disk ii card and other questions

24 posts / 0 new
Last post
Offline
Last seen: 1 month 3 weeks ago
Joined: Jan 25 2020 - 18:59
Posts: 6
disk ii card and other questions

Hi everyone,

(Introduction - problem starts after 2nd paragraph if you would like to skip this)

I am new here and am working on repairing/restoring an old apple ii plus that was gifted to me as a kid for something to play with that didn't work. Amazingly, my childhood self managed to not break anything more or touch the ICs. I was in school for computer engineering, but have been away for a few years due to health problems. So while I have a break for a few weeks from doctors while they come up with a new plan, I decided to keep busy as much as I am able to.

 

I got the system working, and so far have been able to find authentic parts other then two logic chips (an AND gate and an octal buffer). Those I had to replace with new modern day versions of the ICs. Not sure if this decreases the overall value of something like this? I also have the original integer ROMs and Programmers aid, which I verified on a ROM burner using a converter board I made to go to the M2716 EPROM ICs. These seem to be working in the ROM card I have now that I fixed the logic gates that were dead. The Integer basic boots and I ran a few quick program lines and it seems to be functioning. It appears to me that someone plugged something into one of the card slots that was bad and it took out parts on all the cards and a few parts on the motherboard. I have a language card that I am working on getting together and a joystick.

 

So now my questions and the problem.

 

Questions:

1) If I recall the language card needs to go in slot one so it can't be used with the ROM card. Is there any way around this? If this isn't a simple answer then I would be willing to do some research myself if someone could point me in a good direction.

2)Are there other ROMs that work with the ROM card other then the Integer Basic ROMs. You don't need to list them here, but maybe point me in a good direction to look.

3)I just wanted to verify the order for disk drives that I found while doing research. I appears that you can install up to 6 drives by using slots 6, 5, and 4 in descending order. I assume the computer will still always use slot 6, drive one as the drive to boot from with autoStart? Can you mix and match 13 and 16 sector cards?

4)Anyone have any good websites to find parts for the apple II+ on? Or any place to get time period correct parts such as the logic chips I mentioned earlier (an AND gate and an octal buffer)? Right now I am using Mouser, Digi-Key, and Newark for most orders including other projects, but these are obviously not time period correct parts.

5)Anyone know of any good resource that lists/shows all the possible expansion cards available for these (and their purpose) back when they were mainstream? There are a few I was curious about.

 

Problem:

So the problem I have is that about half or more of the disks I have require the 13 sector PROMs for P5 and P6 (I believe 341-0009 and 341-0010) to be readable. I don't have a disk card with these. I only have the 16 sector ones. I am working on getting a Franklin disk card controller which should let me read these, since it can switch from 13 to 16 sector modes. That said I would really like to get my hands on the original PROMs. The computer had these originally, but these were in a box of spare parts that came with the computer and the pins were almost all torn off (it looked like someone tried to piggy back it to a 16 sector ROM and messed up). Below are my questions about this.

1)Does anyone have any of the original 13 sector PROMs they would be willing to part with?

2)Does the Franklin card go in slot 6 and replace the disk ii card?

3)I found a few blank (I think) TBP28L22N ICs. I believe these are the same chip used in the original apple ii plus disk ii cards for the PROMS. I know it wouldn't have the apple copyright or ROM code stamp, but at least it would function correctly and be the correct original IC. If I sent these to someone could they burn the binary files into them for me? The ROM burner I have doesn't support this IC, and right now buying a new ROM burner isn't really an option.

4)I seem to recall there was a way to make the DOS 3.3 16 sector software that was on the floppy read the 13 sector discs and run them. I can't seem to remember how to do this though. If anyone could help me here or point me to a resource that would be awesome. I would like to rule out bad floppies too and it would be nice to see what is on these in the meantime.

5) In research I think I saw that you could piggy back the 13 and 16 sector PROMs with a switch on their enable pins in order to allow the same card to read both types of floppies as long as it was switched when the system was off?

 

Lastly, as a side note. If anyone has any extra disk ii floppy drive cables, I could use one if the price is right. (One of my two drives has a bad cable)

 

I greatly appreciate any help anyone here can give, as well as your time in reading through this post. Thank you in advance.

 

Thanks,

 

Jonathan

 

Offline
Last seen: 9 hours 13 min ago
Joined: Dec 20 2003 - 10:38
Posts: 416
When 16 sector proms came out

When 16 sector proms came out apple provided 2 programs. Boot13 and demuffin. Boot13 let you boot 13 sector disks. Demuffin was for converting 13 sector to 16.

