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XF551 upgrade question

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I was going through a 17 year old eBay purchase and found a CSS upgrade box with a chip. The chip was by Atari, so that means in another box I must have a XF551 upgraded drive. I found it, but it's not complete. I don't know what this little box thing is for:

zupy5ate.jpg

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It looks like a CSS (Bob Puff) XF551 drive upgrade. These came as single 360 KB, single 720, and dual 360/720 and 720/720. This is a very versatile and fast upgrade.

 

http://www.nleaudio.com/css/products.htm

 

If I understand your question, the potted "box" is his way of copy-protecting the items he produced. The potted "box" usually contained another IC of various types.

 

-Larry

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Nice find! Wish I could incorporate it into my XF551 remake project. No schematics, parts # etc. I contacted Bob Puff for permission and info. He initially seemed interested but after a few emails back and forth he 'disappeared' and I never heard from him again. Kinda sad. It would be a nice save. :(

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Hello Lenore

 

Try calling him. I tried emailing a couple of times, didn't work. But calling always does.

 

Sincerely

 

Mathy

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I was going through a 17 year old eBay purchase and found a CSS upgrade box with a chip. The chip was by Atari, so that means in another box I must have a XF551 upgraded drive. I found it, but it's not complete. I don't know what this little box thing is for:

zupy5ate.jpg

As already answered it's an XF551 single 3.5" drive upgrade. You're missing the 3.5" mechanism/mountingbrackets and the top of the case. I don't know about later 3.5" HD mechanisms, but the early ones are backward compatible with DD discs. CSS shipped a 1.44MB Sony mechanism when I purchased my XF dual drive upgrade, but this was over 20 years ago. The XF551 uses DS0, moderm floppy drives are configured as DS1.

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I have the top piece and the bracket for the drive. I'm going to dig out a 3.5" drive and fire her up. Should be awesome!

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It really does work well, and is very stable. I think I've still got a couple of these "new in the bag," but then CSS may still have some also.

 

BTW, the dual drive upgrade allowed you to run both drives off the XF551 pcb. For years, I ran an XF551 (5-1/4") with a 3-1/2" slave drive. IIRC, the slave is automatically 1 drive number higher than the master.

 

-Larry

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I'm pretty sure that I actually built that upgrade...I worked at CSS in the late 80s/early 90s.

 

The black plastic shells came in sheets of ~20 or so. I'd build up enough of the product's "guts" to fill an entire sheet, we'd stick the upgrades in the shells upside-down, then pour some rather obnoxious-smelling epoxy into each shell to seal it up. Next day, I'd cut the shells out of the sheet and package them up for sale.

 

Unfortunately, I no longer have any of the reference materials or knowledge I used to build up the guts of that thing, so I can't tell you exactly what's inside that shell. I do remember that the "shelled" upgrade products all had at least a couple of ICs stacked on top of each other, with jumper wires running between various pins.

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Success! I pulled a drive out of an old PC and set the jumper to DS0 and it works! (After I found a disk that would actually format.)

 

It's an 1.44MB mechanism, but it appears to work fine as a 720KB drive.

 

atyqu8y8.jpg

 

Unfortunately, the face plate with the carrier didn't match up, so I need to find one that does.

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I just finished my XF-351 upgrade, I used the Stephan Dorndorf Hyper-XF rom for 3.5 drive.

 

I desoldered the idc connector from the board and soldered in male connector so I can use regular floppy cables.

 

I disassembled the drive; painted the face plate, 3.5-5.25 faceplate adapter and top and bottom of the case to match the XE colors. The drive case was severly yellowed, almost to the point it could match an XL :)

 

 

I washed the parts, Put on rubber gloves, wiped them down with alcohol, used the Testors Model paints, First Primer, then Light Sea grey which is very close to XE color. After the paint was applied, I baked the parts in the oven on its lowest setting (160 Degrees) for about 15 minutes to help it dry thouroughly.

 

It looks like a true Atari released drive.

 

Best Regards

Robert

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I can post photos tomorrow when I fly back to Michigan, currently in North Carolina for work. In the same pic, I will include my un-painted XF-551 to show how close the colors match.

 

Robert

Edited by venom4728a

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20140502_162428.jpg

20140502_162358.jpg

20140502_162452.jpg

20140502_162713.jpg

 

Here are some pics of my XF's 3.5 is painted with Testors Light Sea Grey, 5.25 is un touched and slightly yellow.

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That's fine paint job. I would have found it hard to tell which unit had been painted from the photos alone, were it not from the discolouration on the 5.25" drive. Really good work and thanks for sharing the photos.

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Thank You!

 

I did some spray trials on the inside of the drive cover, where it had not yellowed. The color is pretty darn close.

 

I actually found out about this color for XE/ST from this thread from 2007.

 

I have used retrobrite on my STE, and considered doing this drive case too. But, the drive face and adapter plate would still not match, so I decided to try to find a paint so all the parts would be the same color.

 

Robert

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I'm pretty sure that I actually built that upgrade...I worked at CSS in the late 80s/early 90s.

 

The black plastic shells came in sheets of ~20 or so. I'd build up enough of the product's "guts" to fill an entire sheet, we'd stick the upgrades in the shells upside-down, then pour some rather obnoxious-smelling epoxy into each shell to seal it up. Next day, I'd cut the shells out of the sheet and package them up for sale.

 

Unfortunately, I no longer have any of the reference materials or knowledge I used to build up the guts of that thing, so I can't tell you exactly what's inside that shell. I do remember that the "shelled" upgrade products all had at least a couple of ICs stacked on top of each other, with jumper wires running between various pins.

