Is it possible to damage an EPROM by exposing it to UV light for too
long? What if a portion of the EPROM stays unprogrammed ('FF') and the
chip goes through some program-erase cycles? The unprogrammed area
should fail sooner or later, shouldn't it?

"Slater" wrote in message
...
Is it possible to damage an EPROM by exposing it to UV light for too
long? What if a portion of the EPROM stays unprogrammed ('FF') and the
chip goes through some program-erase cycles? The unprogrammed area
should fail sooner or later, shouldn't it?


The old ceramic packaged one's must be getting hard to find these days - can
flash ROMs be put in their place?

On 17 Aug 12 at group /sci/electronics/repair in article
(Jeff Liebermann) wrote:

It might be helpful if you disclosed the manufacturer and model
number.

Oh no, that`s an ultra secret: burn before reading!

SCNR



Saludos (an alle Vernünftigen, Rest sh. sig)
Wolfgang

--
Wolfgang Allinger, anerkannter Trollallergiker reply Adresse gesetzt!
Ich diskutiere zukünftig weniger mit Idioten, denn sie ziehen mich auf
ihr Niveau herunter und schlagen mich dort mit ihrer Erfahrung!
(lt. alter usenet Weisheit)

On Fri, 17 Aug 2012 18:05:29 GMT, (Slater) wrote:

Is it possible to damage an EPROM by exposing it to UV light for too
long?

No, and certainly not with a typical UV EPROM eraser with a typically
4watt UV lamp. Typical of most erasers is about 15mW/cm2 at 254nm for
15 minutes. Crank up the output much more and you'll smell ozone but
still won't burn out the EPROM. If the EPROM was manufactured using a
UV exposure masking process, typical UV levels during manufacture are
12watts/cm2.

What if a portion of the EPROM stays unprogrammed ('FF') and the
chip goes through some program-erase cycles? The unprogrammed area
should fail sooner or later, shouldn't it?

It's a bad EPROM. If the blank check on your unspecified EPROM burner
says it's not blank, it's not blank. The mostly likely culprit is
wrong settings on your unspecified model EPROM burner. It's also
possible for something in the circuit, or ESD to blow up the EPROM.
It's also possible that your unspecified EPROM burner has a weak UV
lamp and did not erase the entire EPROM. My favorite was having the
label peel off and stick to the lamp inside my Data-Erase cheapo
eraser. That cast a rather large shadow and caused numerous bad
erasures. I didn't find the label until I took it apart to replace
the lamp.

It might be helpful if you disclosed the manufacturer and model
number.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Friday, August 17, 2012 11:05:29 AM UTC-7, Slater wrote:

Is it possible to damage an EPROM by exposing it to UV light
for too long? What if a portion of the EPROM stays unprogrammed
('FF') and the chip goes through some program-erase cycles?
The unprogrammed area should fail sooner or later, shouldn't it?

I used only sunlight (Phoenix, AZ, 32N latitute, sky probably 90% clear), and for EPROMS written with all 0s, over 90% of the bits would erase in a day, 100% in 2 days, so I'd erase for 3-5 days. One summer I left a couple of EPROMs outside for a couple of months straight, and they all worked when I wrote all 0s to them, and the programming didn't take longer than for my other EPROMs, according to the programming method described in a TI data book, where a short programming pulse was used while the normal 5V supply went to 6V and the byte was tested after each write.

"Slater" wrote in message ...

Is it possible to damage an EPROM by exposing it to UV light for too
long? What if a portion of the EPROM stays unprogrammed ('FF') and the
chip goes through some program-erase cycles? The unprogrammed area
should fail sooner or later, shouldn't it?

I left some 25C64's In my manually controlled (that is, no timer) UV
eraser for a couple of weeks, when I forgot to turn it off. They all still
programmed and worked fine.

--
Lee K. Gleason N5ZMR
Control-G Consultants

On Fri, 17 Aug 2012 16:40:00 -0700 (PDT),
wrote:

I used only sunlight (Phoenix, AZ, 32N latitute, sky probably 90% clear),
and for EPROMS written with all 0s, over 90% of the bits would erase
in a day, 100% in 2 days, so I'd erase for 3-5 days.

In the late 1960's, I was working on a nifty new product that included
some of the first EPROMs. The prototype was done and the boss
declared that it was time to take a proper photograph for the product
release, manuals, promos, literature, etc. After the photographers
with their bright lights were done, I couldn't make it work. I
eventually determined that all the EPROMs had at least been partially
erased. My guess is about an hour under the very bright lights. I
didn't see the lights but suspect they could have been arc lamps as
incandescent lamps doesn't have enough UV content to erase EPROMs.
Installing a spare set of EPROMS got it working again. After that
experience, I made it a habit of putting labels over the EPROM window.



