Help with broken Atari 1050 drive

[jrentschler]

Hello all,

 

I recently purchased an Atari 800 system at a yard sale. It is my understanding that the system hadn't been powered on and used since the late 1980s. After getting it all home, I proceeded to test out the individual components. The computer works, but the 1050 for only a split second had any power going to it (the red LED was active, but no motor activity). Now there is absolutely no life apparantly left in the drive. I have no proof to confirm my suspicions, but I believe that the mechanical components to the drive are still likely in working order. Can someone tell me where to begin with attempting to revive this drive by replacing parts in the power circuitry? I imagine some capacitors or FETs have gone? Bad fuse? Cold solder joints? I haven't yet had the courage to disassemble the drive for fear of what creepy-crawlies might be living in there. Your help will be greatly appreciated.

Edited February 12, 2008 by jrentschler

[jhillestad]

You may just need to reseat the firmware.

 

Look at the instructions for the Happy install and open the 1050 up confirming the connectors.

 

I would also open the cage as if you were installing a Happy chip and push down on all seated chips that reside in the rf cage.

 

http://www.atarimax.com/myide/documentatio...ppy_install.pdf

[+bob1200xl]

The 1050 uses a voltage doubler to make 12 volts so the circuit looks a little strange. The rectifiers and filter capacitors go bad, which may blow the fuse in the 9vac power transformer. You have to cut the case open to change the fuse. You need to fix the drive, though, or you'll just blow the fuse again. You can meter the parts one at a time, in-circuit, to see who is shorted. The power rectifiers always look nasty and burnt - doesn't mean they're bad. Is it worth fixing? You should get a schematic. I think I saw one somewhere online. Anybody?

 

Bob

 

 

Hello all,

 

I recently purchased an Atari 800 system at a yard sale. It is my understanding that the system hadn't been powered on and used since the late 1980s. After getting it all home, I proceeded to test out the individual components. The computer works, but the 1050 for only a split second had any power going to it (the red LED was active, but no motor activity). Now there is absolutely no life apparantly left in the drive. I have no proof to confirm my suspicions, but I believe that the mechanical components to the drive are still likely in working order. Can someone tell me where to begin with attempting to revive this drive by replacing parts in the power circuitry? I imagine some capacitors or FETs have gone? Bad fuse? Cold solder joints? I haven't yet had the courage to disassemble the drive for fear of what creepy-crawlies might be living in there. Your help will be greatly appreciated.

[jrentschler]

Thank you all for your replies.

 

I know for certain that it is not the transformer, as it works with another 1050 and a 400.

[JR>]

I think I saw one somewhere online. Anybody?

 

http://nuxx.net/gallery/v/computers/atari8...ematic.png.html

[puppetmark]

Make sure you are gettign 5 nd 12 volts from the internal power supply. The 1050s have linear power supplies and the regulators and Caps are prone to fail. The 1050 has test points for this and all you need is a multimeter and the schematic.

 

If the power supply checks out, then things get tougher but start with this.

[Urchlay]

Have a look at this thread, it may be useful to you: http://www.atariage.com/forums/index.php?showtopic=120316

[1050]

What follows is a compendium of 1050 symptoms and solutions from the "other" forum. Author's name immediately follows the link to the message so the proper people get credited.

 

http://groups.google.com/group/comp.sys.at...bf97b59fb9dd62c

Bob Woolley

 

When you power on a 1050, it checks the operation of the 6532 chip. If it fails, the select light just blinks (it is checking over and over...). Once it thinks that the main chips are OK, the drive seeks (steps) to track 0 by moving the head back until the track 0 sensor is active. If the track 0 sensor does not see the flag after 40 or 50 steps, the 1050 dies. If your drive moves the head, it probably passed the logic tests. If the head moves but the drive will not run, it is probably the track 0 sensor. It is a little, black, U-shaped gadget mounted at the back of the head carriage. They go bad all the time.

 

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http://groups.google.com/group/comp.sys.at...6bc9830b97f9514

Rick Cortese

 

Dun...@aol.commercial wrote:

> I have a drive here that doesn't do anything when switched on. The

> power LED lights and that's it. Is there anything that is particularly

> likely to have failed or could it be almost anything?

> Thanks everyone!

 

The 12V supply is the most frequent fault. Atari used a voltage doubler

and the diodes in the middle of the BIG capacitors come loose from

thermal shock/over heating.

 

There are a few other things that are likely. The 1050 should have the

drive busy light come on everytime you close the door latch.

 

What you should try is having the drive on, a disk in it, and hooked up

to the computer. Turn on the computer and see if you get an abnormal

boot noise like a screech. If it gives an abnormal noise then at least

the computer and drive are trying to talk to each other. If it doesn't

make a difference with or w/o a drive then you have something seriously

wrong like a bad disk controller chip.

 

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http://groups.google.com/group/comp.sys.at...75e4cf5698883e7

Rick Cortese

 

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

> 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

 

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.

 

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http://groups.google.com/group/comp.sys.at...2ce919a0f73c827

Ron Hamilton

 

> Rick Cortese <

> Few more tests have to be done.

 

> Try booting the computer with the drive powered up and the drive powered

> off. If it makes the same noise in both cases, then it is probably a

> RIOT/PIA type chip, 6532 IIRC.

 

> If it makes a different noise in each case, it is probably the 12V power

> supply. The 12V supply can be confirmed to be out by inserting disks in a

> powered up drive. The activity light should go on when the door latch is

> closed.

 

> You may be able to just resolder the diodes on the back of the board

> between the large capacitors. They break loose from thermal cycling.

 

And sometimes, one fails requiring replacement. Check resistance across

individual diodes in both directions with a VOM. They should be high one way

and low the opposite and all 4 about the same. I replaced my odd one with an

IN 5400 from Radio Shack # 276-1141 and it is still ginning 18 months so

far.

 

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http://groups.google.com/group/comp.sys.at...10af1df19d695a3

Rick Cortese

 

> > With the drive cover off and a disk inserted, what happens to the head if

> > you repeatedly cycle the power?

 

> It moves forward in small increments until it reaches the end of its

> path and then keeps trying to move forward, but just rattles because it

> has run out of space.

 

Good news is I am 99.9% sure it is the track zero sensor. Bad news is they

are a bit hard to find and expensive when you do find them.

 

I remember when one went out on me I balked at paying the ~$13 B&C wanted. I

ended up carefully taking the sensor case apart and found it was just a flat

rectangular LED in the plastic. I just sanded a regular IR LED from Radio

Shack to fit in the plastic and glued the case back together. Yes, I am that

cheap.<grin>