 

Were the markings ground off of the ICs? Were they ordinary TTLs or were there any PALs/PLD/microcontrollers?

 

The MAME guys have gotten better at dealing with epoxy blocks over the years, so they might be able to give some advice as a last resort.

 

Also, I'm guessing that the purpose of the box is to add the second drive select signal, which according to the schematics is missing from the board and is needed to run a second drive.

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Were the markings ground off of the ICs? Were they ordinary TTLs or were there any PALs/PLD/microcontrollers?

 

The MAME guys have gotten better at dealing with epoxy blocks over the years, so they might be able to give some advice as a last resort.

 

Also, I'm guessing that the purpose of the box is to add the second drive select signal, which according to the schematics is missing from the board and is needed to run a second drive.

 

I never ground the markings off of the chips...they were encased in epoxy, so there wasn't a whole lot of concern that somebody might be able to successfully disassemble them. :) I honestly don't remember for sure what was in the XF551 upgrade...it's been a long time. If I had to guess, I'd say an EPROM and either a TTL or a PAL. The Super Archiver was built in the same fashion, but was more complicated due to it needing to be socketable. I seem to recall a PAL, an EPROM, and maybe a 2K RAM chip in the SA?

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Were the markings ground off of the ICs? Were they ordinary TTLs or were there any PALs/PLD/microcontrollers?

 

The MAME guys have gotten better at dealing with epoxy blocks over the years, so they might be able to give some advice as a last resort.

 

Also, I'm guessing that the purpose of the box is to add the second drive select signal, which according to the schematics is missing from the board and is needed to run a second drive.

The upgrade of the drive being discussed in this thread is the single drive upgrade, there is no drive select circuit. CSS also made a dual drive upgrade which includes the extra circuitry, using DS1/DS2 to select the mechanism.

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The upgrade of the drive being discussed in this thread is the single drive upgrade, there is no drive select circuit. CSS also made a dual drive upgrade which includes the extra circuitry, using DS1/DS2 to select the mechanism.

 

Any ideas how they accomplished it?

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Any ideas how they accomplished it?

I do have a CSS XF dual drive upgrade, and it is similar to the single drive upgrade with 2 wires from the module connecting to the ribbon cable to provide DS1/DS2 drive select. The 8040/8050 MPU used in the XF551 have 24 I/O pins, and I assume they are using 2 of these to provide the drive select signals with others being used for the copy protection circuit. The signals used for the drive select could also be used as part of the copy protection circuit during POST.

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The upgrade of the drive being discussed in this thread is the single drive upgrade, there is no drive select circuit. CSS also made a dual drive upgrade which includes the extra circuitry, using DS1/DS2 to select the mechanism.

Very interesting, I hadn't bothered reading the OS label before and just assumed it was a dual because of the epoxy widget. So this means the epoxy widget still did OS software interlock verification on the single drive systems too since it's purported purpose was for drive switching of one or the other mech. Wonder if there is anything interesting to learn from a dump of this OS chip? Puff put in some extra code in these that would at least read IBM/ST disks as well. Other than the Happy, no other drive could dream of this way back then. And of course you really meant DS0/DS1 since the 1772 doesn't do DS2 or DS3.

 

Dropcheck, there is an unused single bit pin of an I/O port on the 8040 that got addressed by Puff's OS code which also allowed for two concurrent drives to answer commands and respond with or receive data, if the low drive was addressed a zero was stored in that bit of the port and if the high drive was addressed a one was stored. That bit pin of the port was then jumpered to the 1772 FDC drive select input pin that made it all happen. This signal line went thru the epoxy widget so as to obfuscate a plain jumper's existance, but a plain jumper is all that is required there. Simple enough concept, but 8040 code is anything but simple to work with. If you want your own software interlock verification code to go uncracked like Puff's still is today, you've got your work cut out for you. I personally don't see the need for the double dog seekret decoder ring approach since someone would have to cook up an XF-551 board to use it on anyway and that's what you'll be selling, you still make money even if a few scoundrels make off with the dual drive version code for it and roll their own dual drive rigs at home. Just a thought I had, having no clue to what you are thinking along those lines other than you want to offer it if possible. It would be very nice to see a dual drive XF-551 on the market again too, they just didn't make enough of them the first time around.

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Very interesting, I hadn't bothered reading the OS label before and just assumed it was a dual because of the epoxy widget. So this means the epoxy widget still did OS software interlock verification on the single drive systems too since it's purported purpose was for drive switching of one or the other mech. Wonder if there is anything interesting to learn from a dump of this OS chip? Puff put in some extra code in these that would at least read IBM/ST disks as well. Other than the Happy, no other drive could dream of this way back then. And of course you really meant DS0/DS1 since the 1772 doesn't do DS2 or DS3.

I mean that the CSS XF dual drive upgrade uses DS1/DS2 since Atari connected DS0 direct to MOTOR for drive select, which means that it can't be deselected for use in dual drive operation without physical modification. I purchased my dual drive upgrade with a 3.5" mechanism, and there were instructions on how to rejumper the Mitsumi 5.25" to DS1. The XF551 uses the Intel 8040/8050 processor and not the WD1772, and the actual drive selects used are just a matter of which pins to connect to on the floppy drive connector. To use a DS1 drive in an XF551 single drive configuration it would only be necessary to jumper the MOTOR or DS0 pin to the DS1 pin.

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I have both a duel drive and xf upgrade for 5 1/4 from css. The duel drive has a double sided edge connector with 2 wires soldered to it for ds2, ds3 . A cable connects to this board for the 2 drive mechs.

The single drive upgrade uses the black blob for copy protection of the eprom code. The code for this however is easy to find and disable.

 

James

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