--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Jeff Liebermann wrote:

On Fri, 17 Aug 2012 16:40:00 -0700 (PDT),
wrote:

I used only sunlight (Phoenix, AZ, 32N latitute, sky probably 90% clear),
and for EPROMS written with all 0s, over 90% of the bits would erase
in a day, 100% in 2 days, so I'd erase for 3-5 days.

In the late 1960's, I was working on a nifty new product that included
some of the first EPROMs. The prototype was done and the boss
declared that it was time to take a proper photograph for the product
release, manuals, promos, literature, etc. After the photographers
with their bright lights were done, I couldn't make it work. I
eventually determined that all the EPROMs had at least been partially
erased. My guess is about an hour under the very bright lights. I
didn't see the lights but suspect they could have been arc lamps as
incandescent lamps doesn't have enough UV content to erase EPROMs.
Installing a spare set of EPROMS got it working again. After that
experience, I made it a habit of putting labels over the EPROM window.


_Foil_ labels. Paper sometimes wasn't opaque enough.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510
845-480-2058

hobbs at electrooptical dot net
http://electrooptical.net

On 8/17/2012 11:05 AM, Slater wrote:
Is it possible to damage an EPROM by exposing it to UV light for too
long?
yes
What if a portion of the EPROM stays unprogrammed ('FF') and the
chip goes through some program-erase cycles? The unprogrammed area
should fail sooner or later, shouldn't it?
yes

On Fri, 17 Aug 2012 21:45:44 -0400, Phil Hobbs
wrote:

Jeff Liebermann wrote:

On Fri, 17 Aug 2012 16:40:00 -0700 (PDT),
wrote:

I used only sunlight (Phoenix, AZ, 32N latitute, sky probably 90% clear),
and for EPROMS written with all 0s, over 90% of the bits would erase
in a day, 100% in 2 days, so I'd erase for 3-5 days.

In the late 1960's, I was working on a nifty new product that included
some of the first EPROMs. The prototype was done and the boss
declared that it was time to take a proper photograph for the product
release, manuals, promos, literature, etc. After the photographers
with their bright lights were done, I couldn't make it work. I
eventually determined that all the EPROMs had at least been partially
erased. My guess is about an hour under the very bright lights. I
didn't see the lights but suspect they could have been arc lamps as
incandescent lamps doesn't have enough UV content to erase EPROMs.
Installing a spare set of EPROMS got it working again. After that
experience, I made it a habit of putting labels over the EPROM window.


_Foil_ labels. Paper sometimes wasn't opaque enough.

Agreed. I still have a lifetime supply of 5 1/4" floppy disk write
protect tabs. Most are black vinyl(?) or some opaque black plastic
over paper. They go on easily, and remove without leaving a mess.

Incidentally, I just remmembered that I once won an arguement whether
a stick arc welder will erase an EPROM. An Intel 2764 was used
because I had plenty of them. My guess is that it takes about 2
minutes of exposure to trash the EPROM and about 10 minutes to totally
erase it. Keeping an arc going for 10 minutes was impossible, but 15
seconds at a time was easy enough. I also managed to get slag on
every EPROM, but that was expected.

When I tried to use some of the test EPROMs later, I found that I had
zapped some cells. I don't know how I did that since I shoved the
leads into a crumpled block of aluminum foil.

Assuming 200A at about 10V across the arc, that's 2000 watts. My wild
guess is about 1/10th of that is UV. Assuming a spherical radiation
pattern, a distance of about 10 cm, and an old EPROM chip size of 0.25
cm^2 chip area, the UV power density is very roughly:
Surface area of sphere =
4 Pi r^2 = 4 * 3.14 * 10cm^2 = 1256 cm^2
Power density
= 2000 watts / 1256 cm^2 / 0.25 * 1/10 = 0.64 watts/cm^2
That's 130 times the UV that's delivered by the typical 15mw EPROM
eraser. I would have expected it to erase the EPROM 130 times faster,
but that didn't happen.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Sat, 18 Aug 2012 00:19:28 -0700, Jeff Liebermann wrote:

Incidentally, I just remmembered that I once won an arguement whether a
stick arc welder will erase an EPROM. An Intel 2764 was used because I
had plenty of them. My guess is that it takes about 2 minutes of
exposure to trash the EPROM and about 10 minutes to totally erase it.
Keeping an arc going for 10 minutes was impossible, but 15 seconds at a
time was easy enough. I also managed to get slag on every EPROM, but
that was expected.

