Attempting to repair a 1050 Disk Drive-no activity light no motor/head spin

[_The Doctor__]

yep you need a formatted atari dos 2.0 or 2.5 disk to do complete testing... once the rpm is set correctly, you might find more out about what's what

 

making a disk on an unknown drive can be tricky, If you have a know good drive try this, then swap out the good drive for the unknown drive. If you don't have a know good drive, and you are fairly dialed in on rpm's then go for it with the unknown drive straight away.

 

1050 off

Boot DOS 2.x from an ATR on SIO2SD D1: slot

disconnect SIO2SD

turn on 1050 and insert a blank disk to format

choose option I to format a disk, while DOS 2.5 is P format a single density disk

then choose H to write DOS to disk and make it a boot-able disk.
make more than one (several) if possible, you will need a few for all tests, and keep one to the side for later use

Edited September 5, 2018 by _The Doctor__

[repetto74]

Hi Nezgar,

 

Thanks I do have a ATR copy of the DOS 2.5 :-). I will give this a try then and let you know.

[+Nezgar]

Formatting is actually a good usability test for a drive too. The drive and the disk itself have to be in decent condition to successfully complete, so watch for failures during the format process, and listen for timing irregularities in the stepping during format which can suggest when the drive is having difficulty even before a final error result.

[repetto74]

Hi Nazgar,

 

Thanks a lot things have moved . I have loaded DOS 2.5 and then formatted a DD blank disk + DOS and it went well (which is already a good thing). Running the diag test gives this now. Only one fail and RPM a little bit high.

 

 

[+Nezgar]

So your RPM's are a bit too slow. Maybe adjusting the RPM speed pot will help with the 1 failure. Carefully adjust the one circled in green with a small tipped flathead screwdriver while the test is running until it's within spec.

[repetto74]

Hi Nezgar,

 

Noted I will fine tune the RPM and let you know :-).

[+Nezgar]

Also try with the tester disk formatted in Single Density, not Double. (more commonly referred to as Dual or Enhanced density, since a non upgraded 1050 can't do true Double Density 256 byte sectors)

[repetto74]

Also try with the tester disk formatted in Single Density, not Double. (more commonly referred to as Dual or Enhanced density, since a non upgraded 1050 can't do true Double Density 256 byte sectors)

 

Is there an option in DOS 2.5 for that? P option will format SD I think.

[+Nezgar]

Yes, in DOS 2.5 it's option P. FORMAT SINGLE

[_The Doctor__]

rpm's were too FAST not slow... unless he's testing response time then response would be too slow... since I am on a phone I can't see it.

did he adjust rpm to 288?

 

2.0 I formats single (aka initialize single density disk)

 

2.5 I formats enhanced (aka initialize enhanced dual density disk)

P formats single (just like on 2.0)

 

this is a re cap explaining what I posted at the top of this page more fully!

Edited September 5, 2018 by _The Doctor__

[+Nezgar]

Atari's diagnostic software measures in milliseconds per revolution, and doesn't translate that to RPM. So in this case his measurement time is 2ms per rev longer than spec,

(210.1ms instead of target 208.3ms) so the drive is slower than 288rpm, but probably not by much.

[repetto74]

did he adjust rpm to 288?

 

No adjustment done yet. Speed is actually at 210 where it should be ideally at 208. This is the next thing to do. The blank disk I formatted was already a single with option P from DOS 2.5.

Edited September 5, 2018 by repetto74

[+Nezgar]

Ah. 210.1ms: 60/0.2101 = 285.58RPM

[_The Doctor__]

2.42 slow, a simple touch of the screw and it's all good, try more than one disk... and shoot for the average. you can go plus or minus a ms from target just fine.