Offline
Last seen: 1 month 3 weeks ago
Joined: Jan 25 2020 - 18:59
Posts: 6
Boot13

Hi Wayne,

 

I think Boot13 is probably a good place for me to start. Is this something on DOS 3.3? Or is this a separate disk I need to be looking for?

 

Thanks again.

Offline
Last seen: 9 hours 13 min ago
Joined: Dec 20 2003 - 10:38
Posts: 416
It's a program on the DOS 3.3

It's a program on the DOS 3.3 utilities disk. I think it came with every II+

Offline
Last seen: 7 hours 28 min ago
Joined: Jul 5 2018 - 09:44
Posts: 478
Wayne wrote:

When 16 sector proms came out apple provided 2 programs. Boot13 and demuffin. Boot13 let you boot 13 sector disks. Demuffin was for converting 13 sector to 16.

 

I think you are just thinking of MUFFIN, which came on the DOS 3.3 System Master.  DEMUFFIN (and ADVANCED DEMUFFIN) were mods which were used for things like cracking copy protection.  There was also a 3rd party utility called NIFFUM which could convert files from 16 sector to 13 sector disks.

 

 

 

 

 

 

 

Offline
Last seen: 9 hours 13 min ago
Joined: Dec 20 2003 - 10:38
Posts: 416
Now that I'm thinking,

Now that I'm thinking, painful as it is. Yes, Muffin was the program for converting from DOS 3.2 to DOS 3.3.

I beleive Demuffin converted the opposite way

Offline
Last seen: 1 month 3 weeks ago
Joined: Jan 25 2020 - 18:59
Posts: 6
I will try the Boot13 on the

I will try the Boot13 on the DOS Master when I have some time this weekend. Although I would like to try to get a disk ii card with the actual 13 sector ROMs on it.

 

I found a few blank (I think) TBP28L22N ICs. I believe these are the same chip used in the original apple ii plus disk ii cards for the PROMS. I know it wouldn't have the apple copyright or ROM code stamp, but at least it would function correctly and be the correct original IC. If I sent these to someone could they burn the binary files into them for me? The ROM burner I have doesn't support this IC, and right now buying a new ROM burner isn't really an option. Just curious if anyone on here has any way to burn these old ICs or any resource they could point me to for doing this?

Offline
Last seen: 7 hours 28 min ago
Joined: Jul 5 2018 - 09:44
Posts: 478
cmpen18scijm wrote:

I will try the Boot13 on the DOS Master when I have some time this weekend. Although I would like to try to get a disk ii card with the actual 13 sector ROMs on it.

 

I found a few blank (I think) TBP28L22N ICs. I believe these are the same chip used in the original apple ii plus disk ii cards for the PROMS. I know it wouldn't have the apple copyright or ROM code stamp, but at least it would function correctly and be the correct original IC. If I sent these to someone could they burn the binary files into them for me? The ROM burner I have doesn't support this IC, and right now buying a new ROM burner isn't really an option. Just curious if anyone on here has any way to burn these old ICs or any resource they could point me to for doing this?

 

Many Disk II controller cards I've seen came with the MMI 6309 chips in them but the TI 28L22 was also used by Apple.  These chips are fairly hard to find, but you may find some new old stock 6309 here:

 

https://www.electronicsurplus.com/mmi-6309-1j-ic-memory-ttl-256-x-8-prom

 

Unfortunately the burners that can burn bipolar PROMs like the Apple P5/P6 (256x8) are pretty rare these days.  I don't currently even know anyone who has one.  I used to know someone who had a Data I/O 29B who used to burn them for me, but I've lost track of them over the years.  It requires quite a bit of juice to pop the tungsten fuses used in a lot of these devices and most of the modern burners just can't do it, even if you could rig up an adapter socket to handle the small DIP package.  I've occasionally seen a set of original 13 sector PROMs for sale, but usually not cheap.  I also knew a few people back in the day that had modified their disk controller cards to handle either piggy backed chips or a larger size PROM with a switch to select 13 or 16 sector boot.  There was at least one 3rd party controller card that did the same thing as they used a single EPROM with plenty of space instead of the two smaller PROMs.  I think it was a 2708 or 2716 they used.

 

 

Offline
Last seen: 1 month 3 weeks ago
Joined: Jan 25 2020 - 18:59
Posts: 6
SoftwareJanitor,

SoftwareJanitor,

 

Thank you for the information. I guess if I want a physical card for 13 sectors I will either need to make one with modern day components. Or get lucky and find original PROMs that are burned. Or I will need to make a burner for the older parts that interfaces with a modern day computer system. I was going to school for Computer Engineering, so I think I probably have the skills to do one of these options and have the PCBs printed overseas and mailed to me for assembly to keep cost down. I could etch them here, but I currently don't have the correct protective gear for handling the chemical process in its entirety and no access to a lab (although as my health improves I am building a lab to do custom work like this).

