[sdiy] Nasty Bits in EPROM

[Jim Patchell]

    I use a lot of  27c010's at the moment.  One thing I have noticed is that I
get a lot more failures with eproms now than I did in the past.  They don't seem
to be quite as rugged as they once were.  Although, the last batch I killed, I
had left in the eraser over the weekend (ooooppppsss!).  All of them were
definately erased, but they seemed to be erased permanently (they would no
longer program).  But, my biggest problem is ESD (or, so it seems).  As long as
I follow proper handling proceedures, everything is OK.  When I fundge, I begin
getting parts that fail in various ways after just a few programming cycles.
But 5 years ago, I used to treat the 27c010's pretty badly.  I had parts that
were several years old (and probably about 1000 cycles on them), that were still
going strong.  These days, the average life of an eprom is about 1 month (I am
talking about the ones I use for developement, I keep threatening to get a ROM
emulator, but erasing an programming proms still hasn't annoyed me enough).

    -Jim

Rob wrote:

> Anyone ever have a UV EPROM that just will NOT erase completely? I always
> seem to have a bit that says FB, but its not at the same address every time.
> I dled the rom image and did a search, and I find FB in 2-3 places, but
> after UVing them, the addresses change!!
>
> In all the hundreds of eproms I have UVd, then reprogged, then UVd again
> over and over, I have never in all the thousands found one do this.
>
> Arrgh!! I hate when stupid things like this happen..
>
> Rob
> CyborgZero Technologies
> www.angelfire.com/il/cyborgzerotech
> AIM:cyborgzr0 <--- that last thing is a number
> repairs/mods/retrofits