1050

No, that's what they said. They said it's just the right size to slide right up in there and stay put too. Got me curious to give it a try someday. Someday never came. I still have a pack of felts I haven't used up yet, but I can see a day when they don't have them anymore and something is still required. This would be comp.sys.atari.8bit days when MyDeja ran the UseNet archives, before the google buyout. Back when windows 98 was the internet. They got properly flamed and quit posting about it, but I was still curious. Those posts are still up there called google groups today.

It's built in to the spring tension adjustment steps shown from the backside partially in your third picture posted in this thread. I've played with it, but I could not find that it made any noticeable difference so I doubt the previous owner could cause the dirty head today at all. I run mine on the lowest pressure since it doesn't seem to affect anything here, your mileage might differ however. You can sacrifice some felt pad life by scraping a sharp knife blade across it at 90 degrees very lightly. It will loosen some of the felt fibers that could be carrying some of that goo. Your call, you do you. You'll just have to keep cleaning the head again at any rate. And the disks may clean up eventually. Pretty sure it's just collected aerosols in the air where they were stored and not much to do about that. Although there is normal deterioration of the oxide surface as the major component of the brown goo. As a way out there side note: The Faculty 1998 scifi teen movie -- my rating 4 stars Ever since 1998 when Bic corporation learned that high school kids could use their famous Bic pens to store and dispense drugs with, they have super glued the end cap on which used to be removed and used by a minority of Atarians as a replacement felt pad on the 1050. Didn't appear to be harmful and at least the few that would admit doing so didn't follow up with any disaster stories. End of my knowledge on the subject, I never tried it and figured if I ever did want to do that, I could just buy yet another pack of 19 cent pens and I'd be good to go. By the time I got a pack, the movie had been out for years and the end cap is simply unremovable ever more. Might be possible to destroy the pen with pliers to pick the hard plastic away, but never needed to go there myself. No clue if that style of pen is still available either.

https://www.amazon.com/dp/B0CCF3C1YF Is all you needed, I'll assume the rest is useless tracking information.

http://www.atarimania.com/documents/rambo_manual.pdf Is one source for the instructions. ATB in your project.

The 9E0 region is the Woolley density switching code, but your copy has been stepped on, last three bytes of line 9E0 are supposed to be FF, FF, FF. And 9F0 continues the altered density switch code. Full details in the comp.sys.8bit link within this link https://atariage.com/forums/topic/206780-xf551-35-mod/?do=findComment&comment=4226046 So it appears to be my bad, the new file discovered a few more pages after the above link is unique, but it is not the PAL version as I thought. Which I foolishly renamed wrong here and lead everyone on a wild goose chase. We've all had the PAL version all along, apologies to MrFish as his 38B97AE3 is correct in it's file name being for NTSC and PAL machines alike with all changes applied by Atari including the found by phaeron endless format loop with the homage to the 1050 within it. Apologies to Philsan as well, your file is the same as MrFish and the one I always thought was the problem child 38B97AE3. Yes, it is the latest PAL rom and it does work with NTSC too. So my offerings in the other threads are based on the wrong thinking. Here are density switching versions of the proper 38B97AE3 (7.7) roms for the XF-551 drive. Woolley density switching 7_7 roms.zip

It has some but not all of the 7.7 enhancements. Comparing files H:\1STXP\!LEE\ATARI\XF551\XF551_C101696 REV 7.7.BIN and H:\1STXP\!LEE\ATARI\XF551\CONVERTED XF551 V7.4.ROM 0000069F: C4 FB 000006A0: C0 A8 000006C0: B8 FF 000006C1: 77 FF 000006C2: F0 FF 000006C3: D3 FF 000006C4: 10 FF 000006C5: 96 FF 000006C6: D3 FF 000006C7: C8 FF 000006C8: F0 FF 000006C9: D3 FF 000006CA: 50 FF 000006CB: 96 FF 000006CC: D3 FF 000006CD: 76 FF 000006CE: D1 FF 000006CF: A4 FF 000006D0: 16 FF 000006D1: 04 FF 000006D2: 1C FF 000006D3: FB FF 000006D4: A8 FF 000006D5: C4 FF 000006D6: A1 FF Your file above, CONVERTED XF551 V7.4.ROM had to have the last half of it replaced with zeros in order to NOT have the above file be a mile long and just no need for that, so I converted to have that last half be zeros instead of FF as all the other XF-551 rom files are done. So there are other parts changed the same as 7.7 but 7.4 wasn't quite good enough it appears. So it would appear that both you down unders with the 50 Hz power grid and PAL machines can use 7.7 Rom and if so then that answers which is the PAL version - 7.7 with a CRC-32 of D438B4D9. You get the above if you'll use a MS-DOS command called file compare. fc /b file1 file2>difference.txt and the difference.txt between the files is above, cut and pasted. /b is the binary switch to avoid text file comparisons and since I'm not keen on the text files or their differences, I use /b. NT windows continues the tradition of MS-DOS commands in their command.com file. It works the same in all windows with NT having much more powerful and feature filled batch file methods than 9x DOS mode could ever dream of. The string of FF in your 7.4 file (on the right side) is where Atari went back into it and made the differences in 7.7 (on the left, file1) to make it work for PAL systems. This 8040 code is filled with lots of "blank" spots of FF which is handy for doing exactly the above with. Thanks for answering the PAL question for me guys.

