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Hi all,
I'm trying to prepare an Apple // europlus for a small local no-profit museum so visitors can use it.
I am familiar with Apple //e and I am a bit lost here.
I understand the original Apple 2 did not auto-start so you had to type PR#6 to boot from floppy. However, ROM F8 is 341-0020-00 which I understand it should be the auto-boot one.
The other ROMS are
341-0015-00
341-0014-E8
341-0013
341-0012-00
(D0 is unreadable from the pic I have)
If I power up with a floppy controller in slot 6 and drive connected (which I don't know if it works) I have "Apple ][" displayed. If I hit "RESET" it takes me to Monitor. I tried CTRL-C, CTRL-B, CTRL-P and 6 and nothing works. The only key which works is RESET.
Without the floppy controller, the Apple beeps twice and drops me to monitor straight away.
I see that 1 RAM chip at row E is missing and I understand that one might connect a language card there with a memory expansion. But I don't have a language card with this system.
What I have is pictured below, plus the controller card. I haven't tested the board with the VS1000 on it as it has tantalum on the 12V line and I'd rather replace them before I use it.
I've re-seated and contact-cleaned all the RAM and ROM but nothing changes.
I don't know whether I am doing something wrong or maybe there is something wrong with the system.
Someone recommended I checked the ROM are still correct but I understand they cannot be read directly with my TL866II? A link online suggests I can just use an inverter to make them (2316B) compatible with something the TL866II can read (2716).
https://www.dmcmillan.co.uk/blog/testing-apple-ii-europlus-roms
Can someone help me? And is an inverter and some re-wiring really required to just read those ROMs with the TL866II? It feels weird.
Also, what would be the best way to replace those ROMs if needed? Is there a modern rewritable IC available? Does it have to be something which requires 21V programming?
Thanks for your help!
Tony
You need that one RAM chip. The machine will not work without it. When you put a language card, this chip is simply moved to the language card and you connect the ribbon cable in its socket.
If you don't have a RAM chip to put in the empty socket, you can still test the machine, but you have to remove the entire row. Then the computer will have only 32K of RAM instead of 48K, but it will boot.
I can also see that you have a 16K RAM card. You can take one of the 8 identical RAM chips on the right side of the card and put it in the empty RAM socket on the motherboard. Then you should have the full 48K.
Thanks I suspected that. So I suppose there was a language card in this machine at some point. What does a language card do? I think we might have one somewehere.
However I did try that and it did not change the behaviour. I also tested the Floppy EMU and it wouldn't read so that removes the drive from the equation.
Can you - or someone - explain me what's the boot process of an Apple //? Would it be the same of an Apple //e if the auto-boot ROM is installed?
With no cards, you simply get a beep and a Basic prompt:
APPLE ][]■Try to find the missing Language card. It probably has the missing RAM chip.
The language card adds another 16KB of RAM to your system, so it has 64KB. And if it's an original Apple Language Card (not a clone) then it will also contain a newer version of the boot ROM with the "autostart" feature. Another reason to be looking for the missing card... :)
ah ok so there is something wrong with it then as I tested it without that row of RAM.
I will try to find the language ROM but we might not have it.
So what about testing/replacing the ROMs?
Having a missing RAM chip will not prevent the computer from working unless it's in the bottom row. You're missing chip will only disable the top row and leave you with a 32K machine.
As for the ROM, you might want to take a look at the ROMX .
I don't think the system is smart enough to realize it has only 32K complete if just one chip is missing unless I'm mistaken, which is possible.
I think, but I'd have to try it to verify that with no disk (boot device) installed it will go to Applesoft (or IntBASIC) but any memory access in the 3rd bank will be bad because one bit will be missing of every byte. Since the Apple II doesn't do any kind of memory checks to speak of it will work up to a point.
A missing chip in the 3rd row will cause DOS loading to fail unless the DOS is INITed for 32K or a MASTER.
I think the reason why you have to INIT for a particular size is that's the only way it knows where to try to load DOS. I'm not sure how a MASTER disk knows what the memory size is 32K or 48K (since DOS 3.x doesn't know how to load to a 16K language card without additional software). I suspect it does some kind of memory test in software loaded with the DOS boot process. Like trying to write bytes and read them back maybe? I don't remember if I knew at one time.