Somewhere in the 80s I salvaged a proprietary controller in a steel sheet
cutting machine using this. We were rushing a repair late at night in the
middle of nowhere in France. About three sticks managed to wipe 8 devices.
It needed some convincing the customer though, he believed I was joking.
The nicest part was the French cuisine afterwards ;-)

Jeff Liebermann wrote:

What if a portion of the EPROM stays unprogrammed ('FF') and the
chip goes through some program-erase cycles? The unprogrammed area
should fail sooner or later, shouldn't it?

It's a bad EPROM. If the blank check on your unspecified EPROM burner
says it's not blank, it's not blank.

I meant another thing: what will happen if a chip undergoes several
write/erase cycles where an area is intentionally left unprogrammed
every time? It's like erasing it over and over.
Probably nothing, I think. It must have happened quite often that some
byte (or bit, why not?) would always be unprogrammed at every cycle in
the prototyping process, so it shouln't be a problem.

On Sat, 18 Aug 2012 18:10:08 GMT, (Slater) wrote:

Jeff Liebermann wrote:

What if a portion of the EPROM stays unprogrammed ('FF') and the
chip goes through some program-erase cycles? The unprogrammed area
should fail sooner or later, shouldn't it?

It's a bad EPROM. If the blank check on your unspecified EPROM burner
says it's not blank, it's not blank.

I meant another thing: what will happen if a chip undergoes several
write/erase cycles where an area is intentionally left unprogrammed
every time? It's like erasing it over and over.

Nothing will happen. Erasing sets all the bits to a "1". If the bits
are already set to "1", then erasing won't change or wreck the bit.

EPROMs do have a limited number of erase cycles. It really depends on
the age and technology of your unspecified EPROM. Usually it's about
1000 erase cycles before the silicon dioxide wrapped around the gate
falls apart.

Probably nothing, I think. It must have happened quite often that some
byte (or bit, why not?) would always be unprogrammed at every cycle in
the prototyping process, so it shouln't be a problem.

Well, there's an easy test. Erase your unspecified EPROM. Verify
that every byte is set to FF with the blank check on your unspecified
model EPROM eraser. Create a bin file where all the bytes are
programmed to "OO". Write the file to the EPROM and compare the bin
file with a read from the EPROM. If they're identical, then the
programmer was able to change every cell and there are no bits stuck
at "1". If there are any bytes NOT set to "00", you have at least one
stuck bit.



--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Jeff Liebermann wrote:
Well, there's an easy test. Erase your unspecified EPROM. Verify
that every byte is set to FF with the blank check on your unspecified
model EPROM eraser. Create a bin file where all the bytes are
programmed to "OO". Write the file to the EPROM and compare the bin
file with a read from the EPROM. If they're identical, then the
programmer was able to change every cell and there are no bits stuck
at "1". If there are any bytes NOT set to "00", you have at least one
stuck bit.

Joining this late, I want to mention that the 27C series EPROMS can still
be bought. You can buy them from China for about $2 each including postage
for erased and tested "pulls" and new ones can be had for around $45.

They even come in the small flat packages that are common these days.
(sorry, it's late at night, and I don't remember their name)

I specifically needed 27C256's and 27C512's, last summer, so I bought an
eraser for around $15, a USB programmer for under $50 (including the adaptor
for flat packaged chips) and a bunch of $2 chips.

The eraser was an odd combination of a 230 volt unit with a US 120 volt plug,
and a mechanincal timer with a separate on off switch. I replaced the plug
with one more appropriate for my needs and just leave the timer in the
always on position, using an electronic kitchen timer and the on/off switch.

Geoff.


--
Geoffrey S. Mendelson, N3OWJ/4X1GM/KBUH7245/KBUW5379

On Friday, August 17, 2012 11:05:29 AM UTC-7, Slater wrote:
Is it possible to damage an EPROM by exposing it to UV light for too

long?

Yes, sometimes. The reason is, EPROM designs sometimes use
difference amplifiers with dummy cells that are factory-programmed
and covered with a light-tight lid. So, if enough light leaks around
the lid, the bias of the sense amplifiers changes (and the chip can
become incapable of proper readout).

It's a matter of bleaching out the bias current sources...

On Sat, 18 Aug 2012 22:04:03 +0000 (UTC), "Geoffrey S. Mendelson"
wrote:

Joining this late, I want to mention that the 27C series EPROMS can still
be bought. You can buy them from China for about $2 each including postage
for erased and tested "pulls" and new ones can be had for around $45.

Yep. I just stocked up on 27C512 EPROMS (for Kantronics TNC's) at
about $1.50/ea it took about 2 weeks to arrive. All 20 were good.
However, I had to peel the original labels and UV erase them.

