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foxmulder900

Atari 1050 Disk Drive Power-Up Failure

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I'm trying to fire-up a 1050 that has not been used in a very long time, unfortunately its failing the Power Up Test as described on page 22 here: http://www.jsobola.atari8.info/dereatari/literatdere/1050fsm.pdf

I found this very similar thread that did not come to a resolution:


But I was still wondering if anyone has had any luck troubleshooting the 6 checks listed in that document as causes for the power up test failure:
 

  1. Input/Output Device:
    The 6532 device is initialized and verified. Upon incorrect comparison, the processor will flag ERROR.
  2. Disk Controller Device:
    The 2793 or 2797 device is tested for ass to the track, and sector registers, followed by an internal functional test. Upon error, the processor will flag ERROR.
  3. ROM Checksum:
    The processor verifies PROM validity by performing a checksum on it. Upon error, the processor will flag ERROR and discontinue testing.
  4. RAM Check:
    Unique values are written to each RAM location, and then each location is read to verify It contains the correct value. Upon error, the processor will flag ERROR and discontinue testing.
  5. Error Flag Stop:
    Upon any ERROR flag being set, the processor will discontinue testing and place the unit in a hard failure state (2-second cycle off/on of spindle motor).
  6. Restore Check:
    Track 0 is sought by stepping the head away from spindle until track 0 sensor is detected and motor phase is 1. Upon stepping more than 50 tracks without finding the track 0 sensor, the unit will fail and enter the hard failure state.

 

Additionally, it may be relevant that my drive has what I understand to be the later revision using the World Storage Technology mechanism.

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Maybe some photo's of the internals, showing the mechanism.

 

When you say it fails the test on Page 22, at what point does it fail ?

 

Have you checked for the correct power supply voltages ?

 

Have you checked if all IC's are in their sockets correctly, maybe re-seat.

 

Also 1050's can have capacitor problems as they age, it's quite common practice to replace all the electrolytic capacitors.

 

 

 

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Remove all socketed ICs and check there is no tarnishing on the pins and sockets. If there is clean them. If in doubt clean them.  

If you have a can of compressed air, blow through the sockets to clear any debris. Reseat all the ICs and test.

 

Regards

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https://atariage.com/forums/topic/307471-two-dead-1050s/?do=findComment&comment=4554280

I just fixed my 1050 with the same symptoms two days ago

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Hi, do you have a 1050 diagnostic disk you can run? It could really help spotting where the issue comes from.

Also, having a good 1050 to swap chips and drive to isolate is really helpful. 

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Thanks all!

  I'm not sure how to tell which step it is failing on unfortunately but I'm pretty sure I have the correct power supply (see photos below). I also went ahead and pulled all the chips, cleaned things up with some contact cleaner and compressed air, then re-seated. But no luck. I don't have a diagnostic disk or a spare drive, but I'll definitely keep an eye out for some :) I do have a set of replacement capacitors in hand though, so I'll try replacing those in the next few days!

If all else fails, I may consider your idea @archeocomp, that seemed like some good detective work.

Also, the back of my board has a few wires soldered directly onto it. Has someone already messed with this board? Or is that a late revision factory modification or something?

IMG_4399.jpg

IMG_4396.jpg

IMG_4395.jpg

IMG_4394.jpg

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Posted (edited)

How about some good old fashioned DMM work, with your multi meter, check the power at the voltage regulator then at the diodes and then after the capacitors.

once your sure you have good clean power then we can move forward.

what happens with the drive head when a disk is inserted and you turn the drive on, then off after a moment, then on again after a moment.. and so on.

 

Edited by _The Doctor__

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Posted (edited)
23 hours ago, _The Doctor__ said:

How about some good old fashioned DMM work, with your multi meter, check the power at the voltage regulator then at the diodes and then after the capacitors.

once your sure you have good clean power then we can move forward.

I am quite the amateur with these things, so forgive me for anything that doesn't make sense. But I got the following readings:
 ~9v in
 ~12v in & 5v out at Q7
 ~22v in & ~12v out at Q8
 ~12v in & ~12v out at Q6

My understanding is that those first 3 are as expected, but I'm not sure the purpose of the Q6 voltage regulator, so I'm not sure what is expected there. But here is where my understanding gets fuzzier, I assume the diodes you are speaking of are CR15 and CR16? But I'm not sure what voltages are expected there (or how to measure them for that matter).

Also, there is no difference whether or not a disk is inserted, the cycle continues and the head never moves.

Edited by foxmulder900
submitted too soon

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Posted (edited)

when you say the head never moves, it never moves no matter what position you've put in while power is off, and when your watching at power on it never moves?

the fsm indicates what voltages should be present where including test points...

is this the only WST drive in your possession?

