2114 Static RAMs...

From: Bill Sudbrink <wh.sudbrink_at_verizon.net>
Date: Sun Sep 12 20:45:53 2004

Dave Dunfield wrote:
> Tony Duell wrote:
> >> [If it is a 2114, it will be the second one I've found
> >> dead in PET hardware over the past month - other was
> >> was video RAM in a 4032]
> >
> >FWIW, I've had _lots_ of 2114s fail. I had to replace all
> >of them in my 8050 (IIRC, if you hvave multiple RAM errors,
> >you get the flash code for the lowest bank first, then when
> >you've replaced those you get the code for the next bank,
> >and so on...). I had to replace the video RAMs in my TRS-80
> >Model 3. And the RAM in my HP82163 video interface. And more...
> >
> >In my experiece the 2114 is one of the least reliable chips
> >ever...
> I've seen a few other ones fail as well - funny, I used a LOT
> of 2114s in my early building (at 4 bits each - way less
> wire-wrapping than 2102s). Never had any trouble with them at
> the time, however they do not seem to age well...

Another data point plus an "Arg!"...
Ohio Scientific was quite fond of 2114s (Arg!). It looks like
the cause of the power supply failure in my C4P is that one of
the 24K memory cards (48 2114s) was drawing well over spec, even
though it appeared to be providing reliable memory operation. It
was populated with the LC (low power CMOS) 2114 chip. According
to specs on the web, these should draw 40 milliamps max. I pulled
10 at random. Not one pulled less than 70. Now, I tested them
with all pins floating other than power and ground and I wonder
how much difference that makes, but totaling up an average of 75
per chip gives about what the card as a whole draws when in
operation. The other card, populated with another vendors 2114s,
draws over 1/2 amp less when in operation, reflecting about 42
milliamps per chip.
Received on Sun Sep 12 2004 - 20:45:53 BST

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