I went back home for Christmas, and my father had retrieved my boyhood Apple II+ from storage. We originally got it second-hand, and it came with some expansion cards and some mods installed, but I was a child, so whatever the computer did was what I assumed it was supposed to do. Now I'm older and a little nostalgic, I've spent some time reading up about the Apple II+ hardware, watched some videos about how things were supposed to work, and grown curious about how my Apple II+ had been configured.
Skipping ahead to the observations:
When I opened the lid, I found a coiled up wire that had a clip at one end, and was soldered to a 16-pin DIP socket. I assume this was the setup for the classic "one wire shift mod" that connects the Shift key to the joystick port, but like I said - it was loose and coiled up, neither end was attached to any part of the computer.
The joystick port did have something in it - two 16-pin DIP sockets piggybacked together, and just visible between them, a strand of wire presumably connecting one leg to another. I'm not sure which legs were connected, I tried to check with a multimeter but results were inconclusive. I don't know what this was for, but I figured I'd mention it in case it was relevant.
There did not appear to be anything attached to any of the pins between the keyboard and the attached circuit board (decoder board?), though I didn't take the case apart to look closely.
When I booted the machine up, the keyboard mostly worked. I typed a classic BASIC program:
10 ?"HELLO, WORLD!", 20 GOTO 10
...and ran it successfully. As you can see, number keys worked, letter keys worked, punctuation keys worked, shifted punctuation (?) and numbers (!) worked too. However, the symbols available from shifted letter keys (Shift-N → ^, Shift-P → @, Shift-M → ]) did not work.
The computer also had an 80 column card in it - I'm not sure what make or model, it doesn't have any identifying marks on it. When I switched to 80 column mode, lo and behold - I was typing in lower case, and BASIC wouldn't recognise any command I typed, unless I held down the Shift key to type in upper case. I distinctly remember typing school essays on this computer in AppleWorks (using PLUS-WORKS to get it working on the II+), and having upper and lower case work as expected, including printing the resulting documents and having the text come out as I expected, so however this system worked, it can't have been *too* hacky.
From what little I know about the Apple II+ architecture, my best guess is somebody installed a new and different keyboard decoder ROM that would send different codes for the shifted characters, so the 80 column card could distinguish them. However, both would need to be treated as "normal uppercase" by the regular video hardware and BASIC - were they flexible enough to handle that? Was this a common modification to the II+?
The weird part is that I'm pretty sure I discovered the secret "Shift-M" keystroke as a child, but as the machine is configured now, it seems to be impossible to type. Whatever modification has been made to this computer, is there likely to be an "off switch" of some kind, in case you really need to type "@" for some reason? If so, where is it likely to be found?
Sounds like you may have the Videx keyboard Enhancer II in your machine. That's the board underneath the keyboard. Does it have a connector on the back left side with some jumpers on it? Try holding down any key and see if it repeats. If so, that's a sure sign that you have it.
The Enhacer uses shift-Reset and Reset alone to switch between lower case and CAPS LOCK respectively. You can get the full manual for this board here.
Doesn't sound like there's a VIDEX enhancer. That was a pretty rare bird.
The VIDEX 80 column card was lower case capable out of the box as SCREWTAPE discovered.
The one-wire shift key mod was put there so that softwares that were aware of it (ASCII Express comes to mind) could display lowercase and uppercase properly, but only with the 80 column card activated.
As SCREWTAPE also discovered, typing APPLESOFT commands in lower case in 80 columns did not work, but lower case was displayed nevertheless.
There was another mod...the VIDEX lower case character generator, which replaced the regular Apple character generator.
With it installed you COULD display lowercase characters in 40 column mode, but you could not type in lower case (unless you had the one-wire mod and software that could understand it)
But whatever software needed lowercase would probably have been productivity software like AppleWriter (There was a VIDEX 80 col pre-boot disk for AppleWriter), AppleWorks (with a VIDEX 80 col patch) or VISICalc which used the 80 colun screen anyway.
Memory's a bit faded after all these years and I don't turn the ol' II+ on very much any more, but perhaps I ought to get it out a bit more. It does have the VIDEX lowercase character generator and the 80 column card installed. The last thing I used with it was ASCII Express, hence the reason why that example popped to mind.
Also...the one-wire shift key mod was connected to the game port, so that is why there is a double socket and a wire dangling from it.
Information on the one-wire shift key mod is here: https://macgui.com/blogs/?e=482
On some ][+ keyboards you could add a switch to the encoder board that would switch it into an upp/lower case mode. You also needed to swap out the CHARGEN ROM with a 2716 EPROM programmed with something like the "Dan Paymar" lower case image.
The wire from the socket was not connected to the encoder so this would not explain the shift key working.
But as softwarejanitor mentioned, there was a mod to the keyboard encoder that could enable the shift key (with caveats) - see Sather's "Understanding the Apple II," pages 7-36 to 7-38.
Guess we'll have to wait for the OP to chime in...
I went back to my parents' place recently, and this time I took the off the Apple II+'s base-plate so I could get a good look at the keyboard encoder. So far as I can tell, somebody soldered on the switch that enables the hidden "lowercase" mode, and consequently disables the ability to type ^, @, and ]. As far as I can tell, there's no custom character generator ROM - in regular 40 column mode, you always get capital letters no matter what. It's only when the 80 column card is enabled, that you get to see the lowercase characters (which was all I needed for writing school reports).
IMG_20240413_132203.jpg
Thanks for giving me the clues I needed to figure it out!
I installed a switch like that on my ][+ back in the day but I put mine on wires long enough to run outside so I could flip the switch without opening the top of the case. I also had a 2716 burned with a lower case character generator installed. Later I bought one of the clone keyboards that fit into a ][+ but was full upper/lower case with a caps lock key where the power light was. Then eventually I bought a used //e.