...Another 810 Thread

[nama]

Hi all, 
Over the weekend I was able to get my 810 drive partially working.

I replace the RIOT (which tested dead in my 2600) and burnt a new (E)PROM. Previously the drive would spin endlessly and the head would never move as it should. After the fix the drive would spin then stop and the head would do its usual movement. However all my disks would not boot (I suspect many are the wrong density) except one. The floppy that worked is a multi games disk, and I was able to boot to the games menu, but not able to actually load any games from there. I suspected the drive speed so I tweaked it using some drive speed software to be exactly 288rpm. After I did that now nothing loads!!!!

Weird!

Head is clean. and I get a lot of knocking as the head hits track 0.

Wondering if anyone has any insights. Alignment???

Thanks

 

[nama]

Hi, Here is an update.
After applying a bit of pressure to the pressure arm I was able to get the drive to load a game! I thought I would do the pressure fix as described in the field manual. After doing this I wasn;'t able to load anything...bummer ?
after much fussing around I was only once able to load the games menu as before. So not sure why I made things worse. But at least I still know the basic function of the drive is still working. I guess there may still be a pressure issue, but also likely an alignment issue.
I have made myself an 810 diagnostics cart and will use that to attempt to perform a alignment test/fix. It took some searching to find that the probe points on the upgraded 810 drives are TP2 and TP3 on the drive analog board (for your future reference).

[+kheller2]

You probably will need a master alignment disk if you plan to play with head alignment.   As is always said, make sure those heads are clean.   The diagnostic card should have a RPM test on it.  You mentioned that you did set it to 288 and then couldn't load anything -- could it be the disk that doesn't load was written at the wrong RPM?  How far did you have to tweak it?

[_The Doctor__]

use the pressure spring adjustment slots(depending on the mech)/or the rabbit fur pressure pad head spring tension-- rather than your finger and adjust rpm without finger assistance. You more than likely are over-pressuring the head and slowing the disk, your' 288 is more than likely an average of uneven pressure and sector readings, take away the uneven reading and disk drag by removing your finger and the rpms' will be too fast to read. If the head spring is weak or missing, replace it, or remove it, stretch it and put it back in...

 

the other thing I've seen is people bending the flex metal on some mechs when using fat q tips to clean... you would have to take the pressure arm flex head off the top and bend it back (you can't do this still attached as it could compress the pressure spring or damage the actual head...

Edited November 17, 2021 by _The Doctor__