On 05/12/2014 08:34 PM, Mr Ian Primus wrote: Excellent, thanks. So, given that, does anyone know: 1) If the Plus chassis harness connector (PSU and video) matches the 512K? I've not been able to find pinout information online. 2) If the Plus keyboard/rodent will work? (I assume the mouse is the same, but I'm not sure if all Pluses had the keypad - and possibly send different codes - or not) I don't actually *have* a keyboard for my Plus right now, but I have one lined up to collect when I'm next in England - in the meantime though I could at least see if the board powers up and shows signs of life. cheers Jules

On May 12, 2014, at 11:29 PM, Mr Ian Primus <ian_primus at yahoo.com> wrote: I have done exactly that, though with a somewhat newer Mac. And it was Mountain Dew. Slow, but there wasn't much that I found myself truly unable to do... at least the keyboard washed out and dried acceptably within a few days. - Dave

On 13 May 2014 22:57, Fred Cisin <cisin at xenosoft.com> wrote: What about a killer poke? http://en.wikipedia.org/wiki/Killer_poke -- Yoyodyne Propulsion Systems: "The Future Begins Tomorrow" Visit us at: http://www.yoyodyne-propulsion.net -------- "Hanging on in quiet desperation is the English way "

"I always lied a little to overcome their fear of trying." And you apparently tried a little, to overcome your fear of lying, as well. ;-) On Tue, May 13, 2014 at 5:49 PM, Fred Cisin <cisin at xenosoft.com> wrote:

Oops.. should have mentioned this for clarity: The original 128K Mac definitely can boot from the external hard disk. But without a later 512K / 512Ke ROM you must first load MacOS from floppy, and have the proper extension on your OS disk. The extension allows the user to manually re-boot from the hard disk on-demand. The same extension can also be configured to run at start-up, such that it transparently transfers control to the external disk automatically, once the disk-based MacOS has loaded the extension. On Tue, May 13, 2014 at 5:55 PM, drlegendre . <drlegendre at gmail.com> wrote:

On May 13, 2014, at 18:55, "drlegendre ." <drlegendre at gmail.com> wrote: Well, upgrading a 128k board to 512k is a relatively simple operation, since they were the same actual board with a different BOM. Getting beyond that is another question; I'm interesting in finding out what was done to the 128k that I grew up with (and still have) that has 1MB and definitely did boot from an HD20 for much of its life, but wouldn't run some games (notably, Prince of Persia) which needed a Plus. - Dave

On May 13, 2014, at 20:02, "drlegendre ." <drlegendre at gmail.com> wrote: It's definitely not a Plus logic board; no SCSI, for one thing. I have an uncle who worked for Apple around the time, and I think he was the major source of upgrades. In any case, I'll be able to speculate further once I get a chance to open the box; I have the tools, but the machine itself is still at my parents' house in a different state. One of these days I'll bring it back here, but I did at least make sure to remove the battery last time I looked at it. Indeed, but it was the same board, with the changeable areas silkscreened appropriately. Yes, you need to swap out the 4164s for 41256s, add in an 'AS257 (if memory serves) and jumper some wires, but it was doable. 1MB required some reengineering, though. I'm curious to see what was done, since I doubt my uncle would have added a third-party expander (too much pride in workmanship). - Dave

On Tue, May 13, 2014 at 8:02 PM, drlegendre . <drlegendre at gmail.com> wrote: That was done to some 128K machines, but you need a new back because the Plus board is different (the DB25 SCSI, for one). It's also possible there's a DoveSnap or something similar inside. I installed a couple on my mother's machines for her small office - took a 512Ke to a Plus, essentially (1MB of RAM total and SCSI with the DB25 on a replacement battery cover). Yes. The only socketed parts were the ROMs (which makes it a pain to use a Fluke 9010A with an old Mac - you have to desolder the CPU and install a socket first - I was wishing for a socketed CPU last year). People did desolder the RAMs in 128K boards to varying degrees of success. There are 2 or 3 variants of the 128K board - the later ones are trivial to re-strap, but I think the earliest needs a dead-bug component added. Instructions for said procedure are floating around the net. I ran across them last year when I was diagnosing a problem with a dead bare 128K board I got from a list member. As with any multi-layer chip replacement, it's easier to do if you clip the legs at the body (and used 4164s weren't worth enough in 1985 or 1986 to make intact extraction a priority over an intact boad) and remove the pins one by one. It's still tough to heat the power and ground holes to suck them clean, but as long as you don't delaminate them, it's possible (and delamination just means more work). Another technique was to clip the 4164s out at the shoulder then solder the 41256s to the bare legs. Far easier than extracting 32 tough pins as long as you have dexterity and a fine point on your iron. -ethan

There is an OUT on MSX computers that reverse the keyboard port from input to output. Press a key, burns the 8255 :)