Spindle won't run when 5.1/4 floppy Panasonic JU-475-3A11 is accessed

[VintageVic]

Ok,

I decided to start own thread on this issue after all, though this was mentioned in the other
thread - since I found out that the issue is not the same.

The drive is Panasonic JU-475-3A11.

And when the pc is started, the drive gives normal 'creek' sound as the stepper motor
moves slightly. Green led goes on and goes off after a short while, as I think is should.
The spindle runs a few rotations.

When I try to format a disc, the green led comes on, but the spindle will not run at all.
pc gives error track 0 bad - disk unusable. But that would be expected, since the spindle will not run,
I guess. It's not about the disc, but about the drive not spinning spindle.

I have attached picture of my jumper settings. I saw on line a pic of the correct jumper settings
and I added two white jumpers to the drive to make it according to that suggested spec. But
no difference, if I take the white jumpers off or let them be there.

On a side note, when I give "format a:" -command, the pc tries to format the disc as 360kb
floppy. If I try to format with a command "format a:/F:1.2" it refuses to do so. Pc thinks that
this is a 360kb drive, when it actually is 1.2 meg drive.

Obviously, I have configured the drive in bios as 1.2meg drive.
Also, I could force one of the jumpers to make this 1meg drive (jumper settings say fixed
density or dual density). Tried both ways, but no change. Also tried to make the drive
1 or 2 and change the cable accordingly, but that won't help either.

Perhaps it just is defective. But if anyone has had similar problem of spindle not moving, while
drive is being accessed and if had luck with repairing one with similar symptoms, please
give a hint on where to look next.



floppy.jpg

[Chuck(G)]

Try grounding pin 16 on the drive with a disk inserted and the system powered up. pinout here. You won't ruin anything as the floppy drive protocol is open-collector.

The motor should run.

[maxtherabbit]

I have two of those panasonic ju-475 drives and they are both jacked up

I'm starting to think they are just poorly made crap

[Chuck(G)]

I don't partake of the lesser Japanese brands. Are these genuine Matshushita products or rebadged someone else's gear?

[VintageVic]

Try grounding pin 16 on the drive with a disk inserted and the system powered up. pinout here. You won't ruin anything as the floppy drive protocol is open-collector.

The motor should run.

Thanks for the advice! I grounded pin 16, and the spindle did start to run.
I tried holding it grounded (just used paperclip for that) and format a disc while
spindle was running. I got again 'track 0 bad - disc unusable' -error.

While I was fiddling with the paperclip, I suddenly noticed, that I did no longer need
to ground pin 16. The spindle would spin, when I gave the format order! I do not know what
happened. Perhaps there was a bad connection with the cable or something ?

Now I noticed, that any of my high dencity disk refuse to work. The drive insists, that it
is 360kb. Perhaps it is locked in tha mode, or 1.2mb mode is failed somehow? Again,
in computer bios, I have set it as 1.2mb drive.

I tried several double density discs next. Some did not work, but several did. Well, at least
they seemed to format fine and I was able to get empty directory. I also could see
contents of the disc, that I earlier formatted with the XT 360kb drive.

However, saving to the 360kb formatted discs seem to fail. It begins to save files to disc,
but very soon saving fails. It can save some data, before the drive fails in 'abort, retry, ignore' -error.
Same issue with other discs, eventhough format commands go thrue without any bad sectors.

I can see a couple of possible causes myself.

1) the discs are dirty. Over time they get some sort of oxidy to the disc surface. You cannot really
see this by eye, but it is there. I've seen this issue with C64 discs many times - completely unusable
disc is able to be recovered by cleaning the disc surface with wet cotton stick into perfectly working condition.
I'm going to try cleaning to several discs and try again.

2) I have only preused C64 double density discs. Since they have earlier Commodore format, it may
interfere with pc format and cause trouble.

3) still other technical issue with the drive, or maybe even with the 486pc/bios, since it mistakenly
insists that the drive is 360kb and not 1.2mb what it really is.

Well, I will keep you posted of any findings I may have with this.

format.jpg

[VintageVic]

panasonic_ju_475-3.gif

Does anyone know what the jumper setting DA / UA / HA / LA
stand for ? My drive is set DA as instructed, perhaps it is "dual access".
Just guessing without knowledge.

I have TM (terminal) jumper on, since it is single drive.

I wonder what jumpers MDA, BX and MDB (or is it MD stand for ?

[rittwage]

Keep in mind the format command looks at the existing disk to determine the density, not the drive. If the disk has been formatted to 360k previously, you'll have to override it and sometimes that can be difficult. If it has not been formatted before or has other data, sometimes it gets confused and still gets it wrong. Has someone written a true disk wiping utility for DOS? I added one to nibtools years ago for C64 so I use that on 5.25" disks. Removes all flux transitions... no escaping that on any platform.

I run into a lot of these older floppy drives with bad caps these days causing all kinds of problems. Like anything else over 25 years old, recap it!

[lafos]

panasonic_ju_475-3.gif

Does anyone know what the jumper setting DA / UA / HA / LA
stand for ? My drive is set DA as instructed, perhaps it is "dual access".
Just guessing without knowledge.

I have TM (terminal) jumper on, since it is single drive.

I wonder what jumpers MDA, BX and MDB (or is it MD stand for ?

DA = Front LED controlled by drive select
UA = Front LED controlled by ready signal
HA = Front LED controlled by ready and drive select signals
LA = Front LED controlled by ready signal selecting the drive

[lafos]

I have one of these drives. I could not get it to work in my P233MMX system with an Adaptec AHA-1522A. It would fail on HD writes but would work as a 360KB drive. I put it in my Pentium III system with an ASUS TUSL2-C motherboard, and the drive worked great at HD. I never figured out why it failed with the Adaptec board. I don't use that drive much.

Had the same issues with an Epson 680 HD drive, so it was not the drive, but the computer hardware. Do you have another computer with which you can test the drive?

[Dwight Elvey]

I see your drive has drive number jumpers. If your system has a twisted cable select, the drives all have the same drive number jumper ( I forget what it is suppose to be ).
The drive is selected by the cable being twisted or not twisted.
Dwight