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810 drive won't stop spinning?

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I also looked up the stepper motor, its a Minebea Co Stepper Motor 17PS-C006-01.

Since it was five wires, I did the ohms test to find the + wire between each one, taking the lowest ohm reading. In this case I started with the black wire and each wire paired to that had equal ohms, so that means the black wire is the positive wire. Then ran 12 volts to the black wire on the stepper motor from my bench PSU and was able to cycle each of the 4 stepper wires and move the drive head from back to front and then cycle it backwards to track zero. 

 

This convinces me the stepper motor is not shorted/works OK and not feeding anything back to the side board.

 

So back to the side board and waiting on SRAM. Other than the cracked joints on the power regulators, all connections look good. 

 

May crack out the oscilloscope next. I love a puzzle :)

 

If the SRAM doesn't fix it I will be looking closer for some bad transistors. I suspect still that the stepper motor transistors may be bad, the ones that sit between the RIOT  and some diodes/stepper motor.

 

 

Edited by 7bits

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22 hours ago, 7bits said:

Narrowed it down to the side board. Data separator board is good.

the WD1771 controller usually sits on the data separator board - so does this mean you tested the data separator board (and the WD1771 on it) in the other 810?

 

 

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Posted (edited)
On 3/8/2021 at 12:43 PM, Nezgar said:

the WD1771 controller usually sits on the data separator board - so does this mean you tested the data separator board (and the WD1771 on it) in the other 810?

 

 

Yes, I got some spare supposedly working sideboard/data seperator boards but then I think I fried something trying to narrow it down :) LOL.

 

It booted once, than that was it...

 

Unless the head burned out.

 

So last place I was at, was I was able to boot off the 810 once, then went to test the data separator board, I think it worked. I swapped the smaller ICs at Z101 and Z104 from my bad side board into the good one. Then it didn't work so was ah ha!, so swapped it back, then didn't work. Thats what I get for trying to narrow down the chips :)

 

So at this point I can boot off a 1050, and initiate a format on the 810, it does the chunk chunk chunk, gets to the last track on in inner hub and sits there till it times out, this is doing a single density format on the 810.

 

The disk I try to format is a single density disk that is already formatted with DOS 2.5. Still works after the ghost format.

 

Other drives I can test the coils for the erase and read heads if I know the pinouts. Any advice on that? I guess thinking now I can check the service manual.

Edited by 7bits

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I recently go a 810 that is the always on busy light, and constant spinning mech...following this thread with anticipation.

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@7bits OK... so the drive at least gets past POST... can initiate a format, but the format is not actually erasing the disk. This would at least seemingly rule out the ROM, RAM, RIOT, and stepper.

 

if a format leaves the data on a disk previously formatted in another drive still readable afterwards, the 810 definitely isn't engaging the erase head.

 

Would be nice to have another 810 mechanism to swap in.....

 

I'm running out of specifics to suggest. Since your drive is an MPI mech with grass valley upgrades, check out the Rev 2 service manual here for some more ideas:

http://www.atarimania.com/documents/Atari_810_Disk_Drive_Service_Manual_Rev_2.pdf

 

I'd start at pp 8B-27 to 8B-28 (149-150 in the PDF) . If you have an oscilliscope you can check against the waveforms with the test points on the analog board. I'm not sure what the wave form is supposed to look like on 8B-28...

 

20 hours ago, nama said:

I recently go a 810 that is the always on busy light, and constant spinning mech...following this thread with anticipation.

Do you have another 810 or 1050 drive you can swap components into for troubleshooting?

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5 minutes ago, Nezgar said:

Do you have another 810 or 1050 drive you can swap components into for troubleshooting?

Unfortunately not at the moment.
If I'm lucky, I may be able to get a 1050 in a month or two.

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Posted (edited)
On 5/8/2021 at 8:49 PM, Nezgar said:

@7bits OK... so the drive at least gets past POST... can initiate a format, but the format is not actually erasing the disk. This would at least seemingly rule out the ROM, RAM, RIOT, and stepper.

Hello again. I've tested my 810's RIOT and the CPU by swapping them into an Atari 2600. They work fine. So this leaves me with the RAM and ROM next to test. Can I ask what component you replaced that allowed your 810 to "get past POST" ?
Thanks

Edited by nama

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2 minutes ago, nama said:

I've tested my 810's RIOT and the CPU by swapping them into an Atari 2600. They work fine. So this leaves me with the RAM and ROM next to test. Can I ask what component you replaced that allowed the 810 to "get past POST" ?

Well, as you surmised, RAM and ROM are you're next targets to swap out.

 

The 6810 is also found in the 1050, and can be found on eBay. The 2316 ROM is pretty unique to the 810, may be hard to source.... A 2732 EPROM can be substituted with modification requiring soldering...

 

Maybe see if the symptoms change with either of those removed?

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Thanks!
Can I ask what component you replaced that allowed your 810 to initially "get past POST" ?
Tonight I'm going to burn a 2732 EPROM with the Archiver image and install that (with the appropriate mods). Fingers crossed that will fix it.

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8 minutes ago, nama said:

Can I ask what component you replaced that allowed your 810 to initially "get past POST" ?

I believe this is in reference to @7bits saying he could "initiate a format on the 810, it does the chunk chunk chunk, gets to the last track on in inner hub and sits there till it times out". The fact he can interact with the drive like this means it got past POST and it was responding to commands from the computer. He had two 810's he was swapping boards and chips between to assist narrowing it down. He at least confirmed the data separator boards were both good.

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Posted (edited)

Oh...apologies. I thought it was you. 

Edited by nama

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Ok, last night I swapped in a 2732 burnt with the archiver ROM image and followed the instructions in the Archiver/Chip manual for install. No change. Endless spinning drive.
I then burnt the standard 810 (Rev-C I believe) image to a 2716 and wired that up with instruction found in these forums...that also didn't work. Endless spinning. 
So maybe the original ROM is fine(?), and my next port of call is changing out the RAM...I have some on order.
If that fails I'll have to start from scratch, and be 'lost' all over again 😞

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On 5/27/2021 at 7:58 PM, nama said:

Ok, last night I swapped in a 2732 burnt with the archiver ROM image and followed the instructions in the Archiver/Chip manual for install. No change. Endless spinning drive.
I then burnt the standard 810 (Rev-C I believe) image to a 2716 and wired that up with instruction found in these forums...that also didn't work. Endless spinning. 
So maybe the original ROM is fine(?), and my next port of call is changing out the RAM...I have some on order.
If that fails I'll have to start from scratch, and be 'lost' all over again 😞

For me it ended up being the side board. Even though I swapped every socketed chip, and the daughter board, it wouldn't work with that board....

 

I can't remember if I had trouble finding good schematics. I checked voltages everywhere and seemed good so I assumed at this point I have a bad discrete component somewhere, looking over all the solder joints, traces nothing wrong.

 

The weird thing is this does seem to be a common error state.

 

Life got busy, so I already forgot what I did, I think I gave up and swapped the guts from an 810 that has everything working as there are plenty of 810s with smashed cases, that 70s plastic is brittle!

Edited by 7bits

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