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Eprom Eraser, how to build

F

Franc Zabkar

Is it possible to build an inexpensive UV EPROM ERASER out of those
innexpensive UV LED Flashlights or the bulb from a bug zapper such as
this one:
http://images.canadiantire.ca/media...ighting/InsectControl/0593550_450_SC_d1e3.jpg
Click to expand...


"An 'anti-bacterial' toothbrush holder (AU$25), a single capacitor and
a simple IC carrier are all you need for a fully-functioning EPROM
eraser."

http://www.siliconchip.com.au/cms/A_104058/article.html


-- Franc Zabkar

Please remove one 'i' from my address when replying by email.
 
A

Andy

Is it possible to build an inexpensive UV EPROM ERASER out of those
innexpensive UV LED Flashlights or the bulb from a bug zapper such as
this one:

Andy writes:

No. The frequency of the emission of a UV LED is far removed from
the
particular NARROW band of UV frequencies that can erase an EPROM...

I forget the actual center frequency needed for EPROM erasure, but if
the
spectral frequency is not very very close to it, the EPROM won't erase.
If you research it on the internet, you will learn a great deal...

For instance RF is RF, but an AM radio is not sensitive to TV
channels...

Same with UV, which covers a very wide spectral range. An EPROM is
like
a little , tuned, receiver.....

If I remember correctly, the germicical lamps will put out the proper
UV
frequency. They are fairly expensive, tho....... UV LEDs are
definitely
NOT near the proper frequency range......

Andy
 
A

Andy

Andy replies even more:

I just remembeedr that the EPROM frequency is 253.7 nanometers.

Here is a website that tells about how the erasers work. It should
answer your questions.

http://xtronics.com/memory/how_EPROM-works.htm


If you build yourself one, and can find a cheap source for parts,
please
post it on this newsgroup. I've been wanting to do this for some
time, myself, but am just too damn lazy to go to the trouble for
something
I'll only use once a year....... Thanks, and good luck

Andy
 
S

Sjouke Burry

Franc said:
"An 'anti-bacterial' toothbrush holder (AU$25), a single capacitor and
a simple IC carrier are all you need for a fully-functioning EPROM
eraser."

http://www.siliconchip.com.au/cms/A_104058/article.html


-- Franc Zabkar

Please remove one 'i' from my address when replying by email.
Click to expand...

Could You refrain from giving links where you can only read the
first few lines,and have to pay $$$ fro the rest???
Unless of course you want to spam for a commercial URL.

Burry.
 
J

James Sweet

J

James Sweet

Michael said:
You have to pay to read that article!?!??
Click to expand...


It's the whole magazine available online, you should be able to preview
a few articles for free every once in a while. There's a trick you can
use to view any of them free at any time too.
 
J

James Sweet

Could You refrain from giving links where you can only read the
first few lines,and have to pay $$$ fro the rest???
Unless of course you want to spam for a commercial URL.
Click to expand...


Why? He doesn't work for the magazine.

Just do a search in Google for the first line of text from the article
and access it from there, you'll be able to read the whole thing. Not
sure why you didn't get to preview it unless you're on dialup and
someone with your IP recently read it.
 
F

Franc Zabkar

Could You refrain from giving links where you can only read the
first few lines,and have to pay $$$ fro the rest???
Unless of course you want to spam for a commercial URL.

Burry.
Click to expand...

Sorry. The bulk of the article basically describes how to increase the
time constant of the circuit by adding a large capacitor in parallel
with the existing one. That's about it.

-- Franc Zabkar

Please remove one 'i' from my address when replying by email.
 
A

Andy

Could You refrain from giving links where you can only read the
first few lines,and have to pay $$$ fro the rest???
Unless of course you want to spam for a commercial URL.--- Sjouke



Andy comments:

I have just wasted more time reading your personal net police
reply than I have on following the rest of this thread. Thank you
for trying to teach me patience , tolerance, and understanding. You
didn't go a good job of it , tho.....

