Broken 1050 disk drive?

[Chad Beeder]

I picked up an Atari 1050 at a thrift shop yesterday, hoping it would
work. Well, it doesn't quite seem to, so I have a few questions.

When I turn it on the power light comes on, but then it just sits there.
If the power is on, however, and I toggle it off and then back on again
quickly, the motor that spins the disk starts trying to run. I say
"trying" because it just turns very slowly and mostly just makes a
grinding noise.

Some questions:

I've never owned an Atari disk drive before; is it normal for it to only
start spinning the disk if the power is toggled off and back on quickly?
This doesn't make sense to me, but it seems strange that this would be the
problem.

Apparently someone else had the thing open before I did, and it looked
like they had some of the connections from the electronics to the drive
wrong. I looked at them, and they were labeled with numbers like "J10",
"J12", etc., and had a small number "1" printed on the bottom. Apparently
desgnating pin #1. There were apparent matches to these numbers printed
on the circuit board that they plugged into, so I plugged 'em the way they
seemed to match. Did I do this correctly?

What are the settings for the "drive select" switches near the back of the
drive?

It didn't come with power supply or SIO cable, so I'm using some from a
1010 tape drive I have. This should work, shouldn't it?

I don't have any disks with DOS on them; is this required?

Does anyone have another broken 1050 (preferably in the Seattle area so I
don't have to pay a lot of shipping) that I could take off their hands in
hopes of making a working disk drive from the two?

Thanks in advance for your help.
--
_________
/___ _/ __ syz...@eskimo.com (Chad Beeder)
//_//_ /_/ /_/ /_/ "And everything under the sun is in tune,
_____/__/_____/___/___/ but the sun is eclipsed by the moon."

[Jeff Popp]

Would the person who posted this message please describe the problem again?

[James Hague]

On a related note, what's the best source of information for
learning how to fix 1050s? (At least simple problems.) Have
any tips been collected in one place? How about the Sams
books? (Suggestion: This would be a great idea for an AC
article.)

--
James Hague
exu...@exu.ericsson.se

[Rick Cortese]

exu...@exu.ericsson.se (James Hague) writes:

I've fix a dozen or so 1050's now & will ACK other people may have had
other problems, but what I've found: 75% of the problems are with the 12V
power supply [cr15, cr16]. 15% have the controller chip go which makes it
cheaper to buy a used drive then try to repair them. The other thing that
goes is the track zero sensor. I've got the SAMs 1050 repair manual & it
really isn't that great unless you have an scope. If I recall corectly,
all motor spin/fail to spin problems ('cept for controller) were 12V
supply problems. When you have the track zero sensor go out, you just
take the cover off the drive. What happens is the head gets brought to
track zero & you may or may not get a good starting read. The next time
it looks for track zero a 'bad sensor' tells it the head's on track zero
already so after each try, the head advances across the disk.

--
Rick Cortese
internet: rico...@TheRat.Kludge.COM uucp: ...!apple!therat!ricortes