1200XL Rev.B OS / FSM

[Ricky Spanish]

Heard lot's of thing over the years about what Rev.B actually does, everything from older

games compatibility to a rewritten OS.

According to the 1200XL field service manual, Rev.A is only to be replaced with Rev.B if:

 

1. Rev.A EPROM or ROMS have failed.

2. If the consumer has complained about the improper function of the

SYSTEM RESET key. 

 

Goes on to say:

There are no other differences between Rev. A and Rev. B

 

Apparently the (R) on the splash screen is an easy ID marker.

 

Just found this information interesting & wanted to share.

[ACML]

Rev B (Rev 11) has major compatibility improvements.  There are several titles that will not run on Rev A (Rev 10), but will on Rev B.  The reset issue has to do with the delay on boot WRT to the 74LS14.  Some 1200XLs will intermittently cold start at SYSTEM RESET when a warm start was supposed to happen.  Rev B has a longer delay, like the 600/800XL OS that allows the 74LS14 to get to it's minimum threshold voltage which ensures a warm start.  Every 1200XL should upgrade to Rev B (Rev 11) or better yet, the 600/800XL OS that has maximum compatibility and retains all 1200XL F1-F4 key and L1/L2 LED functions.

 

Edited May 23, 2023 by ACML

[+x=usr(1536)]

1 hour ago, Ricky Spanish said:

Heard lot's of thing over the years about what Rev.B actually does, everything from older

games compatibility to a rewritten OS.

According to the 1200XL field service manual, Rev.A is only to be replaced with Rev.B if:

 

1. Rev.A EPROM or ROMS have failed.

2. If the consumer has complained about the improper function of the

SYSTEM RESET key. 

 

Goes on to say:

There are no other differences between Rev. A and Rev. B

 

Apparently the (R) on the splash screen is an easy ID marker.

 

Just found this information interesting & wanted to share.

 

Where in the service manual did you find this?  The copy that I'm using only states the following:

 

This is something I'm definitely curious about, and if I missed it please let me know where that info is found.  The version of the field service manual that the page was taken from is attached.

Atari_1200_XL_Home_Computer_Field_Service_Manual_Rev01.pdf

[_The Doctor__]

if you replace eproms with eproms, or roms with roms you don't need to change anything...

if you replace an eprom with a rom or a rom with and eprom then you must change the jumpers.

[Ricky Spanish]

...

 

Edited May 23, 2023 by Ricky Spanish

[Ricky Spanish]

Edited May 23, 2023 by Ricky Spanish
clarity

[+x=usr(1536)]

8 hours ago, Ricky Spanish said:

 

Interesting - the Tech Tip in your manual is dated Sept. 29, 1983; the one in mine is dated July 12, 1983.  This one supersedes the earlier one.

 

Can you please attach the version of the 1200XL Field Service Manual that you have to the thread?  The only version I'm aware of being openly-available is the one that I have, so if there's a different one floating around it'd be appreciated.

[+x=usr(1536)]

While digging around, I came across a different scan of the Rev. 01 1200 XL Field Service Manual on archive.org.  This one is a lot clearer than the one that I posted earlier in the thread, which looked to have possibly been scanned from a photocopy.

 

The scan quality of this one is much better and adds another five or six pages of info at the end.  Nothing earth-shattering; mostly just diagrams designed to aid in the identification of ICs and their part numbers.  Still useful, though.

 

Paging @www.atarimania.com in case this is of interest 

Atari_1200XL_Home_Computer_Field_Service_Manual_Rev01.pdf

[SoundGammon]

Can someone post the roms here for downloading? I'd like to burn a set!

[DrVenkman]

5 minutes ago, SoundGammon said:

Can someone post the roms here for downloading? I'd like to burn a set!

There are plenty of threads about Rev 11 and the ROMs should be easily found with a forum search. That’s what I did several years ago when I put Rev 11 into one of my 1200XLs. 

