Coco3 drives not working (FD-501)

[cwilkson]

Hi all,

I finally set up my Coco3 tonight.  Coco, CM-8 monitor, and multipak are all working fine.  I tested several carts and they are fine.

 

But my old diskettes don't work.  (or the drives, or the controller, or....???)  I tried 7 different disks - a mix of commercial originals, my working copies of those, and some home grown disks.  They all fail to read.

 

DSKINI0...........................takes about 30 seconds or a minute or so and returns to the OK prompt.  (with no reported errors).

DIR..................................returns an empty directory.  But no errors.  This is on data and games disks and on a newly formatted disk.

DOS.................................(to boot an OS-9 game like Carmen Sandiego) hangs with some gibberish.

RUN "game name"..............returns with an NE? error.  E.g. RUN "DALLAS" to run Dallas Quest.

 

I've tried with my original RS FD-501 drive with it's original matching controller and with the dual drives that I bought from usenet 30 years ago.  All 3 drives used to work.  None of them do now.

 

I have the FD-501 controller (not working) that came with the dual drives.  It used to work but isn't recognized now.  I'll fiddle with it tomorrow to see if I can get it to work.  But I think it's something with the actual drives?

 

Any suggestions on where to start? 

[jltursan]

The easiest one is to throroughly clean the disk controllers connectors and also the CoCo One. Plug again and double-check cable connections.

You can also disassemble the controllers and pull the 1793 FDC (it usually comes in a socket), clean legs and put it back in the socket pressing it firmly (careful with the chip orientation!).

 

If the FD-501 is detected you must get the boot message "DISK EXTENDED COLOR BASIC...", if you can't see "DISK", there's a problem with the disk controller (connection or ROM part). If seems to be detected, you can start checking again the drives.

Remember to also clean the drive heads first and if possible, clean the drive inners and lubbing the rails. Try also to format the best floppy you can found.

 

The DSKINI0 command has no feedback, either doing a DIR after formatting, they simply end with OK. The best way to proceed is to write a couple of BASIC lines and save it with SAVE, then you can check again if the drive works is doing again a DIR and see if your BASIC program is listed. Try also to NEW and LOAD it back.

 

[cwilkson]

Yes, one controller is detected and the other one is not.  I wrote this in my "monitor riser" thread but failed to C&P it when I started this dedicated thread.  Here it is again:

 

Quote

One of my FD-501 controllers is recognized (power up shows Disk ECB 2.1); the other FD-501 is not recognized.  Maybe dirty edges connector?  I'll attack that problem tomorrow.

 

7 hours ago, jltursan said:

Remember to also clean the drive heads first and if possible, clean the drive inners and lubbing the rails. Try also to format the best floppy you can found.

 

The DSKINI0 command has no feedback, either doing a DIR after formatting, they simply end with OK. The best way to proceed is to write a couple of BASIC lines and save it with SAVE, then you can check again if the drive works is doing again a DIR and see if your BASIC program is listed. Try also to NEW and LOAD it back.

 

 

In the final desperate attempt last night I did the following with a random floppy in drive 0:

 

DISKINI0   [.....no feedback]

DIR   [.....no feedback]

10 PRINT "HELLO WORLD!"

20 RUN

SAVE "HELLO"  [.....no feedback]

DIR  [.....no feedback]

LOAD "HELLO"  [.....NE error]

 

If that all worked, I planned to do NEW and repeat the LOAD.  Just to be sure.  But the reads aren't happening.

 

I'll clean both edge connectors on both controllers tonight.  And on the Coco.  How do I open the controller?  Is there a screw under the label?  I hate to tear through that...both labels are pristine.  But I will if I must!

 

Regarding the drive mechanisms....

Where can I find a tutorial on cleaning and lubing the mechanism?  What type of lube to use and where?

Edited August 24, 2022 by cwilkson
typos

[jltursan]

Take a look at this video (9 minute mark).

 

He's using a white lithium grease, I prefer myself silicon based grease as it gets old much better than the white grease that tend to yellow and thickens a bit. The heads can be cleaned with care using a q-tip and isopropyl alcohol. Beware the upper head, you must be extra careful with it. Of course, if you've a cleaning disk, use it, it's far easier and gives good results.

 

About how to open the FD-502, check this other video:

 

Edited August 25, 2022 by jltursan

[cwilkson]

Well, I've exhausted my limited options.  These drives aren't going to work.

They will need professional servicing.  And who does that any more?

 

Very discouraged now.  GRRR!