They even come in the small flat packages that are common these days.
(sorry, it's late at night, and I don't remember their name)

Atmel or Winbond AT27C512
http://www.ebay.com/itm/330561223626

I specifically needed 27C256's and 27C512's, last summer, so I bought an
eraser for around $15, a USB programmer for under $50 (including the adaptor
for flat packaged chips) and a bunch of $2 chips.

I have a Willem version 5.0 programmer.
http://www.ebay.com/itm/370640611286
Highly recommended. There's also the 6.0 version, which allegedly has
more features and requires fewer adapters:
http://www.ebay.com/itm/221106449319

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Ian Field wrote:


"Slater" wrote in message
...
Is it possible to damage an EPROM by exposing it to UV light for too
long? What if a portion of the EPROM stays unprogrammed ('FF') and the
chip goes through some program-erase cycles? The unprogrammed area
should fail sooner or later, shouldn't it?


The old ceramic packaged one's must be getting hard to find these days - can
flash ROMs be put in their place?

how long can those old ceramic+window things keep their memory? Some spec
sheets indicate some random number of decades, but is any of this true?

"Cydrome Leader" wrote in message
...
Ian Field wrote:


"Slater" wrote in message
...
Is it possible to damage an EPROM by exposing it to UV light for too
long? What if a portion of the EPROM stays unprogrammed ('FF') and the
chip goes through some program-erase cycles? The unprogrammed area
should fail sooner or later, shouldn't it?


The old ceramic packaged one's must be getting hard to find these days -
can
flash ROMs be put in their place?

how long can those old ceramic+window things keep their memory? Some spec
sheets indicate some random number of decades, but is any of this true?


I have an old XT-turbo clone with UV EPROMs that still works.

Cydrome Leader wrote in
:

Ian Field wrote:


"Slater" wrote in message
...
Is it possible to damage an EPROM by exposing it to UV light for too
long? What if a portion of the EPROM stays unprogrammed ('FF') and
the chip goes through some program-erase cycles? The unprogrammed
area should fail sooner or later, shouldn't it?


The old ceramic packaged one's must be getting hard to find these
days - can flash ROMs be put in their place?

how long can those old ceramic+window things keep their memory? Some
spec sheets indicate some random number of decades, but is any of this
true?



Two BBC2 computers and an ARC310 with numerous chips loaded with
software have survived 20+ years, and still going strong.

Cydrome Leader wrote in
:

Ian Field wrote:


"Slater" wrote in message
...
Is it possible to damage an EPROM by exposing it to UV light for too
long? What if a portion of the EPROM stays unprogrammed ('FF') and
the chip goes through some program-erase cycles? The unprogrammed
area should fail sooner or later, shouldn't it?


The old ceramic packaged one's must be getting hard to find these
days - can flash ROMs be put in their place?

how long can those old ceramic+window things keep their memory? Some
spec sheets indicate some random number of decades, but is any of this
true?



flash memory(NOT a "ROM" aka Read-Only Memory) is not going to have the
same pinouts,because one pin has to have the write enable command that a
PROM lacks.

--
Jim Yanik
jyanik
at
localnet
dot com

"Jim Yanik" wrote in message
4...
Cydrome Leader wrote in
:

Ian Field wrote:


"Slater" wrote in message
...
Is it possible to damage an EPROM by exposing it to UV light for too
long? What if a portion of the EPROM stays unprogrammed ('FF') and
the chip goes through some program-erase cycles? The unprogrammed
area should fail sooner or later, shouldn't it?


The old ceramic packaged one's must be getting hard to find these
days - can flash ROMs be put in their place?

how long can those old ceramic+window things keep their memory? Some
spec sheets indicate some random number of decades, but is any of this
true?



flash memory(NOT a "ROM" aka Read-Only Memory) is not going to have the
same pinouts,because one pin has to have the write enable command that a
PROM lacks.

If supply of ceramic cased UV window types dries up; pinout converter PCBs
may be the only option - the peculiarities of addressing and write command
sequencing only concern the programming device, not the application PCB.

On Aug 25, 11:11*pm, Cydrome Leader wrote:


how long can those old ceramic+window things keep their memory? Some spec
sheets indicate some random number of decades, but is any of this true?

I have arcade machine boards going back to 1978 that used eproms that
are running fine.

You can still find just about any type of eprom (Even 2708s and those
triple supply TMS varieties) as NOS if you know where to look.

On Sun, 26 Aug 2012 03:11:43 +0000 (UTC), Cydrome Leader
wrote:

Ian Field wrote:


"Slater" wrote in message
...
Is it possible to damage an EPROM by exposing it to UV light for too
long? What if a portion of the EPROM stays unprogrammed ('FF') and the
chip goes through some program-erase cycles? The unprogrammed area
should fail sooner or later, shouldn't it?


