8 Mar
2025
8 Mar
'25
9:35 p.m.
On Sat, Mar 8, 2025 at 7:25 PM Mike Katz via cctalk
<cctalk(a)classiccmp.org> wrote:
The HP Portable Plus computer ROM Drawer uses 28 pin 1MBit (128K) Mask
ROMs (TC531000) or 512KBit EPROMs (27C512).
A few years ago a company called Personalized Software made something
called a ROMBO. This was an adapter that allowed the use of a 32 Pin
27C010 Quad Pack and plugged into the 28 pin socket on the ROM Drawer.
The down side of this was that the ROMBO needed a special EPROM
programmer to program. Here is a link to a picture of the ROMBO. These
are no longer available.
If it's any help, the ROMBO programmer was an unmodified 'SmartZap'
running the standard firmware. There were 2 configuration modules
supplied, one was the normal 27C512 one (a suitably-jumpered 28 pin
header), the other was a differently-jumpered header with a flying
lead ending in a 3 pin socket that fitted onto the middle 3 pins of
the headed on the 27C010 module. For normal operation in the Portable
Plus, pins 1-2 and 4-5 of that header were fitted with shorting links.
I can send you reverse-engineered schematics of all parts if you need them.
-tony