Found this little guy at the thrift store about a month ago. I've been using it extensively, and wanted to review both it, and the switches.
What is it:What we're looking at is a Sharp Intelliwriter PA-1000H thermal writing machine.
A thermal writer is a machine that falls into the "electronic typewriter" category, though that's a bit of a misnomer. It's really more of a printer, word processor combo as the key presses are sending scan codes to a computer, which is sending commands to a printer. In form, thermal writers are very similar to the more common daisywheel writers.
The difference is the thermal print head: it allows for very quiet, energy efficient printing in a small battery operated form factor, at the expense of needing to use thermal paper or thermal transfer ribbons, and not being capable of producing carbon copies.
These machines were first marketed in the early 80s, and clung on into the early 2000s. Early on they were marketed as being an "on the go" typewriter solution, but as they lost market share to personal computers, they became more and more about being the cost cut option. The later you go, the cheaper these tend to be made. Overall, they're an interesting evolutionary dead-end for typewriter like machines, representing some of the last innovative ideas in the field before the word processor truly took over.
This device:The PA1000H is an earlier thermal writer. These seem to have been marketed between late 1983 and early 1985, which is towards the beginning of the thermal typewriter run.
As such, this machine is fairly well built. It's made of chunky, durable plastic and has a nice multi-toned appearance of grey, cream and silver with black and clear trim adornments and a dark drey over case.
Being an earlier machine, it is a bit technologically limited. While later machines allowed for different fonts and justifications, this machine has only two fonts: the default, which is a chunky text, and a "battery saving" text with thinner letters. All print in 10cpi justified "pica" font. Thankfully, it does have a slew of other features: auto centering, right justification, tab sets, numerical tab sets, automatic indentation for bullet pointed lists, bold (really double width) text, underlining, and word by word underlining.
One of the defining features, compared to its competitors, is the 80 character screen, which allows a full line of text to be displayed. Many of these machines had less than 40 character displays, which were quite difficult to use. The 80 character display, broken up into 2 40 character segments, is at least minimally viable. It's functional in most of the typewriter's modes.
Speaking of modes, this machine employs four: typewriter mode (the text prints as you hit the key), line mode (the text prints as you finish the typed line, allowing for error handling), Memory I mode (write a document) and Memory II mode. Memory II mode is the most complicated: it allows you to create up to 26 short documents, one for each letter of the alphabet. These are functionally meant to be page headers and small repeatable things. These can be recalled with a button in any of the other modes and inserted on to the page.
Out of the box, the machine has a paltry 2k available to the user for these documents (it's really 4k, but the program takes up about 2k), which equates to about 2200 characters. This was expandable to 6k (8k total) via a RAM expansion slot (all memory is battery powered RAM) which has a proprietary part number in the manual. Through trial and error I found that the generic part number is HM6264LP-70, which thankfully is cheap and readily available. If you're going to use one of these for anything meaningful, get that expansion RAM.
In addition, the machine has an RS232C serial interface port. Unfortunately, it appears from the pinout that this expansion slot would've housed the interface control, so using that interface is not plug and play. One would need to figure out which controller Sharp used in their interface part, then engineer a solution around it.
FWIW, the machine is Zilog Z80 based in its architecture, but the pinout doesn't suggest they used the bolt-on Z84 serial interface. Maybe this predates it? I didn't get that far.
Print quality is pretty good for machines of this class, nice and dark, and fully ledgible. Text is a tiny bit blocky but fully readable.
The top case is quite functional. It holds your manual, some extra paper, and two thermal transfer ribbons (if you have them.) It hinges at the back and clips in on the front, and makes for a clean travelling package along with the carrying handle integrated into the body of the typewriter.
In addition to the documented features, this machine has an undocumented demo mode (hold down margin release + 1 + 2) and a diagnostic mode (hold down code + z + c).
Takes 4 D-cell batteries, which seem to last it a good long time. I put one set in and haven't killed them yet. It does allow the use of a wall wart power supply, which should be 6 volts center NEGATIVE. This is weird by today's standards but was fairly common in the 80s, so watch out for that.
What else can I prattle on about that isn't the keyboard?
...
Geekhack is all about the typewriter, right?
No?
...
Okay. Fine.
The keyboard:Obviously the biggest standout here is the keyboard, which uses acclaimed Alps SKCL green switches.
As everyone who clicked on this knows, Alps linear greens are the earliest of the complicated Alps switches. Most keyboards that used them were produced by Zenith, but this thermal writer also has them. From my research, it's unclear if later Sharp machines continued to use Alps switches.
Alps linear greens are well documented in this community, but after using them for a month, my opinion is very positive. They have a nice, un-scratchy linear travel, with a small tactile event about 2/3rds of the way down. When in good condition (as these switches were) they're fairly smooth and light, not scratchy at all (though not 100% smooth, as you can definitely feel some contact resistance as you press the switch) with a shorter than average travel.
That tiny, phantom tactile event is what really sets these switches apart for me, and makes them among the best "linears" I've ever used. They're something kind of between linears and tactiles. The tiny bump almost unconsciously cushions your finger's fall towards the bottoming out event, which somehow makes them very pleasant to use. The slight resistance from the plates also isn't unpleasant, giving them a sensation I would almost equate to the ASMR of gently scratching off a lottery ticket with a pocket knife.
I really can't describe what exactly it is that makes all of this come together in such a pleasing way, but trust me when I say that it does. These stand out as being lovely to use. I was lukewarm on linears before these, but this has made me reassess some opinions (though they'll never be a Model F.)
On the construction itself, this keyboard, like most Alps boards, has a metal backplate over circuit board design. It's sounds very robust and pingy, with a thick plasticky bottom-out noise.
Also notable are the keycaps: multi colored, double shot Alps mount PBT caps in a handsome grey/blue/green motif. They really do suit the machine quite well.
As far as the layout goes: it's functional for the machine it's attached to, but obviously not perfect. These days were still the wild west for keyboard layouts, especially in the typewriter space. Allot of functions are hidden behind modifiers, and you really need the instruction manual to figure it all out. Still, it does have an ISO enter key, the single/double quote button is where it ought to be, and the shift keys are about correct. Backspace is of the small variety, but this is more forgivable on a typewriter, where you were intended to type it right the first time.
Moddability:I have very mixed feelings on modifying the PA-1000H to be a computer keyboard, especially if it's done destructively.
On one hand, I mist admit that it's really not a bad candidate as far as these things go. They keys and caps are high quality, the switches tend to be in good condition because of the machine's integrated cover, and with some clever maneuvering it can be made into a modified 65%. If you fond one in otherwise trashed condition, I say definitely go for it.
If you must mutilate one in workable condition, at least be nice and post up the remaining parts for reasonable amounts on ebay. I'd surely love a paper bale without any broken tabs...
To make a point against modding, I kind of like it for what it is: a power sipping portable thermal writing machine with a high quality keyboard. I enjoy writing, and this thing is a pleasure to use for journaling and drafting out thoughts. It's dated, sure, but it really is a well thought out, beautiful machine which stands out in its class and must be appreciated for that.
I personally wouldn't modify mine by chopping it up, but would be open to non-destructively finding a way to stuff a converter into the body, in case I wanted to use it as a keyboard sometimes. It's just about small enough to get away with being on a desk as-is. This is largely the reason why I started digging into its architecture, and was saddened that it didn't have an inbound serial controller: that would mean a potential to use it as a keyboard AND printer peripheral, which would've honestly been pretty baller.
As it stands, I'm leaving it alone, but may non-destructively mod it in the future.
