Replacing Apple II+ ROMs with 2716 EPROMS?

[TMA-1]

I am a retro fan, new to the Apple II, and may have shot myself in the foot with the first foray.

I picked up locally an Apple II+ that was disclosed to be missing its F8 ROM. The claim was, that with a borrowed F8 the system will boot, so I believed it to be sound in all other respects.

Prior to purchase, I got the distinct impression from this website, http://www.applelogic.org/APPLEASICs.html, that the 2716 EPROM was a suitable drop-in replacement for the original masked ROM.

I have a burner, the website has the ROM image, so I bought a 2716 and burned it, and bought the Apple II+ thinking I would have a functioning system. Well, since I'm posting for help, obviously not.

With the ROM slot empty, the symptoms were a good power-up, no beep, and a screen full of mostly question marks with some other occasionally blinking random characters.

With the prepared 2716 EPROM in place, those symptoms are exactly the same.

I can't seem to find any information suggesting a pinout translation is required in this situation, but neither have I located any corroborating evidence that it is NOT applicable.

Can someone tell me if I have a ROM issue still, or should I start checking all those pesky 4116's? Thanks in advance.

Ian

[david__schmidt]

 

I picked up locally an Apple II+ that was disclosed to be missing its F8 ROM. The claim was, that with a borrowed F8 the system will boot, so I believed it to be sound in all other respects.

With the ROM slot empty, the symptoms were a good power-up, no beep, and a screen full of mostly question marks with some other occasionally blinking random characters.

 

That's not necessarily the lack of ROM holding it back. It could be any of a number of other problems on the logic board. Without a known-good F8 to try with, you can't rule out other logic board problems. Troubleshooting them can be a gradute-level endeavor requiring an oscillisope and quite a bit of experience - though you can sometimes get lucky by swapping parts with another known-good board since so much is socketed. But then plenty of critical parts aren't.

 

Some notes for you to start with:

http://www.willegal.net/appleii/appleii-repair.htm

[Osgeld]

the 2716 isnt pin compatible with the original masked roms but you can make it compatible

 

http://www.willegal.net/appleii/appleii-integer.htm

[TMA-1]

Thanks guys! Those are both excellent links for the weapons locker.

 

Obviously I'll get to work on the ROM situation before trying to diagnose any other ailments that may or may not be present. I don't have quick access to a SMD inverter, so maybe I'll check my salvage inventory for a suitable conventional chip for an "outboard and ugly" interim hack. I'll let you know how I make out.

 

Thanks again.

Ian

[TMA-1]

Success!

My Apple II+ is now booting, and I can begin to explore this classic beast.

Neither I nor my local parts supplier had an NC7S04 SOT-23 SMD inverter gate as called for in the instructions at http://http://www.willegal.net/appleii/appleii-integer.htm, so I hacked up a similar solution. Perhaps someone else will find it useful.

Modified Instructions:

1. Take a 28-pin IC socket, and remove 4 pins from one end (2 each side) to make it a 24-pin socket with an extension. (The extension is probably not necessary, but a 28-pin socket is what I happened to have on hand.)
2. Take a 74LS04 inverter gate x6 chip, and break off all legs EXCEPT 7, 8, 9, and 14. (In my case I used the gate at pins 8 and 9, but if you broke those legs salvaging the chip from a previous purpose, you can certainly use any of the 6 inverters.)
3. Glue the back of the 74LS04 to the extended (pinless) end of the IC chip with epoxy or cyanoacrylate ("Krazy Glue"), so that the legs of the logic chip are accessible.
4. Bend up pin 21 on EPROM so it will not contact the socket.
5. Bend up pin 18 on EPROM so it will not contact the socket.
6. Put the 2716 EPROM in the socket.
7. Attach 74LS04 pin 9 to pin 18 of the socket by pushing a thin solid wire down the hole where the leg would go. Phone wire is ideal.
8. Attach 74LS04 pin 7 to pin 12 of the socket the same way, inserting the wire in addition to the leg already there.
9. Attach 74LS04 pin 8 to pin 18 of the EPROM.
10. Attach 74LS04 pin 14 to pin 24 of the socket.
11. Attach 74LS04 pin 14 to pin 21 of the EPROM.
12. (Note the last 2 steps can be one wire from socket pin 24 to EPROM pin 21 to 74LS04 pin 14.)