Andy
 
M

Mark Zenier

Is it possible to build an inexpensive UV EPROM ERASER out of those
innexpensive UV LED Flashlights or the bulb from a bug zapper such as
this one:

Andy writes:

No. The frequency of the emission of a UV LED is far removed from
the
particular NARROW band of UV frequencies that can erase an EPROM...

I forget the actual center frequency needed for EPROM erasure, but if
the
spectral frequency is not very very close to it, the EPROM won't erase.
If you research it on the internet, you will learn a great deal...
Click to expand...

And a lot of what you learn will be WRONG.

An EPROM cell will get erased by any electromagnetic radiation shorter
in wavelength than some limit determined by the device physics. (You can
even use X-Rays is you can find a source powerful enough).

But that wavelength is shorter than the 350 nanometer output of a lot of
UV lamps. Ie. the /BL or /BLB "poster lights" that are relatively safe.
These can light up the phosphorescent ink on posters, cure glue or
printed circuit etch resist, but not erase EPROMs. (Or at least not in
any reasonable length of time. Back in my starving student days I did
it with a poster lamp, but not many people want to wait for 3 1/2 days).

A 300 nanometer tanning bed lamp will do it in about an hour, a 258 (?)
nanometer germicidal lamp in just a few minutes. In other words,
if you can't get a sunburn or worse, it won't erase an EPROM.

Mark Zenier [email protected]
Googleproofaddress(account:mzenier provider:eskimo domain:com)
 
S

spudnuty

I have one that I found in a pile of electronics stuff that was tossed.
I always was gonna do some projects with it but..... It's a Prometrics
Model 117. It has a mechanical timer that controls exposure. It works
but I pulled the power cord for some other project. I'd be glad to send
this to someone who could use it if they'd pay the shipping. eMail me
for pics and arrangements: spudnuty<at>aol<dot>com.

Richard
 
A

Asimov

"Mark Zenier" bravely wrote to "All" (11 Nov 05 03:41:15)
--- on the heady topic of "Re: Eprom Eraser, how to build"

MZ> From: [email protected] (Mark Zenier)
MZ> Xref: core-easynews sci.electronics.repair:348213

MZ> In article said:
Is it possible to build an inexpensive UV EPROM ERASER out of those
innexpensive UV LED Flashlights or the bulb from a bug zapper such as
this one:

Andy writes:

No. The frequency of the emission of a UV LED is far removed from
the
particular NARROW band of UV frequencies that can erase an EPROM...

I forget the actual center frequency needed for EPROM erasure, but if
the
spectral frequency is not very very close to it, the EPROM won't erase.
If you research it on the internet, you will learn a great deal...
Click to expand...

MZ> And a lot of what you learn will be WRONG.

MZ> An EPROM cell will get erased by any electromagnetic radiation shorter
MZ> in wavelength than some limit determined by the device physics. (You
MZ> can even use X-Rays is you can find a source powerful enough).

MZ> But that wavelength is shorter than the 350 nanometer output of a lot
MZ> of UV lamps. Ie. the /BL or /BLB "poster lights" that are relatively
MZ> safe. These can light up the phosphorescent ink on posters, cure glue
MZ> or printed circuit etch resist, but not erase EPROMs. (Or at least not
MZ> in any reasonable length of time. Back in my starving student days I
MZ> did it with a poster lamp, but not many people want to wait for 3 1/2
MZ> days).
MZ> A 300 nanometer tanning bed lamp will do it in about an hour, a 258
MZ> (?) nanometer germicidal lamp in just a few minutes. In other words,
MZ> if you can't get a sunburn or worse, it won't erase an EPROM.


An alternative is the warm midday sun in the summer. Someone tried to
convince me I could leave an eprom out on the beach for years and it
wouldn't erase but that was bs as anyone who gets a sunburn can attest.
I exposed pcb's outdoors in my early experiments. It took about 12
minutes under the Sun compared to about 2 minutes with a proper lamp.

A*s*i*m*o*v

.... Puddy-tat's not so bwave in Gwanny's microwave!
 
C

Chris Jones

Asimov said:
"Mark Zenier" bravely wrote to "All" (11 Nov 05 03:41:15)
--- on the heady topic of "Re: Eprom Eraser, how to build"

MZ> From: [email protected] (Mark Zenier)
MZ> Xref: core-easynews sci.electronics.repair:348213



MZ> And a lot of what you learn will be WRONG.