The old ceramic packaged one's must be getting hard to find these days - can
flash ROMs be put in their place?

how long can those old ceramic+window things keep their memory? Some spec
sheets indicate some random number of decades, but is any of this true?

I have a Fanuc 5T CNC control built in 1974 that has a bunch of those
ceramic EPROMS in it. They still work fine. However, I had another
identical control, made one month before, that had a few EPROMS fail
about 10 years ago.
Eric

har bragt dette til verden:
On Friday, August 17, 2012 11:05:29 AM UTC-7, Slater wrote:

Is it possible to damage an EPROM by exposing it to UV light
for too long? What if a portion of the EPROM stays unprogrammed
('FF') and the chip goes through some program-erase cycles?
The unprogrammed area should fail sooner or later, shouldn't it?

I used only sunlight (Phoenix, AZ, 32N latitute, sky probably 90% clear),

It never worked for me in Denmark, 56N

--
Husk kørelys bagpå, hvis din bilfabrikant har taget den idiotiske
beslutning at undlade det.

Leif Neland wrote:

har bragt dette til verden:
On Friday, August 17, 2012 11:05:29 AM UTC-7, Slater wrote:

Is it possible to damage an EPROM by exposing it to UV light
for too long? What if a portion of the EPROM stays unprogrammed
('FF') and the chip goes through some program-erase cycles?
The unprogrammed area should fail sooner or later, shouldn't it?

I used only sunlight (Phoenix, AZ, 32N latitute, sky probably 90% clear),

It never worked for me in Denmark, 56N


You are replying to a three month old message.

On 11/24/2012 5:20 PM, Leif Neland wrote:
har bragt dette til verden:
On Friday, August 17, 2012 11:05:29 AM UTC-7, Slater wrote:

Is it possible to damage an EPROM by exposing it to UV light for too
long? What if a portion of the EPROM stays unprogrammed ('FF') and
the chip goes through some program-erase cycles? The unprogrammed
area should fail sooner or later, shouldn't it?

I used only sunlight (Phoenix, AZ, 32N latitute, sky probably 90% clear),

It never worked for me in Denmark, 56N

It's an old thread, but I have a story and some time on my hands.

The erase is not the only problem. Charge can leak in or out
electrically too.
I had a TEK 308 logic analyzer that wouldn't run. I fixed it
by reading the EPROM in my reader, erasing it and putting the
same bits back in. The data was marginal and wouldn't run
at speed, but the programmer was slow enough that it worked.
I replaced the chip anyway.

The Compaq Aero laptops had a recurrent "motherboard failure".
I discovered that you could pull the EEPROM, read it
and reprogram it with the same data. That fixed it for
a random length of time. In that case, I think the cause
was that the program line was left floating. Some combination
of turnon/off transients let random "puffs" of charge into
whatever address happened to be on the pins and the thresholds
shifted over time until it failed to boot. I fixed several of them
by reprogramming. Replacing the chip didn't help.

I like the roadway analogy.
Spread gravel on a road. By the end of rush hour, there won't
be any gravel in the path of the tires. When a tire hits a bit of gravel,
it causes it to move in some random direction. If that direction
takes it out of the tire path, it quits moving. Statistically,
all the gravel eventually gets displaced out of the tire path.
The gravel got erased.
But the tires also damage the road. Bits of gravel get embedded
in the roadway and can't move out. Eventually, the roadway turns
to gravel and can't support the traffic. Getting just the right
amount of energy is critical for maximum life. That's why they
don't want you to drive a tank down a residential street.

Michael A. Terrell kom med denne ide:
Leif Neland wrote:

har bragt dette til verden:
On Friday, August 17, 2012 11:05:29 AM UTC-7, Slater wrote:

Is it possible to damage an EPROM by exposing it to UV light
for too long? What if a portion of the EPROM stays unprogrammed
('FF') and the chip goes through some program-erase cycles?
The unprogrammed area should fail sooner or later, shouldn't it?

I used only sunlight (Phoenix, AZ, 32N latitute, sky probably 90% clear),

It never worked for me in Denmark, 56N


You are replying to a three month old message.

I know.

I still have 1500 out of 9000 messages to read, but I'm catching up :-)

Leif

--
Husk kørelys bagpå, hvis din bilfabrikant har taget den idiotiske
beslutning at undlade det.

"Leif Neland" wrote in message
...
Michael A. Terrell kom med denne ide:
Leif Neland wrote:

har bragt dette til verden:
On Friday, August 17, 2012 11:05:29 AM UTC-7, Slater wrote:

Is it possible to damage an EPROM by exposing it to UV light
for too long? What if a portion of the EPROM stays unprogrammed
('FF') and the chip goes through some program-erase cycles?
The unprogrammed area should fail sooner or later, shouldn't it?