 

I did try cleaning the drives as best I could, but I don't have any grease available.  I found my head cleaning diskette and ran that in the TEC FD-501 for a couple of minutes.  I didn't bother with the other 2.

 

As a last ditch curiosity thing, I tried running the disk verification routine from p.23 of the Supplement to 500 Peeks and Pokes book.

I ran it several times and got a different list of bad sectors each time.  Seems like if the disk has bad sectors they would not change with each run.  I think it's the controller or the drive itself that is bad.  Not sure where to go from here.

 

 

[jltursan]

If you get bad sectors, the drive must be working as it's capable of locate these bad sectors; so most probably you have some bad floppy disks. Of course it could also be an alignment problem of the drive heads; but at least, that means the controller seems to work and the drive mostly works as well. 

If you are sure your controller works, you can try to find a replacement drive in the form of a "modern" 3.5" floppy drive or even a Gotek unit. A Gotek is a great addition to a CoCo3!

[cwilkson]

I always intended to replace the floppy drives with a CF/SD/DW/other modern solution.  But at this point it's more about reading my old disks.  I want to see what 15 year old me was doing.  And there are some specific things that I remember doing that I want to get back again.

 

I think it's a mechanical problem.  Lots of grinding and thrashing but no joy.  Head alignment maybe?  Surely every single disk that I have can't have a bad directory sector???  I checked every disk last night.  Ugh.

 

Maybe it's a Coco3 to FD-501 problem?  I'll try to dig out my Coco2 tonight to check.  But it seems very unlikely to make a difference.

 

 

 

 

 

 

 

[jltursan]

Did you test your CoCo2?, I guess that the drives failed the same way.

If so I would go definitely the 3.5" or Gotek way, but just to diagnose the problem. If you can be sure that the problem lays in the drives and the controller works, it's just a matter of look for a 5.25" drive replacement.

[cwilkson]

I finally got back to this.

Last night I opened up the spare/non-working controller cart.  C9 had leaked electrolyte and completely destroyed a few traces and damaged many others plus the +5V card edge finger.

Tonight I cleaned and repaired the traces and replaced C9.

 

IT WORKS!

I tested both drives in my non-Tandy dual-drive unit and they both work with the repaired controller.  JOY! JOY!

I didn't try the official RS FD-501 drive (with the TEC FD-501 inside) yet.  But I'm guessing that it will work too.

 

I was able to read a few disks and see some of my 19-year-old-self's work, and start a game of Blackbeard's Island.  I forgot about color artifacting...the game was not playable on the RGB monitor.  But it was working!

OS9 games are not working using the "DOS" command.  The drives just grind a couple times, "OS9 BOOT" is displayed, and the disk spins forever.  I need to look into that.

 

Next up...make new drive cables because the old ones are falling apart.  And test the remaining drive mechanism.  And get a composite monitor set up for game playing!  And figure out OS9 games issue...

 

 

 

 

[MrDave]

Good job !  Your eyes are the best tool for these old systems to find problems..

Speaking of which..try and get setup to use the rgb out for a sharp nice color picture..if you can't find a cm8 or other rgb , try going from rgb to hdmi..( switcheroo cable )

 

 

[cwilkson]

5 hours ago, MrDave said:

Good job !  Your eyes are the best tool for these old systems to find problems..

Speaking of which..try and get setup to use the rgb out for a sharp nice color picture..if you can't find a cm8 or other rgb , try going from rgb to hdmi..( switcheroo cable )

 

Thanks!  A little internet reading, a lot of scraping and scrubbing, and a LOT of magnification, flux, and IPA and that controller is good to go!  Still need to seal every thing with clear nail polish, but it's working. 

 

On 8/24/2022 at 2:37 AM, cwilkson said:

I finally set up my Coco3 tonight.  Coco, CM-8 monitor, and multipak are all working fine.

First line of my OP. 

 

Yes, the CM-8 looks great!  RSN, I'll have an Apple IIe setup with a Sony PVM next to the Coco.  Then I'll use the PVM for Coco composite to support color artifacting.

 

Any idea on why the OS9 boot (using DECB "DOS" command) doesn't work?

Is it a conflict on the Coco 3?  I KNOW I played Rogue BITD.  And Carmen Sandiego.  On this machine, with these drives, and with these actual disks.  So I can't believe that it's an incompatibility thing.

I've tried those 2 games with the OEM disks and backup disks that I made.  And a second backup that I found for Carmen.  None work.  All of my other disks that I've tried are reading fine.  But every OS9 disk is failing!  WHY?!!