Jump to content
bitfracture

Errors Reading 1050 Disk Drive

Recommended Posts

Hello AtariAge community, I am hoping some of you could provide some insight into a problem I am having with my Atari 1050 floppy disk drive. For years the drive has worked seamlessly with my Atari 800 XL... but when I pulled it out and started it up just recently, I only got one successful boot out of it, and it hasn't worked since. I know this is rather open-ended, so I will provide some information on what I have tried so far.

 

I cleaned the reader heads, so no problem there. I heard that the read arm is supposed to travel the full length of the read track upon initialization of the device. Whether this is correct or not, my device does not do this. It travels maybe a fourth of the way and then back.

I tried the following program which I grabbed off of another forum:

5 GOSUB 1000
10 POKE 769,1
20 POKE 770,33
30 POKE 772,0:POKE 773,64
40 Z=USR(1536,58451)
50 ? "FORMAT STATUS ";Z
60 FOR R=1 TO 30 : POKE 778,R : POKE 779,0
70 POKE 772,0:POKE 773,64
80 POKE 770,82
90 Z=USR(1536,58451)
100 ? "READ SECTOR ";R;" STATUS ";Z
190 NEXT R
999 END
1000 A=1536:TRAP 1030
1010 DATA 104,104,133,213,104,133,212,32,17,6,132,212,169,0,133,213,96,108,212,0,-1
1020 READ D:POKE A,D:A=A+1:GOTO 1020
1030 RETURN

This program formats the disk, then gives a status number in return. It then checks individual sectors from 1 to 30, and gives the read status. During the formatting process, the arm moved the full length of the floppy disk and appeared to be doing exactly what it should, however during the read phase, the disk drive reader arm did not move at all until the 21st sector or so, where it began to twitch with each sector read. Still every transaction with the drive returned a status of 144, which is a "Device Done Error" according to this website: http://page6.org/archive/issue_22/page_10.htm.

 

"This error occurs when you have issued a valid command to the peripheral but the device is unable to carry it out" the page says.

 

I have received a request from a friend to replace all electrolytic capacitors, because even if they do not burst, they are prone to drying up over time. Does anyone want to support or deny that statement? If so, is it possible that the caps dragged other more important (and harder to diagnose) components with them?

 

Sorry for the load of information, but any help on where to start with this is greatly appreciated.

Thanks,

 

BitFracture

Share this post


Link to post
Share on other sites

I always start by lubricating the bearings and then checking disk rpms

after a long time in storage... sometime the drives get sticky spindles after sitting.... you can use any of the rpm software out there or use the pattern that appears on the underside of the mech when adjusting speed just make sure you use the proper pattern 50 hz or 60 hz.

I think sparta has an rpm command as does disk doctort etc etc.

This fixed about 5 of my drives... too slow no go too fast and some copyrighted games did not work. I think it was 288 rpm

You can allways pull the mech and remove the shields and reseat the chips.

Sounds like its moving out and back like it should so track zero should be fine.

The caps may indeed be going bad it happens....

No it does not need to sweep all the way in and back out it just moves part way in and back to make sure it is finding track zero

Edited by _The Doctor__

Share this post


Link to post
Share on other sites

On powerup, the head doesn't move the entire duration, it's actually something like half or less.

Part of the reasoning is just a track zero reseek.

 

Strange that a disk would format successfully but then give read errors immediately - the format process works by seek track zero, then lay out 40 tracks worth of sectors then read them back from Track 39 to 0. In the event of an error you should have a status reflecting it.

 

Enhanced density disk is 26 sectors/track, single is 18 sectors.

 

Hard to say what's going wrong with your drive, could be mechanical, could be electrical and could be bit of both as a result of not receiving the proper voltages.

