess...This is how the wires from the lamp (and the mains voltage from the power switch) are attached to the circuit board; no form of strain relief, just soldered directly to protruding leads on the bottom of the board.The timer is actually fairly well constructed and does seem to work consistently. I thought about replacing it with a 555+Pot+Relay, but, effort...My unit smelled really bad, that fragrant "gasoline mixed with plastic" aroma that only the highest quality Chinese wares posses. So I took everything out of the case and soaked it in degreasing dish soap and hot water for two hours, then let it air out for a day. Took most of the smell away, so during reassembly I added heat shrink to any exposed solder connections. I also made sure to cable tie the wires coming from the bottom of the board, so they don't flop around and break off. I also added a little handle to the drawer to make it easier to open.I also added a thin layer of anti-static foam to the bottom of the drawer; just enough to keep the ICs from moving around.It's not perfect, but for $15 it'll work fine for as often as I'll use it. It beats my old method of erasing PROMs, which was to use my humidifier! (It has a UV lamp that kills germs in the water, after it leaves the tank and before it gets to the filter wick. I'd simply run it without water and tape the PROM right under the bulb. Worked great in a pinch!)

author: RGB255_0_0
author_rank: Frequent Contributor
timestamp: April 27, 2016, 10:20:46 am
content: Using green as a current-carrying conductor should demand castration as punishment.

author: SeanB
author_rank: Super Contributor
timestamp: April 27, 2016, 11:58:52 am
content: That timer is a washing machine timer unit, commonly used on the cheap plastic twin tub washing machines. As it will run for years with the 5A inductive load of the wash motor here it will do fine. Eventually the grease will get hard and it will stick, but you can just replace it with a $2 new one, or strip it and clean and relube it.

author: knks
author_rank: Regular Contributor
timestamp: May 30, 2016, 11:45:13 pm
content: Quote from: CJay on April 13, 2016, 01:00:51 pmDid you use the ones like in this link? Those from Masters don't look right - I always thought the 253.7nm ones must be transparent

author: CJay
author_rank: Super Contributor
timestamp: May 31, 2016, 03:35:11 pm
content: Quote from: knks on May 30, 2016, 11:45:13 pmThe ones I used were intended for fish pond water sterilisers and they were clear, short wavelength ones, from a quick google I think the Philips ones you link probably wouldn't work too well, if at all.

author: Melt-O-Tronic
author_rank: Frequent Contributor
timestamp: May 31, 2016, 10:11:34 pm
content: They definitely look & feel like junk, but mine works great too.Tangent: You see in the datasheets sometimes the erasure time for different types of exposure and I remember fluorescent light being one (I don't recall the time/dose). So a couple months ago, I put a 35 year old 2716 in direct contact with a 15W desk lamp tube for 3 days . . . it cleared 1 bit.