 

I appreciate the information though. These old systems are difficult to find parts for and find good sources of knowledgeable accurate information. They are also not taught at all in college.

Offline
Last seen: 7 hours 28 min ago
Joined: Jul 5 2018 - 09:44
Posts: 478
A possible idea would be to

A possible idea would be to build a small adapter board which would plug into the PROM sockets on a Disk ][ Controller Card, but provide the data from a modern chip.  You could then use something like an EEPROM or a conventional EPROM and have something that would be easy to program on a modern system.

 

Offline
Last seen: 1 month 3 weeks ago
Joined: Jan 25 2020 - 18:59
Posts: 6
SoftwareJanitor,

SoftwareJanitor,

 

Thank you for the idea. I have done this to some other projects I have restored and for purposes of reverse engineering. I normally do this as an absolute last resort when restoring systems, or if I just need to test something. I find that some people aren't happy with these types of modifications being done in a restoration.

 

As an update. I may have found someone locally that has an old burner that they can use to help me burn a set. Or I may attempt to build something so I have it for future restorations.

 

Thank for again for all your time and help. I appreciate it.

Offline
Last seen: 9 hours 13 min ago
Joined: Dec 20 2003 - 10:38
Posts: 416
There were some aftermarket

There were some aftermarket disk II controllers controllers that used an EPROM instead of a prom. One of those would likely be easy to clone. Some of the cards with EPROMs would sense whether a disk was 13 or 16 sector and work that way

Offline
Last seen: 7 hours 28 min ago
Joined: Jul 5 2018 - 09:44
Posts: 478
If you are doing a

If you are doing a restoration and you want the computer to actually be usable I'd just stick with the 16 sector PROMs.  Most of the software that anyone would want to run on a ][ or ][+ is on 16 sector media.

 

Offline
Last seen: 7 hours 28 min ago
Joined: Jul 5 2018 - 09:44
Posts: 478
Wayne wrote:There were some
Wayne wrote:

There were some aftermarket disk II controllers controllers that used an EPROM instead of a prom. One of those would likely be easy to clone. Some of the cards with EPROMs would sense whether a disk was 13 or 16 sector and work that way

I

 

II think that it was either Rana or Micro Sci that worked that way.  I don't remember right now.  However if he is doing a restoration then a 3rd party controller or even more a modern recreation of that probably isn't what he wants.  Frankly, there is little reason to put 13 sector PROMs in a machine that is anything other than a shelf weight, and even then, most would not know the difference without looking up the part #s.  Most of the software was 16 sector, and a computer with the 16 sector PROMs can use BOOT13 to run 13 sector software.  As far as I know there was never a BOOT16 to run 16 sector disks on a machine with 13 sector PROMs.

 

Offline
Last seen: 9 hours 13 min ago
Joined: Dec 20 2003 - 10:38
Posts: 416
Instead of building a card

Instead of building a card from scratch, one of the ones with EPROMs could be built using one of the protoyping cards.

I uploaded a couple of pics of the cards

https://drive.google.com/open?id=1qJbesS7zsf_oWNaggLLZqdtXgXpBPToC

https://drive.google.com/open?id=1FI69F12ez3ae1IHeVj-OL2_sNBXTPi7_

Offline
Last seen: 1 month 3 weeks ago
Joined: Jan 25 2020 - 18:59
Posts: 6
Hi Everyone,

Hi Everyone,

 

Thank you for all your help and suggestions. I may try the EPROM method at some point. I was able to use BOOT13 for some disks. I also found an old franklin disk card that I was able to use to read the others. I think this solves this for me for now. I will work on getting this system put togeather and then put it in storage for now.

 

Thank you again.

Offline
Last seen: 7 hours 28 min ago
Joined: Jul 5 2018 - 09:44
Posts: 478
Wayne wrote:Instead of
Wayne wrote:

Instead of building a card from scratch, one of the ones with EPROMs could be built using one of the protoyping cards.

I uploaded a couple of pics of the cards

https://drive.google.com/open?id=1qJbesS7zsf_oWNaggLLZqdtXgXpBPToC

https://drive.google.com/open?id=1FI69F12ez3ae1IHeVj-OL2_sNBXTPi7_

 

I don't recall ever seeing one quite like the first example.  That one wastes a ton of EPROM space considering that most likely only 256 bytes of the 2048 on each EPROM is used.  If I was building a card like that I'd at least probably put in a switch to allow flipping between 13 and 16 sectors.