I used only sunlight (Phoenix, AZ, 32N latitute, sky probably 90%
clear),

It never worked for me in Denmark, 56N


You are replying to a three month old message.

I know.

I still have 1500 out of 9000 messages to read, but I'm catching up :-)


And there was us thinking you'd accidently reversed the "sent"
ascending/descending arrow and not noticed.

"mike" wrote in message
...
On 11/24/2012 5:20 PM, Leif Neland wrote:
har bragt dette til verden:
On Friday, August 17, 2012 11:05:29 AM UTC-7, Slater wrote:

Is it possible to damage an EPROM by exposing it to UV light for too
long? What if a portion of the EPROM stays unprogrammed ('FF') and
the chip goes through some program-erase cycles? The unprogrammed
area should fail sooner or later, shouldn't it?

I used only sunlight (Phoenix, AZ, 32N latitute, sky probably 90%
clear),

It never worked for me in Denmark, 56N

It's an old thread, but I have a story and some time on my hands.

The erase is not the only problem. Charge can leak in or out electrically
too.
I had a TEK 308 logic analyzer that wouldn't run. I fixed it
by reading the EPROM in my reader, erasing it and putting the
same bits back in. The data was marginal and wouldn't run
at speed, but the programmer was slow enough that it worked.
I replaced the chip anyway.

The Compaq Aero laptops had a recurrent "motherboard failure".
I discovered that you could pull the EEPROM, read it
and reprogram it with the same data. That fixed it for
a random length of time. In that case, I think the cause
was that the program line was left floating. Some combination
of turnon/off transients let random "puffs" of charge into
whatever address happened to be on the pins and the thresholds
shifted over time until it failed to boot. I fixed several of them
by reprogramming. Replacing the chip didn't help.

I like the roadway analogy.
Spread gravel on a road. By the end of rush hour, there won't
be any gravel in the path of the tires. When a tire hits a bit of gravel,
it causes it to move in some random direction. If that direction
takes it out of the tire path, it quits moving. Statistically,
all the gravel eventually gets displaced out of the tire path.
The gravel got erased.
But the tires also damage the road. Bits of gravel get embedded
in the roadway and can't move out. Eventually, the roadway turns
to gravel and can't support the traffic. Getting just the right
amount of energy is critical for maximum life. That's why they
don't want you to drive a tank down a residential street.


I'm a motorcyclist - I'd drive the tank along the line of parked cars.

Leif Neland wrote:

Michael A. Terrell kom med denne ide:
Leif Neland wrote:

har bragt dette til verden:
On Friday, August 17, 2012 11:05:29 AM UTC-7, Slater wrote:

Is it possible to damage an EPROM by exposing it to UV light
for too long? What if a portion of the EPROM stays unprogrammed
('FF') and the chip goes through some program-erase cycles?
The unprogrammed area should fail sooner or later, shouldn't it?

I used only sunlight (Phoenix, AZ, 32N latitute, sky probably 90% clear),

It never worked for me in Denmark, 56N


You are replying to a three month old message.

I know.

I still have 1500 out of 9000 messages to read, but I'm catching up :-)


9000? I see a total of 237,016 messages for this group.

Ian Field wrote:

I'm a motorcyclist - I'd drive the tank along the line of parked cars.


Hopefully, someone will have a couple M-72 and a cutting torch. Or
several thermite grenades to weld the hatch shut.

Michael A. Terrell forklarede den 25-11-2012:
Leif Neland wrote:

Michael A. Terrell kom med denne ide:
Leif Neland wrote:

har bragt dette til verden:
On Friday, August 17, 2012 11:05:29 AM UTC-7, Slater wrote:

Is it possible to damage an EPROM by exposing it to UV light
for too long? What if a portion of the EPROM stays unprogrammed
('FF') and the chip goes through some program-erase cycles?
The unprogrammed area should fail sooner or later, shouldn't it?

I used only sunlight (Phoenix, AZ, 32N latitute, sky probably 90% clear),

It never worked for me in Denmark, 56N


You are replying to a three month old message.

I know.

I still have 1500 out of 9000 messages to read, but I'm catching up :-)


9000? I see a total of 237,016 messages for this group.

I only wanted to go back one year, when I discovered this group.

--
Husk kørelys bagpå, hvis din bilfabrikant har taget den idiotiske
beslutning at undlade det.

Leif Neland wrote:

Michael A. Terrell wrote:

9000? I see a total of 237,016 messages for this group.

I only wanted to go back one year, when I discovered this group.


The 237,019 messages is only back to 2003. I've been around here
since 1998

"Michael A. Terrell" wrote in message
m...

Ian Field wrote:

I'm a motorcyclist - I'd drive the tank along the line of parked cars.