 

You can get the Field Service Manual and Sam's Computer Facts books for the 1050 online - they should list the procedure for checking voltages

Share this post


Link to post
Share on other sites

Thank you for the replies. I am going to try to obtain a light tester for RPMs so I can at least see whether that's a problem or not, but it might be a while before I get back with results, just due to the inconvenience of it. I will get back with results as soon as I can.

I am wondering though, what would I do to adjust the RPM if it is off? There isn't some variable resistor down there, is there? I don't know how one would correct the speed of a step motor without changing the clock circuit... The field manual refers to that section as the PIA. I really need something I can adjust on the fly while running the RPM test to get it just right. Where do I start?

 

"The DC motor includes an internal Tachometer, whose output is monitored in the tach feedback circuit. The Tach Feedback circuit senses the changed in current and maintains a constant motor speed. " - 1050 Field Service Manual

 

If that's so, I would think the drive would be auto-adjusting...

Edited by bitfracture

Share this post


Link to post
Share on other sites

Looks like Atari Age was down today... and some posts have dissappeared, maybe their drive needs adjustment too!

 

quick scan of the forums and we find some links for you, sometimes reading what someone else went thru is helpful and you find other issues to fix so you get it all done all at once.

 

http://atariage.com/forums/topic/190142-atari-1050-disk-drive-stopped-working-help/?hl=%2B1050+%2Brpm+%2Badjustment+%2Bpot&do=findComment&comment=2405724

 

a little light reading, do down to don't dump your drive.

http://www.atarimania.com/mags/pdf/page-6-issue-75.pdf

 

if you want to go on a real trip

http://atariage.com/forums/topic/167472-atari-1050-turbo-module-test-fail/?hl=%2B1050+%2Brpm+%2Badjustment+%2Bpot&do=findComment&comment=2351073

Edited by _The Doctor__

Share this post


Link to post
Share on other sites

quick answer load rpm tester, locate pot usually blue raised rectangle near heat sink and transistors use a tiny tiny flat blade screw driver to adjust the pot, timing is a big deal on the drives and it looks like 288 is the correct rpm.

Share this post


Link to post
Share on other sites

quick answer load rpm tester, locate pot usually blue raised rectangle near heat sink and transistors use a tiny tiny flat blade screw driver to adjust the pot, timing is a big deal on the drives and it looks like 288 is the correct rpm.

 

I am always so worried to mess with those things, haha. I don't see a normal pot on this thing. I do see that orange box (VR2). Is that a tiny screw sticking out of the top? This thing feels like it is going to break off if I wiggle it any more... I don't know how I will get the glue off of the screw without ripping the whole dang component off the pcb.

 

EDIT: Got it clear of the glue! That stuff sucks... anyway, I will see what I have in my shop for timing, but it's not likely I have what I need. I will have to bring it into the school around here and borrow their equipment. It just might take me a week.

Edited by bitfracture

Share this post


Link to post
Share on other sites

Slightly unrelated but important question: Why is the heat-sink hot enough to burn me after 5 minutes? I can always modify it, there's lots of case space, but I am wondering if it is supposed to get this hot in the first place :/

Share this post


Link to post
Share on other sites

Hot heat sinks (and rectifiers) normally means bad capacitors.

 

You cannot set the speed with the decal on the spindle (under a florescent light). That will set it to 300RPM instead of 288. You can get close by setting it a little slower on the decal - like 12RPM CCW.

 

Bob

Share this post


Link to post
Share on other sites

Hot heat sinks (and rectifiers) normally means bad capacitors.

 

You cannot set the speed with the decal on the spindle (under a florescent light). That will set it to 300RPM instead of 288. You can get close by setting it a little slower on the decal - like 12RPM CCW.

 

Bob

 

So, this is going to be more of a guess-and-check game than I thought...

As for the caps, would that be the large ones near the power input? Because replacing those darned things might take a long while waiting for them to arrive and getting them switched out.

What I have been told is that dry caps will register as good on a cap test, but will flunk out under a load. I need a sure way to test them before just replacing all 10 to 15 some-odd caps on this board.

