Not Calibrating Disk System Correctly?

Started by Trashman, October 25, 2022, 03:16:02 pm

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Trashman

Hello,

I acquired a Famicom Disk System awhile back and finally got around to checking it out. After replacing the broken belt (ordered from here) and attempting to calibrate it via watching a Youtube video I got:

Side A: Error 27
Side B: Error 22

I attempted to recalibrate using this video as a reference. (Note: I did not remove the springs or black disk 'housing', just got my allen wrench in there to loosen/tighten the screw on the drive spindle):

Side A - Error 27
Side B - Side A / B error (something like that)

Finally I attempted again with this method:

Side A - Error 22
Side B - Error 22

I only have one Famicom Disk that I've been using to test with, so I can't be 100% sure it's working, but I got the impression from my 2nd attempt it was being read correctly due to the 'Side A / B' error.

Should I acquire more Famicom Disks first to attempt with my testing, or is it more obvious that it needs to be calibrated in a different way? As an aside, I bought an FDSStick (+ parts to make the cable) with the intention of eventually writing a copy of Zelda no Densetsu to disk and playing off that.


Skawo

October 25, 2022, 11:22:13 pm #1 Last Edit: October 26, 2022, 03:40:44 am by Skawo
Well, it could several things.

Assuming you put the belt on right;

The 'Hobby World' video shows the correct method of aligning the spindle - screw facing the reading head when the bay is furthest away from it. The second one is nonsense as far as calibration goes - it probably gets it close enough for some drives to work, but not for all of them. The second video does show a good way of replacing the belt, though.

While adjusting the spindle, make sure it's not raised too high, or the disk will rub.

If that doesn't work, there's a few possibilties;

First, and the most likely, is that the disk you have is bad or rewritten on a misaligned drive. Does the label match the disk contents? If you got it from someone that claimed it worked, perhaps it was rewritten by them and THEIR their drive wasn't aligned quite right. If the drive rewriting the disk isn't aligned right, then it just won't work on most other FDSes.
If that is the case, you could probably get the disk to load by adjusting the spindle a few degrees counterclockwise at a time and re-checking if it reads after each adjustment, but you'll just match the wrong alignment someone's had.

Second option is that the drive needs to be relubricated. I've had a drive where the old grease made the read bay struggle to get to the starting position, but it was still hitting the return switch - this made it start reading too far into the disk and resulted in most disks not working. Fixing this would require taking off the black part, cleaning off the old grease and putting some new one in (lithium-based, for example).
It's also possible that the pad under the pressure arm is missing, which would make the disk not touch the reading head.

Third option is that the motor speed is critically wrong, or the read head alignment screw has been adjusted out of whack. However, as long as someone hasn't messed with it I've not seen it get so bad that disks wouldn't read. But, if you wanna pursue that avenue, there's a good thread here:
https://tinkerdifferent.com/resources/famicom-fds-drive-calibration-wip.52/updates


tldr; Generally, I would try to adjust the calibration as shown in the "Hobby World" video and tried another disk (making sure it's an original, unmodified copy) before trying anything more invasive.

Trashman

Quote from: Skawo on October 25, 2022, 11:22:13 pmThe 'Hobby World' video shows the correct method of aligning the spindle - screw facing the reading head when the bay is furthest away from it. The second one is nonsense as far as calibration goes - it probably gets it close enough for some drives to work, but not for all of them. The second video does show a good way of replacing the belt, though.
Okay this, is good information. I didn't know which one was the accurate way of doing it. Question in regards to this - when you rotate the wheel and the drive spindle 'pops' backwards, it seems like there's a tiny bit of space left for it to move back a bit more - Should I try and get it to go back even farther (aka as far away from where I believe the read/head is located)?

Quote from: Skawo on October 25, 2022, 11:22:13 pmWhile adjusting the spindle, make sure it's not raised too high, or the disk will rub.
When I tighten the spindle, I let gravity essentially keep it as close to the metal below it as possible, is this correct? Or should I have some extra space there (maybe a sheet or two's worth of paper?)

Quote from: Skawo on October 25, 2022, 11:22:13 pmFirst, and the most likely, is that the disk you have is bad or rewritten on a misaligned drive. Does the label match the disk contents? If you got it from someone that claimed it worked, perhaps it was rewritten by them and THEIR their drive wasn't aligned quite right. If the drive rewriting the disk isn't aligned right, then it just won't work on most other FDSes.
If that is the case, you could probably get the disk to load by adjusting the spindle a few degrees counterclockwise at a time and re-checking if it reads after each adjustment, but you'll just match the wrong alignment someone's had.
This I don't know. I can't recall where I got the disk from, but I know I bought it separately. The label says it is Jikai Shounen Met Mag developed by Square. I can't even recall if the listing said it was good or not. I think I will try and acquire some additional disks just to hedge my bets here. I will attempt to adjust the spindle counterclockwise if all else fails.