Hopefully, someone will have a couple M-72 and a cutting torch. Or
several thermite grenades to weld the hatch shut.


Its a fair bet you're the kind of car driver that makes motorcyclists want
to drive a tank over a line of parked cars.

Ian Field wrote:

"Michael A. Terrell" wrote in message
m...

Ian Field wrote:

I'm a motorcyclist - I'd drive the tank along the line of parked cars.


Hopefully, someone will have a couple M-72 and a cutting torch. Or
several thermite grenades to weld the hatch shut.


Its a fair bet you're the kind of car driver that makes motorcyclists want
to drive a tank over a line of parked cars.


As always, you show everyone what an ass you are.


There are some bikers weave in and out of traffic without concern for
other drivers, and ride in other driver's blind spots. Most bikers are
decent people and careful drivers, but the small group of assholes makes
most people not give a damn.

The only time I came close to hitting a biker was when some ass in a
tiny import pulled out in front of me on a highway from a side street
and I was doing the posted 55 MPH. A left turn on red in front of a
truck. No room to brake and nothing in the mirrors, so I changed lanes
and hear a horn squalling tires & brakes. The biker had been in my
right side blind spot for several minutes, and just barely missed the
back of my truck. He appologized, and admitted he was riding in the
wrong position because he wasn't paying attention. That's once, in 42
years.

If an asshole drove a tank over cars he is a terrorist. Someone
should weld him in the tank, and set off enough thermite grenades to
make sure it won't move again. Or open the port and fill it with
burning Napalm to be sure they never commit another act of terrorism.

"Michael A. Terrell" wrote in message
m...

Ian Field wrote:

"Michael A. Terrell" wrote in message
m...

Ian Field wrote:

I'm a motorcyclist - I'd drive the tank along the line of parked cars.


Hopefully, someone will have a couple M-72 and a cutting torch. Or
several thermite grenades to weld the hatch shut.


Its a fair bet you're the kind of car driver that makes motorcyclists
want
to drive a tank over a line of parked cars.


As always, you show everyone what an ass you are.


There are some bikers weave in and out of traffic without concern for
other drivers, and ride in other driver's blind spots. Most bikers are
decent people and careful drivers, but the small group of assholes makes
most people not give a damn.

The only time I came close to hitting a biker was when some ass in a
tiny import pulled out in front of me on a highway from a side street
and I was doing the posted 55 MPH. A left turn on red in front of a
truck. No room to brake and nothing in the mirrors, so I changed lanes
and hear a horn squalling tires & brakes.

You obviously weren't paying due care & attention to get caught out like
that, you can't blame the motorcyclist for distracting you as you already
admitted you didn't know he was there.

I've driven cars, and I can tell you from experience - it really isn't
difficult to know what's behind you!

Ian Field wrote:

"Michael A. Terrell" wrote in message
m...

Ian Field wrote:

"Michael A. Terrell" wrote in message
m...

Ian Field wrote:

I'm a motorcyclist - I'd drive the tank along the line of parked cars.


Hopefully, someone will have a couple M-72 and a cutting torch. Or
several thermite grenades to weld the hatch shut.


Its a fair bet you're the kind of car driver that makes motorcyclists
want
to drive a tank over a line of parked cars.


As always, you show everyone what an ass you are.


There are some bikers weave in and out of traffic without concern for
other drivers, and ride in other driver's blind spots. Most bikers are
decent people and careful drivers, but the small group of assholes makes
most people not give a damn.

The only time I came close to hitting a biker was when some ass in a
tiny import pulled out in front of me on a highway from a side street
and I was doing the posted 55 MPH. A left turn on red in front of a
truck. No room to brake and nothing in the mirrors, so I changed lanes
and hear a horn squalling tires & brakes.

You obviously weren't paying due care & attention to get caught out like
that, you can't blame the motorcyclist for distracting you as you already
admitted you didn't know he was there.


He admitted he was riding in my blind spot, and you say he wasn't
Who am I to believe?


I've driven cars, and I can tell you from experience - it really isn't
difficult to know what's behind you!


So, you have _never_ had a blind spot on _any_ vehicle? I suppose
you have a couple slightly used bridges for sale, too?

"Michael A. Terrell" wrote in message
...

Ian Field wrote:

"Michael A. Terrell" wrote in message
m...

Ian Field wrote:

"Michael A. Terrell" wrote in message
m...

Ian Field wrote:

I'm a motorcyclist - I'd drive the tank along the line of parked
cars.


Hopefully, someone will have a couple M-72 and a cutting torch.
Or
several thermite grenades to weld the hatch shut.


Its a fair bet you're the kind of car driver that makes motorcyclists
want
to drive a tank over a line of parked cars.