 

In order to get a sure speed, can't I just set my speed tester to the right frequency and use the decals on the motor? If I have to use a different frequency I can, just as long as I know what it needs to be.

Edited by bitfracture

Share this post


Link to post
Share on other sites

 

I am always so worried to mess with those things, haha. I don't see a normal pot on this thing. I do see that orange box (VR2). Is that a tiny screw sticking out of the top? This thing feels like it is going to break off if I wiggle it any more... I don't know how I will get the glue off of the screw without ripping the whole dang component off the pcb.

 

EDIT: Got it clear of the glue! That stuff sucks... anyway, I will see what I have in my shop for timing, but it's not likely I have what I need. I will have to bring it into the school around here and borrow their equipment. It just might take me a week.

SpartaDOS 3.2d or SpX has a 'RPM.COM' you can use.

 

 

SpartaDOS 3.x or SpX can run a RPM test that you could use. Although, I'd try replacing U1 first, even before replacing the large caps. I think it is risky messing with the RPM pot.

Just run RPM.COM and see if speed is off much from 288.

RPM.zip

Edited by russg

Share this post


Link to post
Share on other sites

I can't boot anything... at all... because this darned drive is toast right now. Also, I don't have SpartaDOS or any way to format a disk with it.

 

Also I took some DC voltages at the regs, I figured if the power input was screwy, that would be a good place to find out. Can anyone verify if these look healthy? Yes, they do drop a little when the motors are running.

 

Voltage%20Regs.jpg

Edited by bitfracture

Share this post


Link to post
Share on other sites

Oh boy, now it's monumentally screwed. When I power it on, it spins, then stops, then spins, then stops... and so on. It did this once before, but stopped and went back to normal. I'm getting seriously frustrated. All I've done to this thing is try adjusting the potentiometer up and down. I'm sure it's way out of the correct time by now, but for things to just quit like this is really weird.

Share this post


Link to post
Share on other sites

make sure you have the connectors firmly seated going to the mech, and those capacitor sometimes come loose or have hair line cracks you might resolder them. They could be bad. can't hurt to try though. If you have had this apart before you might have a connector in the wrong way or place. a double check might not hurt.

Share this post


Link to post
Share on other sites

the caps sometimes can be removed reformed and re-installed, I have done this twice

 

http://www.vcomp.co.uk/tech_tips/reform_caps/reform_caps.htm

 

google for you most comfortable method and post.

 

you can also make the heat sync and power consumption less just search the forum for 1050 goes green or goodle than phrase. The cooler running drive will have a much longer life! you can do the same an xf551

Share this post


Link to post
Share on other sites

@ BOB1200XL, your right.. I had dos on cart so I got it close using 60 with a cheap test light and dialed them in using rpm test program, other times I had booted from different drive. only thrice since the 1980's did I ever have to physically re-align one of these drives, it has alway been speed, cap, diodes, track zero and once a write protect switch.

 

I only ever lost one drive and that was due to motor failure....

Share this post


Link to post
Share on other sites

@ BOB1200XL, your right.. I had dos on cart so I got it close using 60 with a cheap test light and dialed them in using rpm test program, other times I had booted from different drive. only thrice since the 1980's did I ever have to physically re-align one of these drives, it has always been speed, cap, diodes, track zero and once a write protect switch.

 

I only ever lost one drive and that was due to motor failure....

 

Do you think it is worth it for me to purchase dos on a cart? If so, which version?

Also to follow up what I previously said, the drive fails after it gets hot and starts to cool down. If I leave it for a long time it fires back up good as new (Well, kinda, anyway... because it still won't read a disk). I will get out a magnifying glass tomorrow and look for cracked solder points. With good luck I may just get myself a strobe to test RPM's with, but I will need some guidance. I don't have a single element of software for my 800XL that isn't on a floppy.

Edited by bitfracture

Share this post


Link to post
Share on other sites

SpartaDos to flashcart is probably the way to go.