BASIC (both flavors) will do a memory check and set HIMEM accordingly. That's the only way the computer can detect how much memory it has. And a single bad/missing RAM chip will disable the entire row.
Gotcha.
However I did try removing the remaining 7 ICs and I still end up in Monitor. So I feel there is an issue here.
ROMX looks cool but really I don't need the extra features it brings. Is there a writable IC I could use to replace the ROMs, possibly with no or little modification? And what is the easiest way to check those ROMs with the TL866? I'm still puzzled that I need an inverter to read them, that would have been added in the IC library, no? I see the latest T48 programmer can use 25V to program, maybe upgrading my TL866II to the T48 would be a good option?
Also I tried connecting a drive to the system. It does change its behaviour a bit: no drive = double beep and monitor. Drive = it sits on "Apple ][" doing nothing until I hit RESET, then it lands on monitor.
I think start from a working set of RAM and confirming the ROMs are working should be my priority.
Unfortunately, if you replace the ROMs with EPROMs you are going to need adapter sockets (with inverters) for each chip. That will cosrt way more than the ROMX. You could also butcher the motherboard with your own EPROM modification but that's a bit more difficult.
Ok I need to understand this a bit more.
The original ICs are PROMs if I understand correctly? Particularly 2316B. My TL866II+ doesn't even read them so I sold it and ordered the T48.
Once I have it, I can at least check the ROMs against known good images.
If one ROM is defective, which IC can I use and will it require an adaptor regardless?
I see the RomX for the Apple II is $50 but I am in the UK so it makes things a bit more complicated.
Meanwhile I watched the last two videos of Adrian's digital basement and I see how the Apple II should boot, which is a step forward :)
|Thanks!
I stand corrected on that. It's been too long, I didn't remember all of that. I still think the part about DOS 3.3 boot failing on a 32K matchine if it was INITed on a 48K machine is true unless you used MASTER CREATE. Somehow I have a weird recollection of that being needed. Let me know if that is wrong also.
The TL866 won't read some of the weird old PROMs like a 2316 w/o an adapter. but that's true of a lot of them. I don't think that just to read a 2316 chip you need an adapter with an actual inverter though, the simplistic ones made with two sockets should probably work.
The T48 programmer looks interesting though. I will have to see if there is Linux support for it.
Not sure if it will read a 2316B either though. It seems to be touted as the next iteration of TL866. It looks like it may support some newer chips that the older versions don't. But FWIW, support for extremely old chips, the original TL866CS that I have will program a lot of 27xx chips that the newer TL866-II that I have won't. However, I've found the TL866-II seems to do a better job on some GALs. So I keep both.
Any IC that has a customer part number and copyright (e.g. "APPLE") is not a programmable anything. It was manufactured with data permanently wired at the fab as a Mask ROM.
These were sometimes called "mask *programmable" chips, but the term is confusing, because there is no way for a device programmer to write to them, and they never existed as a blank device.
You will not find bipolar PROMs used in any Apple II. They simply hold too few bits and are too expensive and laborious to program.
The T48 features Vpp up to 25V but you're right the 2316 is not on the list. LOL!
The T48 should be able to program those old 27XX which the TL866-CS used to be able to program.
Well, the out of pocket in the upgrade is £15 so I was just looking for an excuse to buy one.
I might email Xgecu, there is no need why the programmer shouldn't read the 2316. However, the 2316 datasheet says "pin compatible with 2716" and the 2716 is supported by the T48 *AND* the TL866II. So I am wondering if Xgecu just needs to fix the profile for the 2716 :)
Am I mistaken in thinking that the 2316 is not rewritable but the 2716 is - though with 25V Vpp - and which also needs to be UV erased? In that case, wouldn't I be able to replace a faulty 2316 with a 2716?
