Replica IBM 5150 PC motherboard

Paul Berger phb.hfx at
Thu Mar 8 16:59:56 CST 2018

On 2018-03-08 6:49 PM, allison via cctalk wrote:
> On 03/08/2018 05:38 PM, Paul Berger via cctalk wrote:
>> Hmmmm I don't remember my original PC having all the chips in sockets
>> nor do I recall it having 64Kb DRAMs.  I clearly recall that it had
>> one bank of 16Kb DRAMs soldered down and sockets for three more banks
>> of 16Kb chips.  The only other sockets on the board where for the ROM,
>> CPU, and math coprocessor.  hardly a fathful reproduction.
>> Paul.
> Paul,
> That is the rev-b still 5150 but the next 4 digits are that hardware it was.
> your correct the first version only took 16k Drams x4 banks (64K).  It was
> very obvious that was way too little and a "few" revs were done to use 64K
> and later 256K parts.
> Personally why would any one want to build that?  It ran at 50% of what
> the 8088 could do in the day and was memory poor.  I know that as I was
> running a Multibus 8088 at 8mhz just as that was introduced.  That
> was faster.
> Allison
Ok I was not aware there was a second version I got mine in Nov. 81, and 
I agree who would really want one.  If you really wanted the 4.7MHz 
experience, I still see lots of PC and XTs go by on eBay.  I never did 
bother keeping a planar from an original PC, but have 2 from XTs.  One 
thing the original PC was useful for was the cassette interface on it 
could be used to emulate a TTY device for deaf people.  A long time ago 
I built a clone of it on a ISA bus card for a person that wanted to use 
it in an XT.


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