 

Short programs like the one up top you listed can do format/sector read tests etc though.

Share this post


Link to post
Share on other sites

okay once you are sure of solder joints good, voltages correct, all chips are seated properly (under shielding), mech wires plugged in correctly! - they don't all plug the same orientation- and remember there is one with delicate wires under the drive mech going to the head. let it come up to temperature like you said... You can try an aero duster to find thermal components. you simply cool or freeze hot chips one at a time till you find one that is failing.

 

Yes a sparta cart, or flash cart with either spart or mydos works fine.

 

sometimes the caps come back with use or forming, sometimes they are shot. no choice but to replace em. Really wish you had a second mech to swap with.... check out the local thrift shops they usually get em and sell em cheap. Serious... my last drive cost me $1.42 with tax...

Share this post


Link to post
Share on other sites

Really wish you had a second mech to swap with.... check out the local thrift shops they usually get em and sell em cheap. Serious... my last drive cost me $1.42 with tax...

 

I am trying to do just that. I have been watching eBay and looking through thrift shops. I want to get another very badly. I've also been on the lookout for tape drives, those things are neat.

On the topic of the cooling process to locate dead chips, how would that work? Are we just waiting for the device to trip up when we cool a particular component? It seems to me that such a process would only highlight broken solder leads (If not break more of them)

Share this post


Link to post
Share on other sites

okay once you are sure of solder joints good, voltages correct,

 

I don't know the voltages I should look for because the service manual isn't much of a help in that area. I posted the voltages at the regulators above but I didn't get much of a response to that. I need a manual with voltages laid out. I can check the IC's by their datasheets, but that's about it.

Share this post


Link to post
Share on other sites

If the regulators are too hot you are drawing too much current, either through the capacitors or some other failed component. Once the regulator hits its maximum temperature, it shuts down until it cools off. This is the way it is designed.

 

Your voltages look OK.

 

You can just use a florescent light to set the RPM close - shine it on the decal and set the pattern (with VR2) to run CCW, slowly. Speed doesn't matter so much, really. You have to fix your power problem, first. Yes, the big caps are the most likely - and, they are a PITA, but that is where I would start. Just change them..

 

Bob

Share this post


Link to post
Share on other sites

 

I don't know the voltages I should look for because the service manual isn't much of a help in that area. I posted the voltages at the regulators above but I didn't get much of a response to that. I need a manual with voltages laid out. I can check the IC's by their datasheets, but that's about it.

Get a SIO2PC or APE cable and APE or ASPEQT software. Then you can run any DOS you want, except cart DOSes. Then you can test your 1050 with a sector reader like RW13.COM

RW13.zip

Share this post


Link to post
Share on other sites

Get a SIO2PC or APE cable and APE or ASPEQT software. Then you can run any DOS you want, except cart DOSes. Then you can test your 1050 with a sector reader like RW13.COM

 

I am wanting to get that, and I am watching one on eBay, but those things are so overpriced, it's a killer...

Am I able to daisy chain the SIO2PC out of the SIO port on the 1050? If my OS is on the thing I would think that would be important, but I heard something about the SIO2PC using all IO channels for virtual drives and I don't know if that would conflict with the physical drive, being on D1 currently.

I actually did get a strobe light today, I can fine tune it too, it's excellent. I just need to know exactly what to tune it to. It gives me a digital readout on the top of the strobe, I -think- that it displays rotations per minute. I could be wrong. What do y'all think? It's this expensive thing: http://www.grainger.com/product/5AY35?gclid=CK7rkPiBlbwCFat7QgodSkwAQg&cm_mmc=PPC:GooglePLA-_-Test%2520Instruments-_-Nonelectrical%2520Properties%2520Testing-_-5AY35&ci_src=17588969&ci_sku=5AY35&ef_id=UYrAoQAAALhAZ3tT:20140123191932:s

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...