Quote from: Skawo on October 25, 2022, 11:22:13 pmSecond option is that the drive needs to be relubricated. I've had a drive where the old grease made the read bay struggle to get to the starting position, but it was still hitting the return switch - this made it start reading too far into the disk and resulted in most disks not working. Fixing this would require taking off the black part, cleaning off the old grease and putting some new one in (lithium-based, for example).
It's also possible that the pad under the pressure arm is missing, which would make the disk not touch the reading head.
I'm 99% sure the pad is still there, but I'll check when I'm at home later. I didn't get the impression that the drive was struggling to move back and forth, but I'll evaluate re-lubricating (the rails?) if nothing else works.

Quote from: Skawo on October 25, 2022, 11:22:13 pmThird option is that the motor speed is critically wrong, or the read head alignment screw has been adjusted out of whack.
I'm hoping this is not the case, as I'm thinking I may not have the technical know-how to get this done, but we'll see.

Thank you for your help!  :D

Skawo

October 26, 2022, 10:52:52 am #3 Last Edit: October 26, 2022, 11:00:40 am by Skawo
Quote from: Trashman on October 26, 2022, 10:45:47 amQuestion in regards to this - when you rotate the wheel and the drive spindle 'pops' backwards, it seems like there's a tiny bit of space left for it to move back a bit more - Should I try and get it to go back even farther (aka as far away from where I believe the read/head is located)?

As soon as it pops is where you want the spindle screw facing the head.

Quote from: Trashman on October 26, 2022, 10:45:47 amWhen I tighten the spindle, I let gravity essentially keep it as close to the metal below it as possible, is this correct? Or should I have some extra space there (maybe a sheet or two's worth of paper?)

In my experience, yes. I _think_ it should be as low as possible, as long as the  disk actually spins. If it doesn't, only then you would raise it.

Quote from: Trashman on October 26, 2022, 10:45:47 amI'm 99% sure the pad is still there, but I'll check when I'm at home later. I didn't get the impression that the drive was struggling to move back and forth, but I'll evaluate re-lubricating (the rails?) if nothing else works.

If you can, you could upload a video showing the drive moving back and forth. I'd be able to tell.

Stephen

Quote from: Skawo on October 26, 2022, 10:52:52 am
Quote from: Trashman on October 26, 2022, 10:45:47 amWhen I tighten the spindle, I let gravity essentially keep it as close to the metal below it as possible, is this correct? Or should I have some extra space there (maybe a sheet or two's worth of paper?)

In my experience, yes. I _think_ it should be as low as possible, as long as the  disk actually spins. If it doesn't, only then you would raise it.

I apply very light pressure during servicing / calibration; my goal is to ensure it's flush with the surface of the brass collar without unnecessary additional pressure. More or less, the weight of my fingers hold it in place.

Trashman

Quote from: Skawo on October 26, 2022, 10:52:52 amAs soon as it pops is where you want the spindle screw facing the head.
Got it.

Quote from: Skawo on October 26, 2022, 10:52:52 amIf you can, you could upload a video showing the drive moving back and forth. I'd be able to tell.
I will try to do this when I get a chance.

Quote from: Stephen on October 26, 2022, 03:12:39 pm
Quote from: Skawo on October 26, 2022, 10:52:52 am
Quote from: Trashman on October 26, 2022, 10:45:47 amWhen I tighten the spindle, I let gravity essentially keep it as close to the metal below it as possible, is this correct? Or should I have some extra space there (maybe a sheet or two's worth of paper?)

In my experience, yes. I _think_ it should be as low as possible, as long as the  disk actually spins. If it doesn't, only then you would raise it.

I apply very light pressure during servicing / calibration; my goal is to ensure it's flush with the surface of the brass collar without unnecessary additional pressure. More or less, the weight of my fingers hold it in place.
Okay, this is more great info. I may have to remove the springs / black plastic housing since I don't think I can get my fingers in there when the spindle 'resets' to the rear.

Trashman

Attempted to re-calibrate again following the Hobby World video, however I did not remove the black plastic 'disk holder' housing on top, just got my finger in there to hold down the head while I tightened the set screw.

