Reading back over this thread, the fact that the HMM recommends system board replacement for RAM errors ties in with Goldeneagle's recollection of RAM soldered to the motherboard.
I was photographing my ThinkPad 300 today ahead of putting it up for sale, and thought more pictures might make a good addition to this thread.
Here it is beside a 700C, showing the clear differences in case colour, style, and detail. Note how some of the 700 design details are carried over, such as the rolled edge at the front of the keyboard, screen sliders and lid latches, etc. Really this is just dressing up a generic laptop to look like an IBM design. Bear in mind that these common design details were also inherited by the 700C from the prior PS/2 Note and PS/Note models, such as the N33, N51, 425SL, and in this respect the Zenith-made 300 is as much a tribute to the PS/2 Note designs as it was to the then brand new ThinkPad 700. The keyboard is completely different to the PS/Note or 700 layouts, and it has a different typing feel.
From memory, the only other IBM notebook that I've encountered in this slate grey colour was the PS/1 Note 2141-182. It's nothing like the cream of the German 700/720, nor the grey of the German 750. It's also not a flat uniform colour, but more like what would be termed 'grey marl' for a T shirt:
General views:
Panel at the top right of the keyboard covers the 387 co-pro socket and RAM sockets:
VGA, port replicator connector, PS/2 mouse, parallel, serial, power ports on rear:
I never did see a port replicator for one of these, and Google brings up nothing now, but I did manage to find an image of a Zenith 325L with what looks like a port replicator fitted... a 2" deep slice that presumably replicates at least parallel, serial, vga, power, and mouse ports for quick desktop docking:
Battery latch and slide-out battery on left side, plus lid latch:
Nothing on the front, battery and PC speaker (beep) visible on underside:
Lid latch, 1.44MB Floppy drive, panel covering modem module socket with removable blank for modem connector (modem not present), uncovered LAN port (as goldeneagle referred to above, connecting with an Apple AUI LAN Adapter):
ID sticker on the underside is very non-standard, but in classic IBM straightforwardness it is "Manufactured
for IBM" not "Manufactured
by IBM"; "Shimane, Japan" would have been Zenith's manufacturing plant:
Fujitsu owns
a large PC manufacturing plant in Shimane that opened in October 1990, initially for manufacturing desktop PCs but more latterly manufacturing just PC laptops, according to that 2008 press release. I wonder if this was the plant that made the 300?
The type-model-serial number sticker at the bottom is pre-printed up to to the 55 of the serial number, with the real serial number 24681 overprinted in a slightly different font. 55- indicates Greenock, UK as plant of manufacture. This is a UK model, so would probably have been processed through Greenock even though originating from Zenith.... probably checked then boxed up with destination country appropriate manuals, power cord & power supply, etc. This happened on "made for IBM" products, such as the
PS/2 wedge mouse made by Logitech but branded with a 23- serial number suggesting it was manufactured in Raleigh, USA.
With the Zenith power supply mentioned above:
Enjoy!
