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spinnaker15136

SIO coding for Atari 400/800 examples?

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provided you have a DOS 2.0 disk inserted after the drive is turned on and then power up the 800 you should get get a DOS menu etc. If you turn on the drive while a disk is still in it the disk could get corrupted, if you turn the drive on after the 800 is on, you won't get anytghing either.

 

check a101 a104 a106

 

go to page 8c-24 of the manual near 195 of the pdf...

 

although considering the way you are posting and how this is going, maybe you should consider pdf page 184, 8c-19 in the fsm...

 

follow the clearly laid out logic/block/flowchart diagram, it contains simple yes no questions to walk you thru this and it also provides voltages and scope examples.

 

this will walk you thru from power up on.

 

check out the 4069 while you're in there

 

alternatively page 134 of the pdf appears to have another set you can follow as well...

 

it really shouldn't take too long to work through this.

Edited by _The Doctor__
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provided you have a DOS 2.0 disk inserted after the drive is turned on and then power up the 800 you should get get a DOS menu etc. If you turn on the drive while a disk is still in it the disk could get corrupted, if you turn the drive on after the 800 is on, you won't get anytghing either.

 

check a101 a104 a106

 

go to page 8c-24 of the manual near 195 of the pdf...

 

although considering the way you are posting and how this is going, maybe you should consider pdf page 184, 8c-19 in the fsm...

 

follow the clearly laid out logic/block/flowchart diagram, it contains simple yes no questions to walk you thru this and it also provides voltages and scope examples.

 

this will walk you thru from power up on.

 

check out the 4069 while you're in there

 

alternatively page 134 of the pdf appears to have another set you can follow as well...

 

it really shouldn't take too long to work through this.

 

 

We must not have the same 810 service manual. The one I have only has 10 chapters. Last page is 10-5.

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downloaded from the very links I provided you...

and now posted here.

 

attachicon.gifAtari_810_Disk_Drive_Service_Manual_Rev_2.pdf

 

please take the time to examine what everyone is providing you.

 

 

Oops sorry. Not thinking. Just got back from the emergency room for my 93 yo mom for the second time this week after giving her the Heimlich for the second time this week. Finally got them to admit her tonight.

Edited by spinnaker15136

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Well I really should be headed off to bed but had to giv that flow chart a quick look first.

 

If I followed things right I get to Does motor and busy light go off after 7 seconds which it does. So I go to 8C-22 which is the diagnostic cartridge which I do not have.

 

I will try to check out the rest tomorrow but need to get some sleep. ;)

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Making big progress. Reseatted all chips again. Also Q104 appeared to be smashed down with leads touching. Straitened the leads. Disk drive is now responding to power on of computer but I get a boot error. I am on a work break from my real work right now but wanted to give this update. Later I will look at the manual for timing procedure.

 

At least SIO appears to be working. ;)

Edited by spinnaker15136
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Trying to follow the calibration procedure. First I don't know how they expect you to get a probe clipped onto those components. ;)

 

 

C155 looks like a resistor to me. C154 a diode? Maybe a glass cap? Never saw one of those. Am I reading the diagram correctly? Probe goes on the "top " of C154 and "bottom" of C155?

Edited by spinnaker15136

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a variety of probe tips exist. do a search for oscilloscope probe tips, mini grabber, there are all measure of pressure stands/position holders etc... under various names....

 

while not at a location to take a quick look, Atari used glass caps and caps that looked like resistors, I'd suspect if it says it's a capacitor... it is, you can double check by flipping to the parts list in the fsm and read the description...

Edited by _The Doctor__

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So can I do at least part of the alignment procedure without the special disk and cartridge?

 

 

Will the 1050 alignment kit work on the 810? From what I remember Best sells both. Would be nice to be able to buy just one in case I get a 1050.

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Does a better schematic exist for the 810?: The one in the linked manual is not very readable. I am trying to find the 7812 circuit. A 7812 is connected to J104 correct? I seem to have some issues there.

 

 

 

 

12V output

post-68113-0-12480000-1556147796.png

 

 

5V noise

post-68113-0-51810300-1556147738.png

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Found a manual with a better schematic. Seems to be a slightly different Rev. The one linked above lists a 7812 for some reason, which is really condusing as there does not appear to be a 7812 on the board.

 

 

 

810.pdf

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I don't have an 810 but as far as I know, the 810 and 1050 both have 12VDC power rails, with a 7812 doing the heavy lifting. Just dig out a regular multimeter and measure the output of the voltage regulators and find it..