First look at them and both are a roy-al mess with the extra cheese. Somehow what looks like to be Atari ROM character set data has overwritten the file links and while also becoming a part of the file where the file links are still intact remarkably. Boggles the mind wondering just what did happen and when/how. Especially on these two, if you have ONE or TWO needful things off these - speak up and give them a name because this will be severe work to recover anything of any part of them. Those files will have holes in them and no way to recover what was in the hole before the shotgun went off. Unless... Is there any chance you can make other ATRs using a different method or program/hardware line up? It would be interesting to compare those results with these results. But I hold little hope at the moment.

An inordinate number of XEGS have been found with OS ROM that are faulty. Since you've tried this one about every way except upside down, I'm leaning towards the opinion that it has a faulty OS ROM chip and replacement would be my next step. A 27256 Eprom with a speed of 200ns would be perfect and of course a $40 eBay programmer to burn the file onto it with. The TL866II plus seems popular but I see it's 60 dollar range now. A standard eprom that would do nicely for $5.95 https://www.jameco.com/z/D27256-Intel-Corporation-IC-27256-25-EPROM-256K-Bit-250ns-Production-UV-Erasable-PROM_40061.html And a One Time Program only (OTP) type for $3.49 that would also work fine. It won't have the quartz window for erasure, but instead just be like any other chip with dark plastic top on it. But you only get to program it once, and that's exactly what Atari bought in the first place. https://www.jameco.com/z/AM27256-1D-Advanced-Micro-Devices-EPROM-OTP-256K-32Kx8-8-Bit-200ns-5V-DIP-28_2303055.html So you can program PAL, GAL and many other types of eproms beside the 27256 with the programmer above. In addition you can place a logic chip that has the numbers sanded off of it in the device and it will tell you what the number was. And you can change the game in there if missle command isn't your first choice. Perhaps lot's to think about.

Yes, thanks. More information than I had before. So I could be misremembering my specs here easily. If it's bad news, I'll be back. For now assume I don't remember too good a subject I used to know like the back of my hand, but since I haven't had one in my lap for 2 decades, I'm a bit rusty on those devilish details. A while later ... A mitsumi D503 is correct for the XF-551 and it was my mistake to suggest otherwise above. As a 360K drive only, it can not be set to any other RPM than the one it is made for which is 300 RPM. But I'll see if I can find a jumper diagram for it anyway. One never knows what can be found today VS what was found yesterday, the link provided at the end is a perfect example, I've never seen the two letter abbreviations used so simply graphed ever before this - I can actually understand it. I saved the page as an MHTML so I might make use of this new understanding later. More time away ... Only thing I can scare up about jumpers for the D503 is there are two drives on eBay currently at $799 for the pair. They are new, never used, and have consecutive serial numbers for those that would mock the collector value added as a tad bit excessive. So jumpers for a mitsumi d509 are shown here, hopefully it's at least interesting info. https://www.embeddedsw.net/EMUFDD_MITSUMI_Jumpers.html Please note that it's jumpered to be drive DS1 above and to work in the XF-551 it needs to be DS0 unless you modify some traces. A DS1 drive can be made to work on the XF-551 if work is applied, but Atari shipped them all as DS0.

You can't. The ram is built into the 8040 or 8050 CPU which ever you have running the show. And the RPM is a perfect 300 RPM as per IBM spec, you can't set it even if you do get to find out what it is. Trivia moment, the compatibility with 288 RPM drives comes about by overclocking the CPU oscillator by that same 4% difference and we gets the same disk from either. So some PC drives can be jumpered to be either 300 or 360 RPM. Unlikely yours has been fooled with, but just for grins can you find the make and model number for that PC drive mech and post it here? Should be a sticker or glued on paper tag on the frame somewhere. Most are mitsumi D309. But most any 360K 5.25 inch drive can work in these. There is also a possibility that someone prior has popped in a 1.2 meg 5.25 drive in there and that's the real issue as they don't work well here. Make and model number should give a direction and maybe I can scare up a jumper diagram for it too. IIRC, 360 RPM is for the high density that 1.2 meg drives can do with HD floppies, but they can also do 360K density at the slower RPM and data rate. They are trouble due to half width heads as it's capable of 80 tracks instead of our normal 40.

