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XF551 upgrade question

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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

 

Could you post pics? It would be nice to see if it can be duplicated with regular old school flat drive cables.

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Could you post pics? It would be nice to see if it can be duplicated with regular old school flat drive cables.

It would be very easy, the flat piece of circuit board functions as a gender changer, allowing the XF drive cable to be extended. The extension cable provided by CSS has a 34-pin card edge connector that connects to this circuit board, another 34-pin card edge connector for the 5.25" drive, then a 34-pin rectangular IDC socket connetor for the 3.5" drive. The 2 wires for the drive select are attached to this gender change circuit board, but could be connected to the floppy drive header pins instead.

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Here we go.

You can see the small board and the 2 wires.

The 2nd pic is the box. The one in background is for the flippy disk and write protect.

 

James

post-9587-0-93325900-1399364597_thumb.jpg

post-9587-0-28506200-1399364626_thumb.jpg

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I believe the cable at the joiner end has been moved over 1 before being crimped on to make the signals work out properly.

 

james

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Fascinating.....

 

Now if we only had the actual part # of the chips inside the black box, schematics, etc. I could definitely recreate the drive connections but without them or at least part of them it's a shot in the dark.

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This is peculiar. I had my upgraded XF551 as D2, plugged into my 800XL. Into the other SIO port was my AtariMax SIO2USB connector. Yesterday, it wouldn't boot anymore, APE wasn't showing any activity.

 

Troubleshooting it tonight, it looks like the one SIO port isn't working anymore. I thought that was odd. Where do I look first on trying to figure out what's wrong?

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This is peculiar. I had my upgraded XF551 as D2, plugged into my 800XL. Into the other SIO port was my AtariMax SIO2USB connector. Yesterday, it wouldn't boot anymore, APE wasn't showing any activity.

 

Troubleshooting it tonight, it looks like the one SIO port isn't working anymore. I thought that was odd. Where do I look first on trying to figure out what's wrong?

The traces to the SIO ports on the XF551 are poor quality, it's likely a trace between the 2 ports has broken(a known weak point). Check for continuity between pins on the 2 SIO ports, if you find broken traces simply solder jumpers wires between corresponding circuit board pins on the 2 ports as replacement.

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Hello guys

 

Haha, I knew I had to have it somewhere, but was under the impression that I didn't have an online version.

 

Sincerely

 

Mathy

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Where do I look first on trying to figure out what's wrong?

What BillC said. Upon close inspection of the underside of one of those SIO jack pins you might find a solder ring has separated from the trace that used to carry the signal to the other jack and the circuit of the drive as well. My opinion is that the single sided board is of course crap, but the main culpret here is the very cheap and weak rivets used to hold the jacks to the board to begin with. Once they start to move and they always do, you'll be in there a dozen times upside down using another short, small, solid wire (1/8 watt resistor lead or smaller) laid down in solder on top of the scraped clean broken trace trying to get continuity back between the two jacks. I would move into repair mode and fix it all right now while you've only got one trace broken and not all of them - and that will happen eventually if it's not fixed right.

 

To fix it right you must unsolder both jacks to absolute perfection, each pin must be seen to move when wiggled independently first, then remove the rivets and jacks, clean up the jack pins and reassemble with aluminum pop rivets which will require a larger size hole in at least the jack IIRC. I also like to put some JB weld between the jack and board when going back together, but this is not required by any means and too much makes for difficult soldering and a big old mess too. Eventually you'll even have the same problem with the power jack depending on how many times you plug it in making that one another question of just a matter of time anyway, so while there I just desolder it too and definitely glue that one down with JB weld since it doesn't have any other way of being held down except the solder connection. After the epoxy has cured completely, then re-apply solder and fixes to broken traces for the final time you will need to do this. They work real good if they can't move and an aluminum pop rivet is all it takes for that to happen, I do use backup washers sold right next to the rivets themselves, under both sides of the rivets and this requires a longer rivet for the two washers, but it's worth it since the rivet goes together with such a draw that it will pull thru the plastic of the jack and possibly even crack the cheap board under the small rivet head unless the load is distributed across the face of the washer keeping that from happening. PITA, but it's all you can really do to have one of these that will last like the rest of your Atari lineup will.

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I pulled the board and you could tell where the solder had hairline fractures on the bad SIO port. I resoldered all of them and the drive is back in business. I'm just never going to remove the cables from that drive if I can. :-)

 

Thanks everyone!

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I'm just never going to remove the cables from that drive if I can. :-)

This seems to me a good idea and a sensible way of avoiding fractures on the connector. The SIO connector on my first XF was so tight I never pulled that end of the cable out, and as a result I never had a hint of trouble with it for the past 25 years.

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After researching SIO connectors and hubs, I think I'm just going to start adding cat 5 jacks to my equipment. Almost all devices only require 5 lines, and if I have anything that doesn't work over the 5, I still have my SIO port.

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So to add dual drive functionality to an ordinary XF551 without the epoxy module, you'd need to disconnect DS0 from MO and run jumpers from DS0 and DS1 to the two unused pins on the microcontroller? Trying to jumper the drives to DS1 and DS2 is kind of an ugly hack, and most 3.5 drives out there can't go beyond DS1, if they can have their drive ID changed at all. (It probably doesn't even matter from the software's perspective.)

 

I also didn't realize that the XF551 ROM was only 4K in size. The schematics show that a 2764 is hooked up, but only half of it is actually used. Some of the CSS upgrades come on 2732 EPROMs, but the dual drive ROM comes on a 2764 with the two different versions of the ROM on it, selectable by jumpering the high address pin.

 

Does Bob Puff want to release his firmware to the public domain, or does he still want to make money from it?

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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.

Nitromors is the stuff to use if you're really curious after the inside of a potted module. It's a gel based paint stripper that can be used to break down epoxy-based potting compound. Available from DYI shops, about $ 10 per liter. Never used it myself, but rumour has it this stuff works well.

I dont't know if it works to remove resin potting. That can be removed with a heat gun and metal tools, but only as a last resort. The components will probably not survive from the heat and mechanical strain of chipping. This method will do if you just intend to reverse engineer a circuit or recreate a PCB.

 

re-atari

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