[Premium-Rx] Racal RA6778 firmware listing needed, and eprom longevity...

[Gary Geissinger]

Guys,

Peter is right on.

At my previous job a guy did the math on sunlight (and flourescent room
light) erasing 2708 EPROMs.

It looked like 30 days of direct sunlight or 2-3 years of lab lighting
will do the erase.  That was to meet the full erase spec.  I bet there
is degradation much sooner than that.

We did verify that the window must be covered during programming and use
on some EPROMS.  For example, the 'HC11 microcontroller with EPROM will
not program correctly in lab light if not covered.  And the output will
be wrong if operated in lab light as well.

Gary WA0SPM

   



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-----Original Message-----
From: premium-rx-bounces at ml.skirrow.org
[mailto:premium-rx-bounces at ml.skirrow.org] On Behalf Of Peter Gottlieb
Sent: Tuesday, May 10, 2005 9:12 AM
Cc: premium
Subject: Re: [Premium-Rx] Racal RA6778 firmware listing needed,and eprom
longevity...


I have not seen EPROMS get erased unintentionally, with two exceptions:

Those left on a desk in the sunlight without foil cover labels.

Those shipped overseas and subjected to neutron scanning (there were OTP
devices 
in epoxy packages!  We then tried to x-ray other OTP devices but it took
quite 
an exposure to completely clear them so apparently the neutron explosive

detection units are much more effective).

I suppose it is plausible that all the charge leaked out from yours but
I would 
think if it was a long term effect you would still see some data in
there.

It is easy enough to read out and save ERPOM data though, so long as the
devices 
are socketed and you take proper ESD precautions.

Peter


Dan Rae wrote:
> I recently bought one of these interesting receivers, which
> incidentally, must qualify as one of the earliest, if not the earliest

> Premium Rx, (Vintage late 1978) only to discover that it has lost one
of 
> the firmware eprom contents, and is thus totally dead, in other words
an 
> ex-radio.
> 
> I was aware that eproms could theoretically lose their contents with
> time, but this is the first time I've seen it at first hand.  I heard 
> that the early manufacturers of eproms only guaranteed them to retain 
> data for ten years.  In this case 25 plus years seems to have been 
> enough to do it.  The first of the three 2708 eproms in the radio
shows 
> all Fs...
> 
> So, I'm going to embark on a project to back up the contents of all 
> the
> eproms around here, in the older gear first, and there are a lot!  9
in 
> the hp 8903A, more in the 3586 and who knows what else until I start 
> looking?
> Meanwhile is there anyone who has a working one of these RA6778s , and

> it must be the A or B model, not the later C, who can help?  I have 
> eproms and a programmer, I just need the file to stuff in there.
> 
> And beware! Yours may be the next to die...
> 
> 73
> Dan
> ac6ao / g3ncr
> 
> 
> 
> 
> 
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