[+x=usr(1536)]

Having poked around in this a bit more, I'm increasingly of the opinion that some misinformation made its way into the Tech Tip between the version (July 12, 1983) that I posted and the one that @Ricky Spanish posted (Sept. 29th, 1983).

 

If anyone happens to have original Rev. 11 (aka 'Rev. B') 1200XL OS ROMs with the Atari part numbers printed on them, could you please verify the part numbers?  It's understood from the Tech Tip and elsewhere what they should be, but verification would be appreciated.

 

Anyway, both versions of the Tech Tip were published several months after the Rev. 11 ROMs were released in Dec., 1982.  The first version advised replacing EPROMs with ROMs, but made no mention of using the Rev. 11 ROMs as part of that process - it recommends part numbers C060616 and C060617, which are the Rev. 10 ROMs.  However, the subsequent revision explicitly states to replace Rev. 10 EPROMs or ROMs with Rev. 11 ROMs (part numbers C060616B and C060617B), but hinges that replacement on whether or not Reset button flakiness is being experienced.
 

In other words, the goalposts have been shifted from 'replace the OS with the same version if EEPROMs were used instead of ROMs' to 'replace the OS with the new version if the Reset button is flaky regardless of EEPROMs or ROMs being installed'.

 

The working theory is that the revised Tech Tip is correct in that Reset button problems are a symptom of the Rev. 10 ROMs, but it's incorrect in saying that this is all that it fixes since we know there are significant differences between the two beyond just that issue.

 

As for why this is the case, I can only speculate.  However, it would have saved Atari a reasonable chunk of change if they didn't have to potentially swap out the OS ROMs in 250,000 computers due to compatibility issues.  By making replacement require Reset button problems in order for the swap to be approved under warranty, they were able to mostly sidestep having to address the compatibility issues under Rev. 10 at no cost to the customer with Rev. 11 replacement.  Still, that's only speculation, and I'd rather not attribute to malice that which can be explained by simply screwing up the docs - especially when there's nothing solid to support the idea.

[reifsnyderb]

The source code revision modifications just state that several problems were fixed.  lol

 

;*        Revision 10 (1200XL)
;*        Support 1200XL, add new features.
;*        H. Stewart/L. Winner/R. S. Scheiman/
;*        Y. M. Chen/M. W. Colburn    10/26/82
;*
;*        Revision 11 (1200XL)
;*        Fix several problems.
;*        R. S. Scheiman    12/23/82

 

A quick compare, through the source code, shows at least a lot of re-organization....

 

aa1r11.s

aa0r10.s

 

 

[+kheller2]

I'm confused by people's confusion.

 

The original R10 was on EPROM.

Then it was released on ROM.

Then R11 was released on ROM.

 

TT18 talks about a failure of an EPROM and how to replace it with the then in the supply chain ROM: 11/B

TT18A talks about gripes of the reset button. But if you read the description it could be related to any incompatibility gripe.

 

The rest issue has been discussed here a few times, and the source code is also available to look at what changes where done.

 

The reset problem is not a symptom of R10, per se.  One could argue, the problem is the board and software fixed it.

 

But yes, one could read into TT18A that Atari specifically targeted the reset issue to avoid a "recall".

 

Also note that TT18A was published months after the 1200XL stopped production, and there are very few units that have R11 installed.

 

 

[+x=usr(1536)]

2 hours ago, kheller2 said:

I'm confused by people's confusion.

I kinda was too, until digging into it.  More:

2 hours ago, kheller2 said:

The original R10 was on EPROM.

Then it was released on ROM.

Then R11 was released on ROM.

 

TT18 talks about a failure of an EPROM and how to replace it with the then in the supply chain ROM: 11/B

TT18A talks about gripes of the reset button. But if you read the description it could be related to any incompatibility gripe.

All of which is true, but there isn't really one good place to refer to that lays it out in summary like this.  Searching for the info also isn't totally intuitive since doing so successfully would rely on having some prior knowledge of the mechanics of the situation to begin with.

2 hours ago, kheller2 said:

The rest issue has been discussed here a few times, and the source code is also available to look at what changes where done.

