IBM 5161

From: Witchy <>
Date: Fri Apr 4 12:19:01 2003

> -----Original Message-----
> From: []On
> Behalf Of Bill Allen Jr
> Sent: 02 April 2003 06:14
> To:
> Subject: RE: IBM 5161
> The ibm 5161 expansion box was designed for use with
> the ibm pc.

And presumably *only* the PC, ie not the XT.

> the pc had fewer slots then the later released pc xt
> and it's power supply was too small to handle a hard
> drive.

Yep, 5 slots and a 63W PSU that couldn't even handle a fully populated
backplane if some of the cards were a little power-hungry.

> the exp box added a hard drive to the system and
> provided extra card slots ( i think the box also had
> additional bios or came with an extra fixed disk rom
> chip that went into the pc).

Not that I've found, just an 8-slot backplane which immediately loses a slot
because one of them must be occupied by the receiving end of the expander
interface that has to go in the 5150. There might be a BIOS in that
interface though, I didn't really check that. The 5161 has a hard drive
controller card in it as well as a Seagate monster that's probably only 5 or
10 meg.

> the card that connects to the ribbon cables that come
> from the exp box goes into one of the pc's card slots.

No ribbon cables, just an interface cable that's thicker than my thumb!

> i cannot remember if it is slot specific or if it can
> go into any slot - there is a plate on the pc's back
> that removes to allow the ribbon cables to exit the
> case.

There's a plate on the back, yes, maybe very early boxes used ribbons and
the thicker cables came along later?

> i was told that the expansion box was a little rare
> because, shortly after the pc was released that pc xt
> was released .

Well, a year later anyway, after the 5150 had shifted 200,000 units
according to most websites.

I've put a breakdown of the kit on my IBM page - go to and click on the link in the very top 'updates'


adrian/witchy - the online computer museum - monthly gothic shenanigans
Received on Fri Apr 04 2003 - 12:19:01 BST

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