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Registered Member #27
Joined: Fri Feb 03 2006, 02:20AM
Location: Hyperborea
Posts: 2058
As far as I can tell Dr. Spark is talking about test equipment and not about chip packages but it is quite hard to decode the true meaning.
Here is a picture I took 5-6 years ago of one of those motherboard microcontrollers. Their main function was to handle the keyboard as far as I recall.
Registered Member #2123
Joined: Sat May 16 2009, 03:10AM
Location: Bend, Oregon
Posts: 312
In 1986 I was a Semiconductor Process Engineer (Photolithography/Wet Etch/Planarization) working for Applied Micro-Circuits Corporation (AMCC) in San Diego. I was part of the BiCMOS team that developed AMCC's 350MHz BiCMOS mixed-signal gate array family (introduced in 1989).
So how does RF cause electrons to quantum-tunnel away from a floating EPROM gate?
Registered Member #193
Joined: Fri Feb 17 2006, 07:04AM
Location: sheffield
Posts: 1022
The old-school way to erase them (if you didn't have a UV lamp, or time for the sun to do it) was to bake them in the oven. I can imagine RF heating works just fine.
Registered Member #96
Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4062
actually there is a mechanism for RF to work, but it requires there to be an inert gas inside the gap between the chip and case. the basic mechanism is that you apply HV at RF to the top of the casing above the chip and ground all the pins. if the field is sufficiently strong the gas ionises and wipes the chip in much the same way as uv does. the catch is that this doesen't do the chip much good but it can work when all else fails (esp. on stubborn 27Cxx chips with stuck bits)
interestingly those old chips often developed failed areas due to (presumably) "tired" cells. Worked fine once rewritten but the memory failed in weeks rather than years.
If you do ever see a failed chip and want to salvage the program one way is to read back at multiple voltages (5V, 4.4V and 4V) and see which bits change. Then it becomes a trivial exercise to determine which combination is correct :)
I've used a homemade emergency light + UVC tube before, worked fine. On the flip side those "UV toothbrush cleaners" ought to work, if anyone sees one in a sale.
-A "Bother" said Pooh, as he discovered giant hornets in his loft...
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