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1

As others have mentioned, the Apple will drop to the monitor when it attempts to execute code that doesn't make sense (illegal/invalid instructions for example). As you have mentioned, it works fine when you boot the machine without the disk controller card inserted. This is good because it at least suggests the core system should be OK. The Apple II will ...


4

If your Apple is dropping you at the monitor, it means it tried to execute some set of instructions that went off the rails somehow. I'll admit I am fuzzy on all the details, but generally you can attribute that to either the Apple motherboard, or a peripheral, or code. The trick is to do a series of isolation steps to keep reducing complexity until you ...


5

What kind of error is this and how can I remedy it? To start with, this isn't an error, but the monitor program. Look here for a short command list - and Apple Monitors Peeled for in detail information. To leave it press CTRL-C - or RESET. It's an Apple II, so RESET will always help and bring the system into a default state while destroying as little as ...


3

FWIW, starting after the first FB (which appears to be the end of a previous instruction), this disassembles as: Lb8c9 lda $bb00,y lsr $bc00,x rol a lsr $bc00,x rol a sta ($3e),y iny cpy $26 ...


1

Are you talking about the Apple II port of AtariLab perhaps? I can't recall what they called it, but this is precisely how it worked. My info says it never made it out, but as is often the case in the late Atari days, I suspect some did.


3

You are not alone, as I have the same memory. Very "cube-looking" 9-inch monitors were a common peripheral for the Apple ][/][ Plus. You will find many pictures online of this setup, and may even be lucky enough to find the canonical Sanyo monitor (Model VM4209) for sale. (Smell the RAREity!)


8

Here's a Sanyo VM-4209 in a 1977 Apple II advertisement. It has a black handle on top (the VM-4509/DM 5109CX has a beige colored recessed handle): And another photo to show the color of the case better:


8

Sometime in 1980 (or maybe 1981) my school district purchased it's first batch of Apple II+ computers. The hardware our specific school district purchased consisted of Apple II+ computers, each with a single floppy disk drive and a small (maybe 8") black and white monitor. The only monitor Apple sold with the II series in 1980/81 was the Apple III Monitor. ...


23

The keyboard on the Apple II+ was designed to type uppercase letters only, which rather limited the machine's usefulness for word processing. Because almost nothing used paddle button 2 and very few controllers even had a third button, a common user-installed modification was to run a wire from the shift-key signal to the paddle-button-2 input. Word ...


11

I'm curious how these chips actually worked. Similarities [...] They are so similar, that Zip Technologies even won the case against Rocket-Chips manufacturer Bits & Pieces. Just, the manual doesn't tell a lot about the inner workings. Only that it's a "technological marvel" with the equivalent of "350 integrated logic chips" and "hundrets of tiny gold ...


3

No, for writes to the extended ROM space, the IIgs ROM 01 FPI memory controller does not assert /CROMSEL. I assume it’s the same for the newer CYA memory controller chip in ROM 03 systems but I have not tested. Here are the logic analyzer traces. First is a read from F0/0000, in which /CROMSEL is asserted as expected: Next is a write to the same address, ...


4

I might be wrong, but AFAIR it was something already present on the Apple IIc to support a 32 KiB ROM image instead of a 16 KiB (starting with ROM Version 0). For ROM access either half could be selected. So this isn't really A14, but the ROMs A14 to select one of two 16 KiB regions.


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