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810 definitely has a 7812. 12V is needed to power the drive motor. It will be screwed to the bottom aluminum plate horizontally.

 

The triangle wave above may be the rectified 18V after the voltage doubler but before smoothing capacitors? Yeah need to see what's going in and coming out of the 7812... but 12V isn't used by the controller electronics, so I'd focus on the 5V. But then again, your drives POST behaviour seems is normal, so maybe we need to focus on the I/O side...

 

If it was a 1050, I/O stuff can blow if the barrel blug power connector is disconnected while the PSU is live. I'm not sure if this is a risk for the 810 as well.

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There is no 7812 in the 810 schematic. There is only 9VAC in so the best they can do is ~8VDC. They use a boost switcher (they call it a doubler) to get 12V from the regulated 5V (7805).. Regulators are not my strong suit and it has been 40 years since I was in tech school but this is the way I understand it. . The BOM on the linked manual above lists a 7812. but gives no part number nor component number.. The manual I attached does not list it at all.

 

 

There are only 3 TO220 packages in the 810. Two are clamped to the base plate. One of them is a 7805 and the other a power transistor Q113. The other t0220 is near the SIO connector and it is another transistor. It has a clip heatsink. If there is a 7812 on board I would like to know where it is.

Edited by spinnaker15136

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Triangle wave is coming from the switcher. But I dont't know if that is noraml or not to be sitting atop the 12V like that. I would think that switcher would have its own filter cap but I see none.

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Another thought... Very old 810's from 1979 to late 81 had a notoriously bad power board, no data separator (second PCB attached to the side board) or analog board on top of the mechanism.

 

Does your drive differ from this picture in any way? This is the (earlier) MPI mech. 810's mfg after November 82 may have a Tandon mech.

post-53052-0-51588500-1556165274_thumb.jpg

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the link was given for him to go to Atari Mania if he needed a rev 1 fsm. the rev 2 fsm contains tech tips and new power board et al. Everything has been provided short of a van appearing and one of us doing the repair curbside. The provided download if I remember correctly- was because he didn't go to Atarimania link I provided to get it, so I put the one I had handy up to get him started. It's best to update the drive to the later power board and make sure it was up to rev 2 spec in any event.

 

Thanks to the AA crew for helping out, he'll get it worked out soon.

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Just took a pic of my caseless 810. 7812 on the power board.

 

 

That is NOT a 7812. I thought is was at first too. The circled is Q113. It is a power transistor. Regulation is provided by Q114 and Q115. I am getting reasonably clean power on pin 2- of the connector. So I need to ohm out the board and see what I thought was the collector on Q113.

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the link was given for him to go to Atari Mania if he needed a rev 1 fsm. the rev 2 fsm contains tech tips and new power board et al. Everything has been provided short of a van appearing and one of us doing the repair curbside. The provided download if I remember correctly- was because he didn't go to Atarimania link I provided to get it, so I put the one I had handy up to get him started. It's best to update the drive to the later power board and make sure it was up to rev 2 spec in any event.

 

Thanks to the AA crew for helping out, he'll get it worked out soon.

 

 

I DID go to the link you provided thank you. In my post above you will see that I could not read the schematic so I found another copy.

 

Does Best carry the updated 810 power boards? I will try and look around on their site later this after noon.

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Another thought... Very old 810's from 1979 to late 81 had a notoriously bad power board, no data separator (second PCB attached to the side board) or analog board on top of the mechanism.

 

Does your drive differ from this picture in any way? This is the (earlier) MPI mech. 810's mfg after November 82 may have a Tandon mech.

 

 

My power board looks the same. Drive is different. So what does the updated one look like?I will upload a pic of mine in a bit.

Edited by spinnaker15136

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That is NOT a 7812.

Hmm. In my picture, the circled component is at J105, and has MC7812CT printed on it, which the datasheet says is a Motorola "3-terminal 1A positive voltage regulator" output of 12V with 4% tolerance.

 

Edit: I haven't looked at the schematics you're looking at, but maybe they're for the old power board. My drive has the newer power board. (1981 = newer? Hehe)

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Hmm. In my picture, the circled component is at J105, and has MC7812CT printed on it, which the datasheet says is a Motorola "3-terminal 1A positive voltage regulator" output of 12V with 4% tolerance.

 

Edit: I haven't looked at the schematics you're looking at, but maybe they're for the old power board. My drive has the newer power board. (1981 = newer? Hehe)

 

 

Not mine.

 

CO

14786

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