As always, you show everyone what an ass you are.


There are some bikers weave in and out of traffic without concern for
other drivers, and ride in other driver's blind spots. Most bikers are
decent people and careful drivers, but the small group of assholes
makes
most people not give a damn.

The only time I came close to hitting a biker was when some ass in a
tiny import pulled out in front of me on a highway from a side street
and I was doing the posted 55 MPH. A left turn on red in front of a
truck. No room to brake and nothing in the mirrors, so I changed lanes
and hear a horn squalling tires & brakes.

You obviously weren't paying due care & attention to get caught out like
that, you can't blame the motorcyclist for distracting you as you already
admitted you didn't know he was there.


He admitted he was riding in my blind spot, and you say he wasn't
Who am I to believe?


I've driven cars, and I can tell you from experience - it really isn't
difficult to know what's behind you!


So, you have _never_ had a blind spot on _any_ vehicle? I suppose
you have a couple slightly used bridges for sale, too?

I didn't say there were never blind spots - just, unlike you I know how to
drive with due consideration for other road users.

Ian Field wrote:

I didn't say there were never blind spots - just, unlike you I know how to
drive with due consideration for other road users.


You don't know a damn thing about me or anyone else on this group,
but you want to make people think you do. I've been driving 42 years
and was in one wreck, when a woman came across the center line & hit me
head on. My choice was to let her hit me, of drop off the road into a
deep ditch. I also backed into an MG midget when a semi back out out in
front of me. Instead of backing up when my backup lights came on, he
waited till I rolled 18 inches and hit him. Not visible in any mirror,
because he was in a triple blind spot. He squalled tires to back up,
then came running up to my truck demanding that I get out and fight him,
wile the semi trailer was coming towards us. He was so stupid that he
almost got backed over by a semi trailer load of cardboard boxes.
Plenty off signs that it was an industrial zone and to watch for big
rigs, but the self important little prick thought _he_ knew how to
drive. There were no marks on his car, so he jumped in it and took off
after the road cleared and passed the semi on a double yellow line.


I've been through multiple safe driving courses, including for large
military trucks. One was on an iced over parking lot for ice road
driving in Alaska.

Only a fool will make your claim, because a bike or small car can
slip into your blind spot when you are looking forward. No matter how
often you check the mirrors, you won't see them if they ignore the rules
of the road. That's why large trucks & buses have warning signs to
remind the idiots. Why else would they say, "If you can't see my mirror
- I can't see you." I owned & drove a step van for over a decade.
That's 24 feet, bumper to bumper. Over three tons with just side
mirrors. It was amazing the number of fools who would follow so close
that you couldn't see them in either mirror, but you'd hear their horn
when you had to hit the brakes. The absolute worst drivers here are the
foreigners who rent a car and ignore all US traffic laws.

http://static.seton.com/media/catalog/product/Truck-Safety-Signs-7258A-001-ba.gif

"Michael A. Terrell" wrote in message
...

Ian Field wrote:

"Michael A. Terrell" wrote in message
m...

Ian Field wrote:

"Michael A. Terrell" wrote in message
m...

Ian Field wrote:

I'm a motorcyclist - I'd drive the tank along the line of parked
cars.


Hopefully, someone will have a couple M-72 and a cutting torch.
Or
several thermite grenades to weld the hatch shut.


Its a fair bet you're the kind of car driver that makes motorcyclists
want
to drive a tank over a line of parked cars.


As always, you show everyone what an ass you are.


There are some bikers weave in and out of traffic without concern for
other drivers, and ride in other driver's blind spots. Most bikers are
decent people and careful drivers, but the small group of assholes
makes
most people not give a damn.

The only time I came close to hitting a biker was when some ass in a
tiny import pulled out in front of me on a highway from a side street
and I was doing the posted 55 MPH. A left turn on red in front of a
truck. No room to brake and nothing in the mirrors, so I changed lanes
and hear a horn squalling tires & brakes.

You obviously weren't paying due care & attention to get caught out like
that, you can't blame the motorcyclist for distracting you as you already
admitted you didn't know he was there.


He admitted he was riding in my blind spot, and you say he wasn't
Who am I to believe?

No I didn't, and since your blind spot is 360 degrees how could he possibly
deny being in it.

For a sighted person the blind spots are where you make them.

When changing lane you need to look behind in the lane you're cutting into -
not the one you're leaving.

The nearest I got to getting wiped out in recent years was some **** not
paying attention on the approach to a busy junction - I was minding my own
business in the turning lane when he suddenly lurched into it alongside me,
apparently to avoid slamming into a broken down car he hadn't noticed till
the last second.

The amazing thing was, the police were right behind me at the time - seconds
later they were right behind him with lights & siren going.