True, but for most folks they're probably not going to dig into it, assuming that they even know that it's available.

2 hours ago, kheller2 said:

The reset problem is not a symptom of R10, per se.  One could argue, the problem is the board and software fixed it.

 

But yes, one could read into TT18A that Atari specifically targeted the reset issue to avoid a "recall".

 

Also note that TT18A was published months after the 1200XL stopped production, and there are very few units that have R11 installed.

All of which are valid points.

 

Much of this could make for a good update to the Atari 8-Bit FAQ since it would give a single point of reference for the question in the future.  I'll get in touch with the maintainer and see if he thinks it's a good fit; if so, I'll write something up and submit it.

[Ricky Spanish]

6 hours ago, x=usr(1536) said:

Can you please attach the version of the 1200XL Field Service Manual that you have to the thread

Sure thing:

 

1200XL FSM.PDF

[+x=usr(1536)]

27 minutes ago, Ricky Spanish said:

Sure thing:

Thanks for that; it's very helpful.  By any chance do you happen to remember where it came from?

 

From a quick glance, it looks as though there are at least three versions of the manual floating around:

• The "photocopy" version.  This is the B&W one I had been using up until today.  It appears to have been scanned from a photocopy of the manual (hence the name), and fold-out circuit diagrams are immediately inside the cover.  The Tech Tips that it contains are 15 (June 7th, 1983), 12 (June 16th, 1983), 18 (July 12th, 1983), and 19 (August 15, 1983).
• The "blue-green" version.  This is the one I found earlier today on archive.org.  It seems to have been scanned directly from an original manual, and the covers are reproduced in a blue-green colour.  The fold-out circuit diagrams in the photocopy version are not included.  Tech Tips are the same as in the photocopy version, but this one includes component identification charts after the Tech Tips which are missing from the photocopy version.
• The "newer" version.  This is the one that @Ricky Spanish was referring to earlier in the thread and posted above.  It appears to have been scanned from a different original manual than either the photocopy or blue-green versions and lacks the fold-out circuit diagrams.  Tech Tips are 12 (June 16th, 1983), 15 (June 7th, 1983), 18A (September 29th, 1983), and 19 (August 15, 1983).  No component identification charts are included.

Note that I haven't done an in-depth comparison of all three so don't know what the extent of their respective differences may be, but a few things seem likely:

• The photocopy and blue-green versions are probably the same manual, but with each having additions and omissions of its own.
• The newer version is likely that - newer.  This is based entirely on the presence of Tech Tip 18A (September 29th, 1983) vs. Tech Tip 18 (July 12th, 1983).
• Whether or not the newer version would also have included the fold-out circuit diagrams and component identification charts is unknown, but it seems likely that it may have.

 

[Ricky Spanish]

12 minutes ago, x=usr(1536) said:

Thanks for that; it's very helpful.  By any chance do you happen to remember where it came from?

Unfortunately I do not. 

I have another 50 page manual with every schematic/diagram/pin layout you can think of for the 1200XL. 

Saved my arse on a couple of occasions. 

 

[+x=usr(1536)]

7 minutes ago, Ricky Spanish said:

Unfortunately I do not. 

I have another 50 page manual with every schematic/diagram/pin layout you can think of for the 1200XL. 

Saved my arse on a couple of occasions. 

Definitely attach it if you can.  I'm guessing it may be Sams Computerfacts, but even if it's one we've already referred to here it can't hurt to have a few of them in one thread.

[Ricky Spanish]

6 minutes ago, x=usr(1536) said:

Definitely attach it if you can.

K, not sure if it's been posted already but here it is:

 

1200xl.pdf

[+x=usr(1536)]

14 minutes ago, Ricky Spanish said:

K, not sure if it's been posted already but here it is:

Oh, yeah, that one.  Kinda forgot it existed.

 

The best way to think of that one is as being something of a third-party remaster of the original manual.  The OCR and scan work was cleaned up and replaced with more-readable text; new circuit diagrams drawn by Jerzy Sobola (the 'jer' referenced on the cover) replaced the original Atari ones.

