Hello
anyone have an extra E8. 341-0014-E8 Apple II ROM that they'd be willing to sell me?
looking for an original.
thanks
michael
Anonymous
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By "original" do you mean an original physical specimen vs original functionality?
ReactiveMicro sells a SOIC adapter that's functionally equivalent to "Applesoft BASIC E800 - PN: 341-0014" for $35, but it isn't physically identical to the original. (It's a surface-mount IC soldered to a DIP adapter.) https://www.reactivemicro.com/product/9316a-to-2716-soic-eeprom-adapter/
So, depending on your exact need:
I would offer to trade mine if I had one, but the previous owner of my Apple II Plus had (amazingly!) revised the motherboard to accept 2732 EPROMs with twice as much capacity as the originals...but I don't have the original parts.
Mobo ROMs.jpg
I'm pretty sure he means an original Apple labeled chip. Which makes sense if he is trying to restore a ][+. However realistically the only source for these in today's world is parted out of another ][+ motherboard. So it's unlikely unless someone has a board that is badly broken that they'd be willing to part with a chip like that since it makes their board non-functional.
Any ROMX owners out there? They could remove all of their existing ROMs and part them out. Probably make more money than the cost of the ROMX!
I would imagine few would be willing to part with their original ROMs. I sure wouldn't. ROMX is great for what it is... but I'd still keep my original ROMs.
Does your hacked board with EPROMs work with the Language card? I understood they would not, at least without some extra circuitry.
Are you asking about the ROMX? If so, yes it will work with the LC and all other 16K RAM cards. The original Apple LC has its own F8 ROM and that does need to be disabled. But this is a simple mod that does not require any extra parts. See the ROMX Installation Guide.
Why would that affect operation of an Apple Language Card or any other 16k RAM Card like the Microsoft one or the myriad of clones? Doesn't make any sense to me why it would matter.
My guess is that he was referring to the original Apple II Language Cards which had their own F8 ROM, not the myriad of 16k RAM cards *without* the F8 ROM.
The original Apple Language Card looks like this:
APPLELC.jpg
Regards,
Mike
No, normally if you try to replace the Apple ROMs with EPROMs, the language card can't disable them when it's RAM takes over instead, so you get bus conflicts and it crashes.
https://classic-computers.org.nz/blog/2010-03-06-problems-with-replacement-appleII-eproms.htm
That doesn't happen with properly made adapter sockets, because I've run 2716s in ][+ motherboards before. The simple ones that article talks about indeed do not work. I'd have to do some googling or find the one I used back in the day with "The Freeze"'s F8 ROM for cracking copy protection. I don't know how the motherboard mods are done exactly either, I've seen a mod that required adding a 74LS02 in an empty spot on a ][+ board for that years ago. I would assume the motherboard mods could be done right or wrong as well. If done wrong that would certainly result in what you are talking about. But I know there is a workable solution because people have done it for years with ][+ units with a 16k RAM card in them.
Yes, when using EPROMs in a standard Apple II motherboard, you need to invert the INH signal coming from the expansion slots. This can be done by adding an inverter chip to each adapter socket or by adding a single chip to the motherboard (which is what most Apple clones do). The ROMX board also takes this into consideration with its logic design.
That's not what "normally" happens. That's just an illustration of one particular mod, which probably just disconnected pin 18 -- an easy shortcut that sacrificed the function of pin 18 (INHIBIT) to allow EPROMs in that socket to be enabled exclusively via the chip-select signals at pins 20 and 21 (which are both wired together).
If you are modifying a computer, you have the freedom to sacrifice functionality...or to implement or preserve whatever functionality you want. In the story at that webpage someone just chose to sacrifice functionality for simplicity, whereas the next owner didn't accept that particular sacrifice.
Right you are!
See James Sather's book Understanding The Apple II for an example of EPROM adapters that retain the INHIBIT function (pin 18) by re-routing it to a different chip-select input on the EPROM.
The original 2516 ROMs had three chip-select pins, but Apple's motherboard needed only two...so they conntected pins 20 and 21 together. In the process of adapting my motherboard to accept EPROMs, it took only a little more effort to disconnect the duplicate chip-select from pin 21 and route it to AN2 instead. That enabled the motherboard to accept 2732 EPROMs, twice as much ROM, with AN2 now switching between two ROM banks.
Slightly off-topic...but related...
For what it's worth, the Apple Firmware Card can be easily adapted from 2K ROMs to 4K EPROMs by disconnecting the pulldown resistor R2 and connecting pin 21 of the EPROM sockets to a spare D Flip-Flop in the 7474 chip at B2. With these mods, the ROM card has an additional soft-switch to enable the second bank:
$C080 - enable ROM, first bank(original switch)$C081 - disable ROM(original switch)$C082 - enable ROM, second bank(new switch)ROM CARD mods front.png
ROM CARD mods back.jpg
Consequently, if you're going to modify anApple motherboard or firmware card to accept EPROMs, I highly recommend taking it one step further and upgrading from 2K ROMs to 4K EPROMs. It's not much more effort than adapting it for 2K EPROMs, but 4K EPROMs give you twice as much space to work with.
Here's a good-faith attempt to steer my last comment back onto the original topic:
To those users who want to tinker with custom EPROMs, the mod above will enable you to install twice as much ROM so you can implement cool features. In my computer I implemented memory-snapshots (save/restore the state of the whole computer), Mockingboard sound (including a CTRL+G chime), built-in Watson, startup animations and menus. By doubling the ROM capacity, I added new features without sacrificing any old ones!
Tinkerers who trade-up to EPROM can donate their OEM chips to preservationists like the OP who want original chips. (I would cheerfully contribute mine if I had them.)
Hmmm.... 2732s in a ROM card... I could put both INTBASIC and Applesoft ROMs in one and put that in a clone like my Franklins, Micro II or my PineApple which won't run some software (like many versions of ProDOS) due to the factory EPROMs not being exact (mainly they don't have "APPLE" in the right place or they don't pass checksums some copy protection looks at.
I wonder how hard it would be to put 27c32 into the clone ROM card I'm building? Probably the same parts, the layout's just a little different and it has jumpers instead of solder pads for the ROM/EPROM change.
20220805_213759.jpg
Unfortunately, the adapter described by Sather has EXACTLY the problem described by rittwage when used on the Apple motherboard! With most 2716's, Sather's adapter will work to correct two of the chip selects. But the third one used by Apple's 2316 ROM's is an active high signal (CS2, pin 18). This means that to fully emulate the ROM with an EPROM, you also need to invert the INH signal coming from the expansion slots. Otherwise, cards like the original Apple Lanuage Card cannot disable the motherboard ROM when it tries to drive the bus.
Your mod to tie pin 21 to the AN2 will allow bank selection with a 2732. But it will still suffer from the lack INH support and thus would not work with a LC.