Reason I am asking is that the T48 supports the 2716 and I do have the UV light.
https://www.dmcmillan.co.uk/blog/testing-apple-ii-europlus-roms/2316%20Datasheet.pdf
Yes you can replace the 2316 with a 2716 EPROM. But you will need to use an adapter to re-map a couple of the pins. At the bare minimum you can do this with two sockets (see Sather, "Understanding the Apple II" page 6-15). Without an inverter however, there will be a conflict with the Apple ROM and Language Cards as well as any other board that uses the INH signal. So you should always use a proper adapter.
If you want to read a 2316 ROM in your programmer, ReActiveMicro does make an adapter.
Except for the DISK II controller board...
You are correct on this. The INIT command creates a "slave" diskette which needs at least as much memory as the system that created it. And won't use any excess memory if booted on a larger system.
Thank you. That chapter is what I was looking for to understand.
So Apple programmed those 2316 so that CS is active high - while 2716 are active low, hence the need for the inverter, even for the programmer to just read them.
Let's move in steps: first let me check those ROMs. For that I just need a inverter which I can borrow from the Apple itself. The T48 is on its way anyways - I sold my 866II in 2 hours and the T48 is not expensive so that's a "nice to have" anyways.
IF some ROMs are bad, I could either use RomX or I could make my own adaptor (which has an inverter on the PCB) and program some 2716, bearing in mind that not all 2716s are the same. Am I correct?
To test the RAM, which other device uses 4116 ICs? I can't use my Apple //e, can I? Or the Commodore 64. I remember there was an Arduino sketch to test those chips, maybe I can take a look.
Are there any Diagnostic ROMs I could use with the Apple II?
Thanks so far!
Just stay away from the TI 2716; it is not compatible. But a TI 2516 will work.
There are plenty of RAM testers like the Arduino one you mentioned but they don't always find every bad chip. Some may pass the test but still fail when used in the Apple II.
As for Diagnostic ROMs, there is an Apple Diagnostic Card but they're hard to find. Or the MultiROM card. But honestly, the ROMX includes a dead RAM Memory test, a full, burn-in quality RAM tester, as well as the Apple Diagnostics Program in one of its ROM banks. I know the shipping cost is an issue - maybe you can find a used one locally.
are those open source projects? I might think of putting one together for my toolbox.
If anyone want a Apple II Diagnostic Card I have a couple available for €55 plus €15 postage doesn't matter where you live. Alternatively you can just use the eBay link
https://www.ebay.com/itm/125980776422?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=BxWC1D9HRTK&sssrc=4429486&ssuid=BxWC1D9HRTK&var=&widget_ver=artemis&media=COPY
There's also the original Centronics Interface card and their original Parallel Printer card. (These were two distinct cards.)
Plus Apple's original serial interface card, the version before the "super" serial card.
And don't forget Apple's 1982 combo Printer/Centronics card, which employed an LS472 to double the quantity of bipolar PROM in order to include the firmware from both the Centronics Interface and Parallel Printer cards.
(In short, there are a lot of Apple branded cards that use bipolar PROMs. A lot of third-party printer cards do too.)
Well the RomX is a tad expensive to ship so I'll think of alternatives :)
romx.JPG
You can also boot without any of the ROM chips if you have a MultiROM card. I have one for sale that I don't need any more. I bought it when I also thought that something is wrong with my ROMs. They turned out to be fine and I wouldn’t be surprised if yours are fine too. PM me if you are interested. Shipping it from Bulgaria to the UK will not be more than $7.
MultiROM.png
MultiROM card.JPG
Hi,
I've built myself a "ROM replacement" adaptor.
https://oshwlab.com/kris.garrein/apple-ii-rom-replacement-board_copy
I wanted to test the ROM on my Apple //e and if not mistaken this adaptor won't work there so I wanted to whip one together just to make sure the ROM is working - so I know it should work on the unhappy Apple II.
I cannot find a schematic of the adaptor needed, can someone point me to the right direction please?
Also, is there a pre-made ROM for a 27C256? I can try to append together the ones I find online as directed in the manual but I suppose someone must have done this before!
I'll also test Adrian's digital basement ROM which seems very good!
Finally, I have several 27C512. Can I use them leaving half of the ROM empty?
Thanks!