Extra wire going from keyboard to main board

That's the shift-key mod to enable some programs to read the shift keys on the keyboard. This will allow you to enter upper and  lower case characters.

jeffmazur wrote:

That's the shift-key mod to enable some programs to read the shift keys on the keyboard. This will allow you to enter upper and  lower case characters.

This is correct.  There are a number of ways to implement it.  This is one of the cleaner versions I've seen.

The Apple II and II+ (which are the same hardware) do not support lower-case letters. Since this is a big drawback, especially for word processing, modifications to add lower-case were the most common hacks on these computers.

The mod involves a wire from the shift key to a button input on the game port, and also a changed character generator ROM with lower-case glyphs.

The Apple III and Apple IIe were designed to support lower-case, to make them suitable as business machines without being modded.

ebruchez wrote:

How can I identify if I also have the ROM with lowercase? This ROM is Apple-branded, from 1981.

tl;dr answer:

That ROM does not support lowercase

Longer explanation:

The part number 341-0036 is Apple's internally assigned identifier for the Signetics 2513 character ROM.  It supports only 64 characters, which includes uppercase letters, numerals, and punctuation.  Those were used from the first generation of motherboards through Rev 4, inclusive.  (Another way to recognize such motherboards in the presence of MEMORY SELECT blocks in row D, row E, and row F.)

[EDIT]

Oopsie!  I confess there are some compelling doubts about my identification above, based on the following clues:

• your photo of the underside of the motherboard shows a 20-pin IC beside 6502, which suggests that it's an RFI motherboard.  (much later than Rev 4)
• your photo of the underside of the keyboard encoder shows a later model which had provisions for a lowercase switch and a socket for numeric keypad.
• an online search for "341-0036" returned hits for multiple incompatible keyboard generators, including the original 2513, the later 256-chaaracter 2316, and the Katakana keyboard generator in the J-Plus.

Did Apple use the same part number "341-0036" for all their keyboard generators before the //e??

ebruchez wrote:

Thank you! So it seems that unless I get another ROM, the shift mod has little to no utility at this point.

Not quite, there's a little more confusion.  The shift-key mod just enabled software to detect when the user pressed the SHIFT key -- it didn't enable the computer to display lowercase.

Most users didn't upgrade their motherboards to display lowercase.  Some users installed video cards that could show lowercase, like Videx VideoTerm or ALS SmartTerm.  Or they ran programs that simulated lowercase by using display attributes or using graphics modes.  Examples: Apple Writer (text attributes), Magic Window (graphics mode), Bank Street Writer (graphics mode), EDASM (text attributes)

So your average Apple II or Apple II Plus couldn't natively display lowercase.  Programs like Apple Writer and Bank Street Writer allowed you to type lowercase characters into your documents, and print those lowercase characters in printouts.  The shift-key mod enabled programs to detect when you were holding the shift key, and the program would use that to decide whether to convert your typing into uppercase vs lowercase.

The shift-key-mod was just a hack, but it was a successful hack so it was generally accepted.  It was so common that Apple included a shift-key-mod option on the Apple //e motherboard for the sake of software compatibility.

ebruchez wrote:

Here is the marking with the board revision:

The part number 820-0044-C is definitely an RFI motherboard.

Although the factory-installed character generator doesn't support lowercase, that version of the motherboard could be upgraded to display lowercase by swapping a different character generator into the "ROM SPCL" socket.

James Sather lists the various motherboard revisions in Appendix G of Understanding the Apple II.  He gives a much better explanation of the shift-key-mod starting on page 7-36 so I suggest you read his explanation...and maybe disregard the arcane stuff I previously wrote.

That chip doesn't contain lower-case glyphs, so you don't have a complete mod in that system. There may have been some word processors that used the shift key to display inverse characters, that would then print as uppercase; but such a setup would be hard to use.

robespierre wrote:

That chip doesn't contain lower-case glyphs, so you don't have a complete mod in that system. There may have been some word processors that used the shift key to display inverse characters, that would then print as uppercase; but such a setup would be hard to use.

It's a simple enough exercise to install a lower case character generator chip in that socket.

The Videx Lower Case chip was a populer substitution to allow the display of lower case characters on the 40 column screen.

The manual for it is here: https://mirrors.apple2.org.za/ftp.apple.asimov.net/documentation/hardware/video/videx_lower_case_chip.pdf

and the chip .bin file is here: https://mirrors.apple2.org.za/Apple%20II%20Documentation%20Project/Chips/Videx%20Lower%20Case%20Chip/ROM%20Images/

You can burn it onto a 2716 EPROM and it will work in the RFI motherboard.