Jack ) wrote:
: You probably corrupted the EEPROM when you read it. I just learned about
: this when I was reading an article about security chips. If you try to read
: them with normal reader/writers, they get corrupted due to the fact that
: during the read process, the reader tries to write something on the chip, to
: test it out and this corrupts the chip.

I really don't think this is true of that family for the 93C46.

We used to used those things for something (think it was for alarm panels)
and although some in the family had the "protect bit", this "blowing of it"
to enable security only disabled reading the rom. Pretty sure you could sit
there all day and try reading it, nothing would happen.

It's a rather old device.

More likely the OP put it in wrong back into the socket, the socket itself
is bad or the socket into the circuit board. Maybe static discharge. I
really think it's a safe guess (although the datasheets have to be online
somewhere to prove it) that it has no "self destruct mode".

Pretty sure blowing the protect bit just internally disconnected the rom
address space from being accessed and sent out to the serial i/o.

-bruce