Quote from: Skawo on October 26, 2022, 10:52:52 amIf you can, you could upload a video showing the drive moving back and forth. I'd be able to tell.

Here's the current operation 'speed' of the FDS drive

On the plus(?) side, if I flip my game to Side B, the FDS throws "A,B SIDE ERR.07" again, which tells me it knows that it's on the wrong side and is reading better than just 'Error 22'.

I am in the process of acquiring some more FDS disks from the land of the rising sun. I imagine it'll take a few weeks for them to arrive before I can do more in-depth testing.

Stephen

Quote from: Trashman on November 04, 2022, 04:02:16 pmHere's the current operation 'speed' of the FDS drive
I can hear in the first video that something is rubbing on the gear train. This can often lead to read issues. A well calibrated drive will make very little noise and will not make a rubbing noise.

Skawo

November 05, 2022, 09:55:01 am #8 Last Edit: November 06, 2022, 05:15:04 am by Skawo
Yeah, that operation seems a bit slow to me, too.
You could try and see if the drive reads if you turn it upside down and let it run a few times (just make sure the reading hub isn't stuck on anything).

It may be that the belt is slipping off and rubbing against the metal triangle on top. Running the drive upside down sometimes helps with that, although obviously that's not a permanent fix, just a thing to check.

Trashman

Okay, sorry for the delay.

So the order I put in for additional FDS games finally came in today.

Decided to follow the advice of checking for rubbing, and attempted to get the belt to sit lower on the large gear, rather than up near the metal triangle. Not sure if that worked or not, so then I put the whole thing back together (somehow losing the screws for the front black plastic part along the way) and flipped the FDS upside-down.

I attempted my original game...and it worked!  ;D

I tried 3-4 other titles, and they all worked. Decided to go for it and turned the whole thing right-side up. Attempted another batch of titles, and they all work.

Now, when they 'initialize' or whatever, I'm hearing sounds from the drive; I'm not sure how silent the whole thing is supposed to be. I always assumed it was going to have some noise since, well, it's old tech.

My only question is about some of the games - they have graphical glitches that appear from the get-go and persist through gameplay - like a specific few sprites or areas that are always flashing/jumping. An example of this is Jackal - the Jeep is always glitching out as I move it around, and some other areas of the game are doing the same, but the whole thing is playable. I'm assuming this is either because of the age of the disc or dust is in there or something - not quite sure since it's new territory. Thoughts?

Skawo

Well, you'd have to show us what kind of glitching it is.
Kinda sounds like a PPU issue in your console (not the disk system)?
Are you using a real famicom/sharp twin/famicom av for this? Famiclone compatibility seems to vary.

ericj

Have you tried a different RAM adapter to see if the glitches go away?

Trashman

Quote from: Skawo on December 03, 2022, 12:39:46 amWell, you'd have to show us what kind of glitching it is.
Kinda sounds like a PPU issue in your console (not the disk system)?
Are you using a real famicom/sharp twin/famicom av for this? Famiclone compatibility seems to vary.

Real FDS with RAM Adapter running to AV Famicom. I also have an FDSStick.

Quote from: ericj on December 03, 2022, 09:55:10 amHave you tried a different RAM adapter to see if the glitches go away?
I don't have a spare...

So I did some testing with different disks as well as the FDSStick. Some games seem to run completely fine, others exhibit the glitches; I've attached some videos of a few examples.

https://imgur.com/a/pgRBLJI

Since the glitching persists with the FDSStick this leads me to believe it's the RAM adapter. Is this something common that can be fixed? Or am I on the wrong track here?

Skawo

December 08, 2022, 01:27:54 am #13 Last Edit: December 08, 2022, 01:36:39 am by Skawo
Could be this problem, perhaps?

https://www.famicomworld.com/forum/index.php?topic=10607.0


(tldr; older, revision 2 and 3 RAM adapters with smooth plastic sometimes don't work with some newer famicoms unless some resistors are added)

Trashman

Quote from: Skawo on December 08, 2022, 01:27:54 amCould be this problem, perhaps?

https://www.famicomworld.com/forum/index.php?topic=10607.0


(tldr; older, revision 2 and 3 RAM adapters with smooth plastic sometimes don't work with some newer famicoms unless some resistors are added)
It looks like it. The YouTube link in that thread seems to showcase exactly what's going on with my setup.  I do have an OG Famicom that I can try out, but I wasn't using it b/c it's completely unmodified - RF & 3 ft cords  :(