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80sAtariboy

Atari 810 Disk Drive Problem - Help and Advice needed

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Hi All

I need your collective knowledge please. I purchase an 810 off ebay and the seller was a bit cagy and non responsive to questions so I knew what I was up for. I took a chance on it and purchased it anyway. I got it today, plugged it in and turned it on. The drive busy and power light come on, the drive spins for a few secs and then stops with busy light off. Connecting it to the 800 computer and start up - nothing happens. So I took the lid off and basically the head assembly just sits there - it jerks a little on start up as if it wants to move. 

 

Any advice on how to fix? Is it the stepper motor? or some logic chip? The computer doesn't seem to acknowledge the 810 is connected. I connect other peripherals to the SIO port and it works so its not the 800 computer. 

 

Is this drive fixable - I love the design and want to give it another lease of life. It is the MPI drive mechanism.

 

Thanks for any advice. 

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Do you get the "BOOT ERROR" messages when you try to boot the 800 with the drive attached.

 

The drive has to be powered on and connected before you turn the 800 on.

 

If you get the "BOOT ERROR" then the 800 is seeing the 810.

You will need a DOS bootable disk in the drive for it to boot correctly.

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Can you post pics of the insides? There's a few "generations" of 810's - the oldest components being the most unreliable....

 

The drive should normally seek the head all the way to track 39 on powerup, and then back to track 0 after 5 seconds or so when the spinning also stops...

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Just now, Nezgar said:

Can you post pics of the insides? There's a few "generations" of 810's - the oldest components being the most unreliable....

 

The drive should normally seek the head all the way to track 39 on powerup, and then back to track 0 after 5 seconds or so when the spinning also stops...

the head mechanism on rails doesn't move at all. Just a spin of the circular spindle and then tops on start up. I suspect the stepper motor is dead or ceased. There is a little jerk on initial power up as if the head wants to move on start up. 

 

Not sure if it is a logic chip or side board issue?

810_2.jpg

810_1.jpg

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Could be the track zero sensor, not got an 810, but I had a 1050 that the head did just that, I confirmed the motor

was ok by moving the head out manually while the drive was turned off, when powered back on the head ran back

to the zero position, at least proving the head motor and mechanism was ok.

 

Replaced the sensor and all was fine.

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Well, that's definitely the "earliest" 810.... It's missing all of the enhancements Atari incrementally released for the 810 during it's production. It has the old power board, no top analog board, and probably no data separator daughterboard and a Rev B ROM...  From my experience even in a "working" drive without those upgrades it will be temperamental.. The slightest nudge of the RPM trimpot on the power board will throw off the speed by +/- 10RPM...  And the power board is insufficient to power up if you add a data separator to the side-board too..

 

Anyhow - you may have your work cut out if you don't have another 810 to swap parts from. Best electronics sells all the components for the "Grass valley upgrade kit" - but you could probably buy a few used 810's for that price...

 

With the drive off, can you manually slide the head transport forward back, or is it seized?

 

14 hours ago, TGB1718 said:

Could be the track zero sensor

 

The 810 has no track 0 sensor.... :)  But moving the head to the middle and powering up might be a good test... Normally if an 810 has issues reading, the firmware will smash the head backwards and make a grinding like an Apple Disk II to try to realign the head before retrying....  if you always power off the 810 after it has spun down and returned to track 0, it should "normally" never do this.... But it got quite a reputation on copy protected disks with intentional bad sectors invoking that behaviour, etc. There were ads for patched ROM's that would minimize it... ie CSS's "Silencer"...

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Slightly jerking and then stopping makes me think it might be a power issue. I have no experience with the 810, but are there any 7805/7812 regulators on the PCB? If so, check those with a multimeter.

Also check for bulging caps. Especially the bigger ones.

 

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7 minutes ago, ivop said:

are there any 7805/7812 regulators on the PCB?

The upgraded power board uses a 7805/7812, the original uses a power transistor (Q113) and a voltage regulator (A108) - not sure at the moment. The 7805/7812 in the later rev power board are in the places of J104 and J105 on this board...

 

The Rev 1 service manual would be what applies to @80sAtariboy's drive. ie (Page 6-13 and Appendix D for the rear board)

http://www.atarimania.com/documents/Atari_810_Disk_Drive_Field_Service_Manual_Rev_1.pdf

 

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Were there any final results to this post? I agree with Nezgar; it seems to be missing the analog daughter board that sits like a bridge over the drive rail section that was a hallmark of the later drives. It can be 'upgraded' with the grass valley kit or...you could just get it going and enjoy the very early 810 'vibe' of using older tech and living with its quirks.

 

If it gives a bit of a kick at startup and then has trouble I would also suspect power. So...what wattage of wall wart power supply are you using? Early 810s came with very weak power supplies, barely able to run them at the time. It could be a combination of a weak PS combined with moving parts that haven't spun or slid in decades causing it to lock up.

 

Basic drive maintenance would say to a) clean the rails with alcohol and q-tips, b) lightly lubricate the clean rails with a very light oil such as Tri-Flow or a light lithium grease c) one careful drop on the top spindle axle with a very light oil d) clean the read/write head with alcohol and a q-tip being careful of the pad *above* the read/write head (don't get alcohol on that) and e) *carefully*, *slowly* push the read/write assembly back and forth on the rails just to get it moving.

 

Finally, you might want to carefully shoot or apply some Deoxit to the powerjack and pull off and Deoxit all connectors. 

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