MZ> An EPROM cell will get erased by any electromagnetic radiation
shorter
MZ> in wavelength than some limit determined by the device physics. (You
MZ> can even use X-Rays is you can find a source powerful enough).

MZ> But that wavelength is shorter than the 350 nanometer output of a lot
MZ> of UV lamps. Ie. the /BL or /BLB "poster lights" that are relatively
MZ> safe. These can light up the phosphorescent ink on posters, cure glue
MZ> or printed circuit etch resist, but not erase EPROMs. (Or at least
not
MZ> in any reasonable length of time. Back in my starving student days I
MZ> did it with a poster lamp, but not many people want to wait for 3 1/2
MZ> days).
MZ> A 300 nanometer tanning bed lamp will do it in about an hour, a 258
MZ> (?) nanometer germicidal lamp in just a few minutes. In other
words, MZ> if you can't get a sunburn or worse, it won't erase an EPROM.


An alternative is the warm midday sun in the summer. Someone tried to
convince me I could leave an eprom out on the beach for years and it
wouldn't erase but that was bs as anyone who gets a sunburn can attest.
I exposed pcb's outdoors in my early experiments. It took about 12
minutes under the Sun compared to about 2 minutes with a proper lamp.

A*s*i*m*o*v

... Puddy-tat's not so bwave in Gwanny's microwave!
Click to expand...

I tried eresing EPROMs in the sun, in Australia (i.e. proper sunlight).
From what I can remember, it took more than a week. That makes me very
scared of looking into one of those eraser tubes which can do it in
minutes. PCB resist uses longer, less dangerous wavelengths.
Chris
 
A

Asimov

"Chris Jones" bravely wrote to "All" (13 Nov 05 15:06:55)
--- on the heady topic of "Re: Eprom Eraser, how to build"

CJ> From: Chris Jones <[email protected]>
CJ> Xref: core-easynews sci.electronics.repair:348423

CJ> I tried eresing EPROMs in the sun, in Australia (i.e. proper
CJ> sunlight). From what I can remember, it took more than a week. That
CJ> makes me very scared of looking into one of those eraser tubes which
CJ> can do it in minutes. PCB resist uses longer, less dangerous
CJ> wavelengths. Chris


Okay, thanks for the heads up on that one. I'd like to be an eprom on
an Australian beach any day, as we're headed for winter here soon. In
the early 70's my roomy fell asleep under a tanning lamp. The skin was
as red as a cooked lobster's and then peeled off in swatches for days
after that. Not a pretty sight that lady was.

A*s*i*m*o*v

.... Anyone not wearing 2,000,000 sunblock is gonna have a REAL_ BAD_ DAY_7
 
I

Ian French

Chris Jones said:
I tried eresing EPROMs in the sun, in Australia (i.e. proper sunlight).
From what I can remember, it took more than a week. That makes me very
scared of looking into one of those eraser tubes which can do it in
minutes. PCB resist uses longer, less dangerous wavelengths.
Chris
Click to expand...

Hi all,

For a real, serious, and cheap solution to erasing EPROMS try this link
http://www.rampantapathy.co.uk/epromeraser.html

He uses a 6 inch long, 4 Watt, Germicidal lamp in conjunction with a "Maplin
Torch", which in its normal state contained a normal flourescent tube.
The lamps are available from http://www.firstlightdirect.com/, and work out
to about £8.50 each including Postage and VAT.
I have just recently used a similar set up with a 9 inch tube and it works
fine, erasing the EPROM in about 10 minutes when place 0.5 inch from the
tube.
If any of you do this BE SURE to place the tube etc inside a light proof box
BEFORE switching the power on, this Wavelength of UV ( about 250
nanometres) is DANGEROUS to your eyesight.
I have found that a cardboard Boxfile is OK.
Bye,

Ian.
 
S

[email protected]

If you just need one or two eproms erased, go to wal-mart and cram them
up in the bottled water purifier at the front door. Pick them up on
your way out. :)
 
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