Re: Todd's ELF-ish gets some more Memory #ELF #Homebrew


On Sat, May 11, 2019 at 03:35 PM, Lee Hart wrote:
taf123 wrote:
Although I've never seen RCA 89052 anywhere, the RCA manual for this
Microboard says that the replacement part is the MWS5114. Looking at
the supplied schematic, the chips are pin-compatible. The 5114
obviously has one more address-line, but that pin is tied LO on this
board, so the 5114 would just function like a 512 x 4-bit memory.
I suspect that the 89052's were MW5114's that had a bad bit. Rather than
throw them out (RAMs were expensive back then!), they used them as
512-byte RAMs.
That makes a lot of sense - I wouldn't be at all surprised.

I hope to attempt a repair of this board in the near future - updates to
this forum when that happens.
I have a tube of RCA MW5114's if you (or others) need any. I also have a
couple tubes of 5101's (some RCA, some NEC). :-)
Thanks for the offer, but as I wrote that up, I did an eBay search for some more MWS5114's and already placed an order.

Bad timing ;-)  Sometimes, this Internet thing can be too efficient.

Best regards,

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