| Author |
Message |
spudnuty
Guest
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 Posted:
Sat Nov 12, 2005 1:35 am Post subject:
Re: Eprom Eraser, how to build |
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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
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Chris Jones
Guest
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| Posted:
Sun Nov 13, 2005 5:35 pm Post subject:
Re: Eprom Eraser, how to build |
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Asimov wrote:
| Quote: | "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: mzenier@eskimo.com (Mark Zenier)
MZ> Xref: core-easynews sci.electronics.repair:348213
MZ> In article <1131574148.397613.278000@g47g2000cwa.googlegroups.com>,
MZ> Andy <andysharpe@juno.com> wrote:
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...
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!
|
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 |
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Asimov
Guest
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| Posted:
Mon Nov 14, 2005 9:35 am Post subject:
Re: Eprom Eraser, how to build |
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"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 <lugnut808@nospam.yahoo.com>
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
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Ian French
Guest
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| Posted:
Mon Nov 14, 2005 4:48 pm Post subject:
Re: Eprom Eraser, how to build |
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"Chris Jones" <lugnut808@nospam.yahoo.com> wrote in message
news:11nelhpddj0q95f@corp.supernews.com...
| Quote: | Asimov wrote:
"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: mzenier@eskimo.com (Mark Zenier)
MZ> Xref: core-easynews sci.electronics.repair:348213
MZ> In article <1131574148.397613.278000@g47g2000cwa.googlegroups.com>,
MZ> Andy <andysharpe@juno.com> wrote:
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...
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!
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
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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. |
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stickyfox@gmail.com
Guest
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| Posted:
Mon Nov 14, 2005 5:35 pm Post subject:
Re: Eprom Eraser, how to build |
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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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Andy
Guest
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| Posted:
Sun Nov 20, 2005 1:35 am Post subject:
Re: Eprom Eraser, how to build |
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gAnd 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). --Mark
Andy replies:
Absolutely. If you put the EPROM in a large bonfire, it will also
be erased and the wavelength is much longer...... Additionally
applying a 25000 volt DC between the pins will probably erase
it . ANYTIME you overload the hell out of something's linear
parameters
with excess energy, the victim usually loses any memory...
However, the best way is to use the device physics to apply the
proper frequency to accomplish the task without risking damage
to associated internal components. In other words, do it like the
manufacturer says.
Otherwise, I found your post very informative. Thanks. I sure
hope your post wasn't some of that WRONG stuff you were talking about
on
the internet .. :>)))))
Andy |
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zapht
Guest
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| Posted:
Mon Dec 05, 2005 1:35 am Post subject:
Re: RCA TV model F35673MB, CH. CTC187CL3 BW dead set |
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i also have an RCA TV model f35673MB, Chassis CTC187CL3 that i
dead
it makes a loud squealing noise also. hoping i could get a littl
advice on servicing the set back to healt |
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kip
Guest
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| Posted:
Mon Dec 05, 2005 5:35 pm Post subject:
Re: RCA TV model F35673MB, CH. CTC187CL3 BW dead set |
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Change the HOT and the IHVT..
very common..
kip
"zapht" <zapht_renotae@hotmail-dot-com.no-spam.invalid> wrote in message
news:a9adnS4ZG8chHg7eRVnyvQ@giganews.com...
| Quote: | i also have an RCA TV model f35673MB, Chassis CTC187CL3 that is
dead.
it makes a loud squealing noise also. hoping i could get a little
advice on servicing the set back to health
|
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Jason D.
Guest
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| Posted:
Thu Dec 08, 2005 1:35 am Post subject:
Re: RCA TV model F35673MB, CH. CTC187CL3 BW dead set |
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On Mon, 5 Dec 2005 09:55:13 -0500, "kip" <nospam@nospam.com> wrote:
| Quote: | Change the HOT and the IHVT..
very common..
kip
"zapht" <zapht_renotae@hotmail-dot-com.no-spam.invalid> wrote in message
news:a9adnS4ZG8chHg7eRVnyvQ@giganews.com...
i also have an RCA TV model f35673MB, Chassis CTC187CL3 that is
dead.
it makes a loud squealing noise also. hoping i could get a little
advice on servicing the set back to health
I'm looking at exact same fault and same model as yours for a |
estimate.
RCA tend to have a run of flybacks to fail on 32" to 36" because these
flybacks are bit underspec'ed.
Cheers, Wizard |
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