 

I do remember seeing ones similar to the 2nd one.  Again, it would probably not be too hard to have a switch to allow 13 or 16 sector operation.  The 2708 would be fully used then.  The only problem with a 2708 based design is that those are much harder to find these days than a 2716 and even fewer burners will program them.  My Minipro TL866CS, for example won't, because I believe they normally require 25V for programming.  I can burn 2716 all day.  I still think the 2nd design is probably better, but I'd adapt it to use a 2716.

 

Edit to add, now I'm kind of scratching my head about the 2nd card.  the 82S135 chip is another PROM.  Weird that you'd need that AND the 2708? 

 

After re-evaluating it, if I was going to clone one, the 1st card actually looks easier to source the parts for.

 

 

 

 

 

 

Online
Last seen: 1 hour 56 min ago
Joined: Jun 18 2010 - 13:54
Posts: 209
Although P5 and P6 are each

Although P5 and P6 are each 256 byte PROMs, that doesn't mean you can combine them into a single 1K or larger EPROM. One holds the boot code and the other implements a state machine. Each operates independently with its own address and data lines.

 

Also don't forget that the TI 2716 requires three programming voltages as opposed to every other 2716.

Offline
Last seen: 9 hours 13 min ago
Joined: Dec 20 2003 - 10:38
Posts: 416
I didn't realize the 82S135

I didn't realize the 82S135 was another PROM. I have a number with 1 EPROM and 1 PROM. Main reason I included the second was that 2708s are harder to find whil 2716s are pretty easy to come by

Offline
Last seen: 7 hours 28 min ago
Joined: Jul 5 2018 - 09:44
Posts: 478
Wayne wrote:I didn't realize
Wayne wrote:

I didn't realize the 82S135 was another PROM. I have a number with 1 EPROM and 1 PROM. Main reason I included the second was that 2708s are harder to find whil 2716s are pretty easy to come by

Yeah, both are incredibly interesting cards.  I love some of the weird clone gear.  You are absolutely correct that 2708 are hard to find and almost even harder to find a programmer these days that can handle them.  If someone was designing a new board using 2716s would be a better choice.

 

macnoyd's picture
Online
Last seen: 6 min 54 sec ago
Joined: Oct 15 2012 - 08:59
Posts: 514
I am able to program 2708

I am able to program 2708 EPROMS. (fyi)

Offline
Last seen: 7 hours 28 min ago
Joined: Jul 5 2018 - 09:44
Posts: 478
macnoyd wrote:I am able to
macnoyd wrote:

I am able to program 2708 EPROMS. (fyi)

What programmer do you have?  I haven't seen any reasonable priced ones with good software support that can handle them. I can't justify spending hundreds of dollars on a programmer and ones that only work with Windows are essentially useless to me since I don't have a Windows box to run it on.

 

I don't have a good source of 2708s.  I have a few old ones, but I don't know where to buy any new ones.  I have been able to find 2716, 2732, 2764, etc.  But I haven't seen any 2708 anywhere in a long time.  By the mid 1980s they were seldom used in any new designs and by the 1990s they were already harder to find.

macnoyd's picture
Online
Last seen: 6 min 54 sec ago
Joined: Oct 15 2012 - 08:59
Posts: 514
I have a limited supply of

I have a limited supply of 2708's and I program them using a DATA I/O System 25B.  Some that I have are the coveted Intel white ceramic devices along with various others.

There are a lot of them on eBay at the moment:

https://www.ebay.com/sch/i.html?_nkw=2708+EPROM&_in_kw=1&_ex_kw=&_sacat=0&_udlo=&_udhi=&_ftrt=901&_ftrv=1&_sabdlo=&_sabdhi=&_samilow=&_samihi=&_sadis=15&_stpos=03431&_sargn=-1%26saslc%3D1&_salic=1&_sop=12&_dmd=1&_ipg=200&_fosrp=1

 

2708's were a PITA even in their day due to the power supply requirement.  They became unpopular after the 5v only devices arrived.  No surprise there.

I'm happy to program them up for ya if you have the need.

I might even have an Apple ][ Programmer that does these as well.  Gotta look...

 

Offline
Last seen: 9 hours 13 min ago
Joined: Dec 20 2003 - 10:38
Posts: 416
You can find 2708s on ebay.

You can find 2708s on ebay.

The Apple II Apparat EPROM programmerwould do 2708 EPROMs. At least thats what the manual says. I've never actually tried mine with that size.

Log in or register to post comments