 

Being perfectly straightforward, I would only keep this one around as a manual of last resort.  By no means do I say that to diminish Sobola's work, which, overall, was excellent, but they are known to have inaccuracies that didn't exist in the originals.  There's no list of which machines and/or peripherals this applies to, so it's generally safest to assume that his diagrams may not be 100% accurate.

 

Note that I'm by no means implying that Atari's diagrams never contained mistakes; they certainly did.  However, those are typically known quantities with known corrections at this point.

[Ricky Spanish]

13 minutes ago, x=usr(1536) said:

Oh, yeah, that one.  Kinda forgot it existed.

Guess I got lucky on it saving my arse eh ? LOL.

Anyways glad to contribute. AFAIC the 1200XL is the ultimate 8-bit computer  

[+x=usr(1536)]

7 minutes ago, Ricky Spanish said:

Guess I got lucky on it saving my arse eh ? LOL.

Totally understood - I've used his diagrams in the past to fill in certain gaps left by other manuals or documents.

7 minutes ago, Ricky Spanish said:

Anyways glad to contribute. AFAIC the 1200XL is the ultimate 8-bit computer  

They are, aren't they? 

[Gunstar]

The 1200XL can be the ultimate 8-bit, once a few minor changes and upgrades are made.

 

 

 

 

Atari 1200XL system

1200XL internal upgrades:
PBI, APE Warp+ 32-in-1 OS, XL/XE MMU, Internal BASIC, Dual POKEY stereo with pre-amp board and stereo headphone output, SuperVideo 2.1 video upgrade, +5v SIO fix, Hi-speed SIO mod, keyboard fix, Pal GTIA conversion board, PAL GTIA, PAL ANTIC, cartridge port mod, Internal RGB LED lighting.

1200XL external upgrades:
Syscheck XL 2.1 PBI board with custom case: (4 OS switcher, 512K sram (576K total system ram)), Super SDX cartridge (SDX 4.8, battery backed Real Time Clock), MyIDE II cartridge: (full PBI compatibility, 512K sram, MyBIOS 4.9, FAT32 partition, APT partitions for SDX HDD drives 5-15, On-board OSS language carts and diagnostic SALT roms), RIX break-out-box audio/video output.

1088K total programmable memory internally & externally!

Peripherals:

1050 disk drive with Happy double density Warp speed x3 57K SIO, built-in 1050toPC and SIO2PC RS232 com ports, front drive # switch and SIO activity LED's, internal LED lighting

1050 disk drive with Happy (see above) and front drive # switch, internal LED lighting.

1030 modem

1020 plotter

1010 tape drive with Rambit Turbo-tape upgrade, Stereo external I/O mod, Power switch mod, SIO activity light mod.

CA-2001 DD 180K Indus GT clone drive with built-in CP/M mode with 64K memory. Custom XL paint job

"1027" R.D. XL/XE eprom burner supporting 2732-27512 eproms with custom XL case.

SDrive-MAX SIO2SD floppy drive emulator w/custom XL case

Panasonic KX-P2023 24-pin dot-matirix printer w/custom XL paint job

 

 

More here 

 

 

 

Edited May 23, 2023 by Gunstar

[Ricky Spanish]

51 minutes ago, x=usr(1536) said:

They are, aren't they? 

Absolutely ! Great design, great keyboard, no built-in basic, side mount cartridge, & 2 ROM slots ! <- surprised somebody wiser than me hasn't attempted a custom 16Kx2 OS. 

[DrVenkman]

12 minutes ago, Ricky Spanish said:

surprised somebody wiser than me hasn't attempted a custom 16Kx2 OS

I'm sure a few people have over the years, but there are even better solutions than that these days: Ultimate 1MB adds 4 OS slots, 4 8X "BASIC" (or other 8K cart) slots; PBI interface and support for cart-based IDE hard drives; and built in SpartaDOS X. Then there's the Atarimax 32-in-1 board which gives 32 different OS slots.