If the Ready light is blinking in time sync with motor turning on and off then there is a Power On Self Test (POST) failure that is catastrophic - read as you won't get it do anything else until the main issue has been resolved. It's made to do that, so something is working right at least. Top of the list for things gone wrong is commonly suggested as a bad RIOT chip, U7 a 6532P, the large one on the right side. Other issues can cause it too, such as chips needing reseating in the IC sockets with some DeOxit wetting the legs of the chips. http://www.atarimania.com/list_documents_atari-400-800-xl-xe-_8.html http://www.atarimania.com/documents/Atari DOS 2.5 - 1050 Disk Drive Owner's Manual.pdf http://www.atarimania.com/documents/Service_Manual_for_the_Atari_1050_Disk_Drive.pdf http://www.atarimania.com/documents/Atari_1050_Disk_Drive_Sams_Computerfacts_Technical_Service.pdf

Ok. Should have done the power jack just to cover the bases there, it's a common issue too. Use your DeOxit on the drive select switches and work the devil out of them while still wet. Let dry and work the devil out of them again. It's rare on the XF-551, but they can still be as much trouble as they are on the 1050 which I have to do every ten years at least. Next is change out the two smaller ICs, U3 a 74LS38 and U4 a 74LS14, they may have gone soft for some unknown reason. https://www.jameco.com/z/74LS38-Major-Brands-IC-74LS38-Quad-2-Input-NAND-GATE-Buffer_47693.html https://www.jameco.com/z/74LS14-Major-Brands-IC-74LS14-HEX-SCHMITT-TRIGGER-INVERTER_46640.html Just a heads up for the times we live in these days, but Jameco is selling grab bags of these "glue" logic chips. 100 for $15 or 400 for $50. They aren't making them anymore it would appear. You don't happen to have a spare 360K 5.25 drive for a PC handy do you? Eventually, it will be very nice to swap out the mech and see if that helps any. All in due time, so no hurry on any of it or the order of it.

They actually suffer far more from cheap rivets than being skimpy on the solder. These are the same SIO jacks used on the 800XL and we have zero issues there because it's a double sided board to solder too, but mostly because of higher up management wasn't keen to cheap out on worthless rivets until the XF-551 came along. I drill out the rivet holes so they will take a standard aluminum pop rivet with washer and get the jack mounted solid first so it won't ever move again. THEN I do the reflow. The power jack will need some grey epoxy to firm it up as it tends to wiggle around too. And that's when the solder connections develop the issues. Solder advice alone is a poor fix because then it just keeps on happening.

My input would be to place some ferrite beads on the output leg and glue them on with super glue. Then perhaps place a couple .33 uf chip bypass capacitors to shunt RF signals on both the power to ground planes and output to ground plane. Seems to be areas quite available if you'll scrape a bit with a sharp knife. Don't think this one is radiating EMF too much, that's pure operating loss and while it's always possible, the effective field is well constrained in the inductor design from day one and I don't expect it's being overpowered to any significant degree to cause uncaptured magnetic lines of force to heat my coffee up with. Selecting Decoupling Capacitors for Atmel’s PLDs http://ww1.microchip.com/downloads/en/Appnotes/DOC0484.PDF A decoupling capacitor is also known as a standard bypass cap when you shut off the aggrandizement double speak filter. Why people insist on the buffalo approach as a way to explain something pretty basic is a curse of the ego run amok. At any rate, our Atari are using the glass encapsulated (bodgy/dodgy) .1uf standard unit, commonly marked as 104 (10 and four zeros for 100,000 pico farads) very often and they always were inadequate in the first place. They took a perfectly good chip capacitor and put axial leads on it and then rolled it up inside a glass case such that it looks very much like an old school diode.

Hi Mathy, Yeah, that'll work, thanks. Don't worry about the page layout too much, it's a common thing to need a table top sized document when reading the fine print on these anyway. Not as bad as the 130XE version, but I can only read it in places where I already know what it says, they didn't try very hard did they? Where you been keeping this one at? Is there a story about how you came to be keeping it to yourself all this time?