12 Jun
2009
12 Jun
'09
5:16 p.m.
On Fri, 12 Jun 2009 13:41:40 -0700, Eric Smith wrote:
A regular camera flash is probably the wrong thing to
use, as by design
they don't emit a large amount of short-wave UV.
usually the UV filter is in the lens / cover not the cheep glass tube.
The other Bob
8:24 p.m.
On Jun 12, 2009, at 8:17 PM, Eric Smith wrote:
I'm seeing camera flash units at thrift stores (both good ones and
crappy ones) usually for less than five bucks. If it is indeed a
viable erasure method, it's damn cheap to do.
-Dave
--
Dave McGuire
Port Charlotte, FL
usually the UV
filter is in the lens / cover not the cheep glass
tube.
Yes, and presumably people don't want to break their expensive
camera flash to use to erase EPROMs. 
9:43 p.m.
On 12 Jun 2009 at 20:24, Dave McGuire wrote:
crappy ones) usually for less than five bucks. If it
is indeed a
viable erasure method, it's damn cheap to do.
Well, the story says the light disrupted the EPROMs. Consider the
distance between the flash and the unit in the story and the flash
would have to be bright beyond OSHA standards to effect erasure..
And the story refers to "rebooting" as a recovery method--impossible
if the EPROMs were truly being erased.
I suspect that what the story describes is more of a photoelectric
effect, like shining a bright light on a decapped DRAM.
On the other hand, how bright can an eraser get? If I were to
remove the innards of a 250W mercury-vapor bulb (leaving just the
quartz arc tube) and install that in an EPROM eraser (with suitable
ventilation), how long would it take to erase UV EPROMs? Would the
EPROMs survive?
--Chuck
14 Jun
14 Jun
midnight
On Jun 12, 2009, at 9:43 PM, Chuck Guzis wrote:
Ahh ok, I hadn't read the story. I think this has been discussed
before. I built a Nixie clock as a gift for my then-girlfriend,
using a quartz-windowed 8751 microcontroller. She once tried to take
a picture of it, and it promptly crashed. :)
Here are some pics; note the exposed microcontroller:
http://www.neurotica.com/wiki/Nixie_Clock_2
crappy ones)
usually for less than five bucks. If it is indeed a
viable erasure method, it's damn cheap to do.
Well, the story says the light disrupted the EPROMs. Consider the
distance between the flash and the unit in the story and the flash
would have to be bright beyond OSHA standards to effect erasure..
And the story refers to "rebooting" as a recovery method--impossible
if the EPROMs were truly being erased.
I suspect that what the story describes is more of a photoelectric
effect, like shining a bright light on a decapped DRAM. On the other hand, how bright can an eraser get? If I
were to
remove the innards of a 250W mercury-vapor bulb (leaving just the
quartz arc tube) and install that in an EPROM eraser (with suitable
ventilation), how long would it take to erase UV EPROMs? Would the
EPROMs survive?
I wonder if heat would become a problem before UV intensity.
-Dave
--
Dave McGuire
Port Charlotte, FL
12 Jun
12 Jun
8:19 p.m.
Bob Bradlee wrote:
usually the UV filter is in the lens / cover not the
cheep glass tube.
Though even if you remove the filter or lens, you still won't get that
much shortwave UV, because the bulb in those is usually in a glass
envelope, and glass blocks a lot of the shortwave UV. That's why tubes
made for shortwave UV, and the windows on EPROMs, are made of quartz
rather than normal glass.
Eric
14 Jun
14 Jun
5:05 p.m.
Eric Smith wrote:
Though even if you remove the filter or lens, you
still won't get that
much shortwave UV, because the bulb in those is usually in a glass
envelope, and glass blocks a lot of the shortwave UV. That's why tubes
made for shortwave UV, and the windows on EPROMs, are made of quartz
rather than normal glass.
I have a gadget which erases EPROMs using a flash tube. It is
the Dataman Strobe Eraser, and has a mains-powered flash tube
that's similar to a camera flash. You place the tube over the
EPROM window, pull the trigger and presumably test that the EPROM
has been erased. If not, give it another burst.
--
John Honniball
coredump at gifford.co.uk
15 Jun
15 Jun
3:54 p.m.
Eric Smith wrote:
I rememebr seeing adverts for that (and drooling over the S3 and S4
programmers, neither of which I could afford...)
Though even if you remove the filter or lens, you
still won't get that
much shortwave UV, because the bulb in those is usually in a glass
envelope, and glass blocks a lot of the shortwave UV. That's why tubes
made for shortwave UV, and the windows on EPROMs, are made of quartz
rather than normal glass.
I have a gadget which erases EPROMs using a flash tube. It is
the Dataman Strobe Eraser, and has a mains-powered flash tube that's similar to a camera flash. You place the
tube over the
You say it's _similar_ to a camera flash. Do you know of the discharge tube
is glass, or is it quartz, which would transmit more UV.
EPROM window, pull the trigger and presumably test
that the EPROM
has been erased. If not, give it another burst.
The electronics is presumanly pretty simple (even a battery-powered
version could, I think, be made with no more than 1 transistor). But if
the tube is special (as I suspect it is), making a similar device is a
non-starter.
-tony
13 Jun
13 Jun
6:06 p.m.
Bob Bradlee wrote:
On Fri, 12 Jun 2009 13:41:40 -0700, Eric Smith wrote:
That's kind of a problem, as regular glass absorbs most of the UV.
If you WANT the UV, you need a quartz bulb.
Warren
A regular camera flash is probably the wrong
thing to use, as by design
they don't emit a large amount of short-wave UV.
usually the UV filter is in the lens / cover not the cheep glass tube.
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