XF551 drive question

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Geister
Posts: 6
Joined: Fri Dec 15, 2017 4:04 pm

XF551 drive question

Post by Geister » Thu Dec 21, 2017 4:04 pm

Hi, I recently decided to get back into Atari computers and bought some units at a local surplus store I bought an 800XL with a 1050 drive (unmodded), and a 130XE with an XF551.

Everything is as Atari sold them with the exception of the XF551. It has a 3-way toggle switch installed in the front panel of the drive. The drive seems to only work normally with the switch in the central position. Does anyone know of a common mod for this drive that uses a 3 way switch?

I also bought some used floppy disks from the same place that appear to have Atari software on them, but the 1050 cannot read them. I don't have access to the XF551 at the moment, but I suspect that the disks were formatted double sided/ double density. Maybe they just died over time. I never had an XF551 before so I'm not very familiar with them.

I'm working on building an SIO2PC (USB) cable using a DTFI board. Any tips on getting it to work?

Also, any old Abe's Aces members on here?
Geister
Posts: 6
Joined: Fri Dec 15, 2017 4:04 pm

Re: XF551 drive question

Post by Geister » Tue Dec 26, 2017 9:32 pm

No guesses on the toggle switch? Well, I guess I'll be taking it apart to see what it's soldered to.

Here's another issue I could use some guidance on.

I bought several used game cartridges from a place called 2nd and Charles. All worked except for Asteroids. I know I can download most of these carts as ROM images, but I'd like to have the thing working, if possible.

The metal part of the cart had a ding in it, but the internals appear to have been undamaged and show no signs of corrosion. Is there anything that I should be looking for in the way of damage? Do the cart ROMs ever just die of old age?

I'm ringing out the traces from the sockets back to the edge connector, and so far, everything checks out. Both ROMS are socketed, I suppose that the chips could have been swapped by a curious previous owner, but how could I tell? Do the numbers on the chips tell where they should be? There are two similar numbers on the chips, C45036 and C45037. The one ending in 036 is in the left socket and the one ending in 037 is in the right. Is there a cross reference between Atari part numbers and cartridge games?

I'm still wondering if there are any old ABES ACES members out there (with the emphasis on old)?
Geister
Posts: 6
Joined: Fri Dec 15, 2017 4:04 pm

Re: XF551 drive question

Post by Geister » Thu Dec 28, 2017 1:59 pm

Well, the Asteroids cart seems to be fixing itself. :D

It's not 100% yet, but I'm thinking the problem is contacts in the cart slot. I've got to get some of that DeOxit spray.

I hope everybody had a great Christmas and will have a great New year!
Geister
Posts: 6
Joined: Fri Dec 15, 2017 4:04 pm

Re: XF551 drive question

Post by Geister » Sat Jan 06, 2018 10:57 pm

Anybody still alive on here?
Well, I had the XF551 apart to fix a cracked solder joint at the power plug. While I had apart, I traced the wired from the switch on the front. It basically takes two wires to ground.

The two wires on one side of the switch going to jumper wires on the top side of the single sided board. The one jumper is marked D0 & and the other I think is D1. The third wire goes under the board and is soldered directly to the ground plane. I suspect that the switch overrides the drive select switch although I can't think why it would be useful to do that.

The drive seems to work fine except I cannot get it to format a floppy. The floppies I'm trying to format don't seem to be readable, so they may just be crap disks. I'm not going to try to format the disks that I can read until I can back up the files on them to another location.

I've hooked the SIO2PC cable I'm building to the PC and installed the drivers and respeQT recognizes it on COM4. With a loop-back between RXD and TXD I can type into a terminal program and watch the activity lights blink on the FTDI board, and the letters I typed appear in the terminal. So far, so good. I have to get the pins for the SIO connector I 3D printed so I can wire up the Atari side to go any further.

That Asteroids cartridge is still flaky, but working most of the time. I still need to get DeoxIT to see if it helps.

Later!
Geister
Posts: 6
Joined: Fri Dec 15, 2017 4:04 pm

Re: XF551 drive question

Post by Geister » Sat Jan 20, 2018 8:55 pm

Hi, Me again.

Well, not much has changed with the XF551. It still can't format a disk, but the 1050 drive was able to format a disk that I thought was unrecoverable, and I was able to write and read files from both the 1050 and the XF551. I'm hoping that someone can give me an idea about what may be the problem. I may be looking to buy some new old stock disks to see if I can format them, but I'm only seeing HD disks, and I seem to recall that there were problems using HD disks with Atari drives. Maybe I'm wrong, but my funds are limited so I don't want to throw money away on a maybe.

On a brighter note, I hand wired the the FTDI to the SIO port on the 800XL and tried it with images on my laptop. It worked perfectly on the first try. I'm hoping to eventually get an image of DOS XE up and running so I can try the fabled DS:DD mode. I got out of Atari before the XF551 was widely available and DOS XE had not yet been announced. However, I've been reading that the SIO2PC might not work with an actual drive attached which might make it hard to load DOS XE and attempt to format a disk on the 551! Anybody know any different?

I've also posted some questions on the AtariAge forums, but either I've pissed everybody off by breaking some arcane forum rules or they are too busy with their three dimensional tesseract-based Atari emulators to be bothered with a noob playing with old news like an SIO2PC?

I'm going to try hooking up the XF551 as D2: tonight and wire the FTDI to the second SIO port on the drive Either it will work, it won't work, or it will let the smoke out of something and make me cry.
Geister
Posts: 6
Joined: Fri Dec 15, 2017 4:04 pm

Re: XF551 drive question

Post by Geister » Fri Apr 20, 2018 12:44 am

To anybody still browsing this forum and wondering if I ever got everything working... the answer is mostly yes.
The SIO device works as expected and I can actually use it to create floppy disks, or just run images of software from the PC. Cool beans!
The XF551 is 100% and so is the 1050. Using Spartados, I can format double sided, double density 360k floppies. I understand the I can also get a mod for it to run a 3.5 inch floppy with 720K. That would have been totally awesome in 1985!
The only thing I have left to do is get the power switch working correctly on the 130XE and then I might start modding the the computes. I might also get a 600XL to mod so I have a small footprint unit which might help with the space problem I have.
Mostly, I've been working on the Altirra emulator because of lack of room to set up the Atari equipment where I don't have to tear it down and move it out of the way. I need a man cave!
This will probably be my last post on here since everybody seems to post on Atari Age, and only uses this website for its awesome resources. If you see me on Atari Age, say hi.
Vulcanman
Posts: 3
Joined: Thu Jun 25, 2015 2:16 pm

Re: XF551 drive question

Post by Vulcanman » Thu Jan 10, 2019 8:24 pm

Hi Geister,

just read your post, and it's nice to see you have everything working (touch wood).

Do you have any pictures of the inside of the 551? It would be interesting to see what else may have been modified.

Regards
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