 

adjust vr2

Edited September 5, 2018 by _The Doctor__

[_The Doctor__]

the 1050 diag disk is supposed to be the same density as the test disk If memory serves, here's the FSM

1050fsm.pdf

 

so go to troubleshooting and select speed test memory loop (1)

and adjust vr2

 

starting to think we should have a single thread dedicated to all the manuals so we can just include the link to them here on AtariAge

 

hmmm 10 min burn to make sure single density works and acts like it should to be compatible with the 810

 

2 hour burn in for dual density... after an hour if it ain't gonna happen... it ain't but hey 2 hours of torture why not... can't be too sure... let's nuke em from orbit

Edited September 5, 2018 by _The Doctor__

[repetto74]

Hi Guys,

 

So I have tuned the drive speed to a nice 208,1 ms but all test are ok except the Head Step/Settle which still fails. Rails are lubed and head is cleaned with IPA. If I want to boot the formatted diskette to DOS it will just read and load fine with no problem at all.

 

Considering this drive as working unless there is something more I can do to clear the failure.

[_The Doctor__]

make sure the drive rails are as clean as can be.. to thick a lube etc. can slow the head down...

exercise the drive a bit (full rail) seeks etc.. see if it improves, add a single drop of light machine oil at spindle bearing on stepper motor. and exercise.

 

if that doesn't do it swap know good mech, it it passes put old one back in and align.

 

most purchased disk or atari formatted disk are good enough to align with, but you can still purchase the actual alignment disks from the usual suspects...

 

use a wet dry single sided cleaning disk...

Edited September 6, 2018 by _The Doctor__

[repetto74]

I will try to clean again the r/w mech and lub the rails again + stepper motor. Keep you posted :-)

[+kheller2]

I will try to clean again the r/w mech and lub the rails again + stepper motor. Keep you posted :-)

 

The disk you are testing against... did you format that since adjusting the speed?

 

"Head Step & Settle Test

Figure 15. Running 1 Option (continued)

This test checks the capability of the drive to read a sector, step to the next track, and read another sector within a specified amount of time. A failure here would indicate a bad drive mechanism, or a defect in the read circuitry.

"

[repetto74]

The disk you are testing against... did you format that since adjusting the speed?

 

Was formatted once before running the diag test and used a couple of time already. The disk will boot also into DOS.

[+Nezgar]

Was formatted once before running the diag test and used a couple of time already. The disk will boot also into DOS.

 

I agree with kheller2, formatting the testing disk again now that you have adjusted the RPM is a good idea. Because the disk was formatted at too slow RPM, the timings of the sector layout will be off, and its plausible it's enough to fail that test.

[repetto74]

I agree with kheller2, formatting the testing disk again now that you have adjusted the RPM is a good idea. Because the disk was formatted at too slow RPM, the timings of the sector layout will be off, and its plausible it's enough to fail that test.

 

Sounds good Nezgar :-). I will also format the disk again and try.

[+Roydea6]

Hi Guys,

 

So I have tuned the drive speed to a nice 208,1 ms but all test are ok except the Head Step/Settle which still fails. Rails are lubed and head is cleaned with IPA. If I want to boot the formatted diskette to DOS it will just read and load fine with no problem at all.

 

Considering this drive as working unless there is something more I can do to clear the failure.

is the nice 208.1 ms a typo because it should be 288-292 rpm in my documents ..

[+Nezgar]

is the nice 208.1 ms a typo because it should be 288-292 rpm in my documents ..

 

208.1ms per revolution = 288.32 RPM (60/0.2081)

[_The Doctor__]

Leave the rails dry... as the head slides now have more than enough lube...

re format your disk and exercise the drive.

then run the tests again with the newly reformatted disk,

that also should include re making the diagnostic disk into a real disk....

 

The fellows are correct, a disk formatted at incorrect speeds can cause the reading to be off, this is one of the reasons we use actual alignment disks, or known good disk created on known good drives.

 

If the drive is formatting a never before formatted disks in single and dual density, and then reads as well as writes them, you are probably going to be ok, but you are currently aligned and adjusted to yourself. It's possible the mech is spot on as most are, but you really could use a company created disk, or pre formatted disk to make sure it's all as it should be. We also used to adjust speed via the spindle pattern and strobe present on some drives.

 

If you have and Atari friend borrow some actual purchased game disks and Atari labeled pre formatted disks or you might find something cheap on ebay or have someone send you something you can use...