Edited September 7, 2014 by TMA-1

[Osgeld]

hey who cares if its stealthy it freaking works and you still did a good job doing it

 

grats on reviving a dead box, thats what I love

 

now if you have a drive you can use adtpro to transfer disk images to it, though since you dont seem to have a serial card you have to use the rather slow, but workable tape audio ports

 

otherwise you can use apple game server over the tape audio to least play with it

 

http://adtpro.sourceforge.net/

 

http://asciiexpress.net/gameserver/

 

PS look up "color killer" for an apple II, later machines had it, in a nutshell its a simple transistor mod that disconnects the color burst signal while in text mode giving a clearer text only screen on color monitors

 

its also nice to be able to toggle switch it when you want clear monochrome graphics, my IIc had it from the factory I still toggle switch it when I am in programs that are graphical, but still monochrome to get rid of the rainbow effect

Edited September 7, 2014 by Osgeld

[Ed in SoDak]

Great job Ian! I was rootin' for you. Only a one-day setback from picking it up, too. WTG!

 

Now, I wanna see a pic of that magic donor board that provided the 74LS04 and previously helped us both out with other chips.

-Ed

[TMA-1]

Thanks for the links and info Osgeld. I'll look that up. My "monitor" is my kid's castoff bedroom TV set, so I don't expect much out of it, and get pretty much what I expect.

 

LOL, what my good friend Ed is referring to is a board I picked up at a surplus store for $0.50 a very long time ago, that is a great source of 74LS series logic chips. Any time I need a gate or two, that board seems to have it.

 

I was joking with Ed that I wonder what the board did in it's first life. It looks like an 8-bit PC board, but the only other interface is a 2 x 15 socket. The big chip is an interval timer of some sort. And there's a mess of logic. Whatever it did was complicated. Here's a picture. Please don't tell me I've been scrap-harvesting a controller for the Hubble Space Telescope!

[Arbee]

Congrats on getting it going! I have no idea what that ISA board is but you aren't kidding about it having about 1 of every 74xx chip on it.

[datajerk]

though since you dont seem to have a serial card you have to use the rather slow, but workable tape audio ports

 

It's still possible to get disks copied via the audio ports in a reasonable amount of time. http://asciiexpress.net/diskserver

 

The code (c2t) is open source, so making your audio images is easy too. Average time to create a 140K floppy via c2t 8000 bps + compressed audio is about 2 minutes. Add 30 seconds if you need to format the disk first.

Edited September 7, 2014 by datajerk

[Ed in SoDak]

LOL, what my good friend Ed is referring to is a board I picked up at a surplus store for $0.50 a very long time ago, that is a great source of 74LS series logic chips. Any time I need a gate or two, that board seems to have it.

 

Please don't tell me I've been scrap-harvesting a controller for the Hubble Space Telescope!

 

 

Wow, what a board! Your per chip cost so far is 8.33c each for the six you've harvested. Some people might flame the backside with a propane torch and harvest the lot with a bang against a tub to catch the dropping chips.

 

Just in case some day you do learn it's some kinda rarity, mark the 74LS number of the chips you've removed, since there have been only six so far.

 

-Ed

[R.Cade]

BTW, the Apple II won't work with a language card (16k expansion) with EPROMs. The way it handles the ROMs on the motherboard is not compatible with EPROMs even with your mod...

 

Also, I seem to remember that the F8 ROM is handled by the language card, so it isn't needed once you get one? I think for this reason, the plus may never have had one...

Edited September 7, 2014 by R.Cade

[Ed in SoDak]

Now that Ian has his newly-acquired IIe going, I planned to help get him some basic software on floppies for it. I have a IIc and most if not all the "factory" disks. I planned to either make copies or send him a couple of the backups I have that came with my machine. Only problem is the IIc is 128k and he has only 48k on his IIe. One of my flioppies is marked ProDOS for 64k, the rest say 128k IIc.

 

Would these even work on his unit?

 

I have an Apple Legacy CD that included some Apple II software as DiskImageMounter/Disk Copy img files. I can't seem to open these, while all the other Mac-specific img files work fine. My alternate hope was to use adtPro to makes floppies of these, but if I can't open them on the Mac itself, not sure how I can extract the files to put on a floppy.

 

So I seem kinda stuck at this point trying to help him out. I don't want to waste effort, as my IIc is currently boxed up and I've never run adtPro to make sure my cable would work, etc.

 

Any suggestions for other ways I could provide what I might have? Or should he just go for the audio port as the easiest way at this point?

 

-Ed

[The Usotsuki]

All the //c stuff unfortunately needs at least 64K, because ProDOS needs 64K...

[TMA-1]

Actually it's an Apple II+.

 

The link datajerk provided, http://asciiexpress.net/diskserver, seems to have everything I might need to bootstrap a software-less system with one disk drive and the cassette port. And I've figured out that the buffering over the internet was spoiling my loads. Now that I download the files and play them locally, my loads work.

 

New hurdle. My disk drive may not be working. The Dos 3.3 "with formatting" process fails immediately as soon as the disk drive is accessed to format the disk. "DISK ERROR".