Edited by _The Doctor__

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On 6/10/2020 at 12:17 AM, _The Doctor__ said:

when you say the head never moves, it never moves no matter what position you've put in while power is off, and when your watching at power on it never moves?

the fsm indicates what voltages should be present where including test points...

is this the only WST drive in your possession?

Right, no movement no matter what.

I see the specific voltages in the service manual now, I didn't realize there were all these test points built in! I started taking some readings, and the one that stuck out was TP14. The manual says I should be getting 12v, but I was only seeing around 5. The manual suggests replacing "CR15 and CR16, or C71" when TP14 doesn't read 12. I have a replacement for C71 in hand so I'll try that first.

Although (and sorry for the noob question) is it possible for me to blow an AC adapter by using my multimeter at the solder points on the power jack? I got a 9v reading there a few times, but the two original power supplies I have died during my troubleshooting. I thought the first one died just due to age, but after the second I'm not so sure. (I have a new one on the way, but I want to make sure it doesn't blow as well)

Lastly, this is the only drive in my possession currently, but I may be getting a second shortly (not sure if its Tandon or WST yet).

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Those diodes and cap are common failure items. Make sure to mount replacement diodes with long legs to allow airflow for cooling.

 

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Quick update: I spent some time with the service manual and gained a better understanding of how to properly test the voltages. I was definitely doing it wrong before, but I got a new ac adapter and everything now looks fine as far as the power supply goes. Getting +5v at TP13 and +12 at TP14. I also got ahold of a second drive! Unfortunately its not a WST like my original and it's not working either (appears to be in rougher shape). However, I swapped the FDC and got past the power-up test! The drive motor spins, and the head moves back and forth once on powerup. When I put in a disk and start my 800xl, the disk it spins, but I get the continuous BOOT ERROR. So next I found this super handy post about adjusting the drive speed:


My frequency at TP10 was definitely off (~155Khz) I adjusted the pot to the recommended ~125Khz, but still getting the boot error. (I do not have an oscilloscope to test the other two values unfortunately, if there is a way to test these with just a multi-meter, please let me know :) )

I still haven't replaced any caps or diodes since I haven't really been able to identify one as the problem specifically, but I cleaned the head with isopropyl and confirmed the pressure pad is present. However, since I only have one floppy, it feels like it's time to rule out a bad disk.  I went ahead and ordered some various others offline that claim to be tested. So we'll see how that goes!

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You will have to have a way to write to the disk drive...

this normally requires the computer to boot a DOS disk and then you go from there...

 

common mistakes are having more than one SIO device on the same ID... causing the Atari to poll both and conflict resulting in error..

 

If you have a sio2whatever device, the sio2whatever must not have any image in the same slot as the physical drives ID.

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3 hours ago, foxmulder900 said:

However, I swapped the FDC and got past the power-up test!

The drive may need re-calibrating after changing the FDC.

 

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You all have been unbelievably helpful, and it's been a lot of fun troubleshooting this thing. Today I have some good news. I got a fresh stack of disks and a few of them booted!

Last night I spent some time playing Lapis Philosophorum and Alternate Reality The Dungeon! (and a little bit of Strip Poker haha)

 


IMG_4457.thumb.jpg.fb8fa915baac2fb5e82b7b8a4e94828f.jpg



However they were all claimed to be "tested", yet many of them still cause a boot error. Is it possible for some disks to be more tolerant to rotational speed variances than others?  Since (as @archeocomp mentioned) I only adjusted the clock speed, and @_The Doctor__ recommends adjusting rotational speed as well, I'm wondering if I could get more of these disks to play.

 

 

 

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Do you have a standard DOS 2.5 (or MyDOS or SpartaDOS) disk?  Some of the disks may not be "boot disks".  Load DOS first and then try getting a directory.

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8 minutes ago, Stephen said:

Do you have a standard DOS 2.5 (or MyDOS or SpartaDOS) disk?  Some of the disks may not be "boot disks".  Load DOS first and then try getting a directory.

I do not, but I will see what I can do to get ahold of one :) Is either considered superior?  I did just realize I have a "Translator" disk though, if that was in this stack I bet some of them need it.

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Yes, if you found a translator disk, chances are some titles need it.

Stephen is correct, many people didn't make all disks boot disks, they used a boot disk and the rest of the collection might only have games or software on them giving more space for those titles as the room from the dos and dup area could then be used for those titles instead.

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Look into Ultimate 1M to get SDX built in, 1M RAM, and more.

SIDE2 or the new 3 for [fast] hard disk.\

FujiNet is awesome.

These are must have peripherals.

 

 

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