 

I am using a new DSDD that has been bulk erased to remove any interference from "PC" tracks. And I've cleaned the disk head. The drive was already very clean inside and out, but who knows? Is there something obvious I'm missing?

 

Ian

 

[edit] I took the cover back off so I can see what's going on. When the machine powers on, the disk spins. (But of course it is blank.) When Insta-Disk goes to format it, it does NOT spin. Why not?

Edited September 8, 2014 by TMA-1

[Ed in SoDak]

My bad on the model, don't know where I upgraded your II+ to an e.

 

I recall have other disks with mine that have DOS 3.2 or 3.3 on it other than the factory disks. Would those be more likely to work on the 48k II+?

 

-Ed

[TMA-1]

Okay, I figured out that the controller had to be in Slot 6. That made a difference. Now when Insta-Disk paints its graph and goes to format the disk, the light goes on and the disk spins. The head does not move. The "FORMATTING DISK" is then quickly replaced by "DISK ERROR".

 

I'm thinking the disk drive is a dud. Opinions?

Edited September 8, 2014 by TMA-1

[david__schmidt]

Okay, I figured out that the controller had to be in Slot 6. That made a difference. Now when Insta-Disk paints its graph and goes to format the disk, the light goes on and the disk spins. The head does not move. The "FORMATTING DISK" is then quickly replaced by "DISK ERROR".

 

I'm thinking the disk drive is a dud. Opinions?

 

Slot 6 is ubiquitous and generally expected for the Disk II on the Apple II. Some software is hardcoded to look for it there, so it's safest to just locate it there and be done with it.

 

So the disk error can be any of a number of things. It can be a faulty write-protect switch, or maybe even bad media. The drive hardware itself was/is pretty robust, so I'd be disinclined to suspect the drive first.

 

You could try ADTPro and have it send EsDOS II over audio - that could at least get you another data point by loading the OS and then trying to have it format (INIT) a disk.

[TMA-1]

You could try ADTPro and have it send EsDOS II over audio - that could at least get you another data point by loading the OS and then trying to have it format (INIT) a disk.

 

Ah, okay,... I had misread the initial requirements page, and had thought that having only 48K and no serial card either, I was pooched for using ADTPro altogether. My bad.

 

So,... did that,... and when I go to INIT my disks get "DISK ERROR: I/O".

 

I have tried with 2 different floppies. The head seeks the outside track position, but does not move thereafter, and the error results. The drive is not a standard Apple drive; it is a 1/2 height "Shamrock" animal. It looks very clean and pristine inside, with no obvious loose connections or other gimmes like exploded caps. The write-protect switch was a good idea; took it apart and tried jumping the connection to close the circuit. Also tried re-seated all the chips on the floppy controller. Nothing has any effect. I'm running out of ideas. Maybe it's called "Shamrock" because you're lucky if it works,...

[The Usotsuki]

DOS 3.3 only needs 48K (there's ways to run it in as little as 16 but you can't do anything then, a lot of stuff does assume the 48K configuration).

[Ed in SoDak]

Thanks! That's good info.

 

I have the System Utilities disk which includes an option to convert a ProDOS disk to DOS 3.3, maybe I'll try that to make a copy.

 

Mail to Canada is slow and expensive, I was trying to avoid shotgunning Ian a bunch of floppies that may do nothing on his system but waste postage and our time.

 

Maybe there's a Candian AA member reading this who might have a extra II+ DOS floppy laying around they could mail to Ian for a "known good" disk he could test with?

 

-Ed

Edited September 8, 2014 by Ed in SoDak

[TMA-1]

Epilogue,...

 

It was indeed my Shamrock 1/2 height floppy disk drive that was the latest trouble. I solved the problem with the shotgun approach--I bought another Apple II+ bundle that was too good to pass up. It is a working system (so I have 2 now, including my ROM-repaired one), with 2 disk drives and a serial card as a little bonus. It cost even less that the system missing the ROM.

 

The site at http://asciiexpress.net/diskserver/ is a godsend; thank-you datajerk for creating it and chiming in to point me there. It's amazing how these machines seem to get separated from their libraries of software over the years for whatever reason. Thanks Osgeld, for the critical information that got me going, and everyone else who chimed in with information and support. Thanks Ed for being my cheering section on this endeavor. I'm gald you got your Timex-Sinclair 1500 going, back from the dead like this Apple.

 

Someday when technology is taken out by EMP, 8-bit computers will rise to take over the world,...

 

(Okay, what was in that brownie?)

Ian

 

[MarkO]

Epilogue,...

 

<< BIG SNIP >>

 

(Okay, what was in that brownie?)

Ian

 

We're not telling......

 

MarkO

Edited September 9, 2014 by MarkO