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More Floppy Woes

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pjhacnau

Experienced Member
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Apr 5, 2015
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270
Location
Morisset, NSW Australia
Sigh. I'm beginning to wonder if old floppy drives and I have irreconcilable differences . . .

So the TM100-2 was working, then it wasn't. Booting fine on my Model 1 in single density. Then it just . . . stopped. Playing a bit produced no results. So I moved it over to my Model 4 as drive 2 (yes, I did enable drive 2). Trying to read a disk sees it trying for a long time before declaring the drive empty. As opposed to immediate reporting of the drive empty when there is no disk in it. OK, I think, maybe the alignment has drifted that last bit to non-reading. So I tried formatting a drive in it A not nice noise and LS-DOS declares "Drive not in system".

Suggestions? Does that sound like it could just be heads in need of cleaning? Or something more ugly?

I've had a TP drive and this TM100 both stop working in recent times. In both cases they were connected to the Model 1 when they stopped. Is there any way the EI could "damage" the drive via bad signalling down the cable?
(Note front light still comes on for both M1 and M4 usage)


PJH
 
Last edited:
Hi PJ, I honestly do not think the Model 1 could ruin a floppy drive. This is one of the reasons I switched my Model 4 over to 3.5" drives. The FH 5.25 drives were becoming very unreliable. Or if you want to stay with 5.25 Media change to half high 360 drives. Seem to be more reliable as well.
 
PJH,
It's more likely that your floppy's are getting to the point that they deposit the brown oxide on the read head(s). And with that brown
oxide deposit, you won't be able to do anything but ruin more floppy media that you insert. That's the way I lost a most of my
old Model 1 Software.

Alcohol and a cotton swab will clean your head(s), but be very gentle as you clean the oxide from the head(s). The oxide will
be very easy to see.

Larry
 
Take one of the disks that you can no longer read and hold it up to a bright light. If you can see grooves cut in the surface, you have your answer to what's going on. There was a horrible problem with 8" Radio Shack SS media for a time that was blamed on Tandy not air-conditioning their Fort Worth warehouse. Maybe--but I suspect that they were buying their media from Wabash.
 
ldkraemer said:
Alcohol and a cotton swab will clean your head(s), but be very gentle as you clean the oxide from the head(s)
Click to expand...
A head cleaning diskette is:

1) Far more effective and way easier to use.

2) Completely safe with regard to the possibility of damaging the heads.

3) Inexpensive and reusable.

It makes no sense to me to do something manually when there is an automated, efficient, effective, safer(for the equipment) and inexpensive alternative. This is especially true when we are dealing with a problem that will likely occur over and over again simply because we are working with older/obsolete media.
 
Opening the drive to examine and clean it will identify problems that might not be helped with a cleaning disk. With a single sided drive, the cleaning disk won't clean the pad opposite the read/write head. That pad will happily scrape off all the disk material. Flippy disks will be destroyed even as the cleaning disk provides immaculate read/write heads.
 
OK, so some progress.

These things are pretty easy to work on.

Pulled it apart. The rails were quite sticky - I'm sure that wasn't helping. Cleaned the rails with IPA sprayed with dry lubricant, and refitted. Cleaned the heads with a q-tip soaked in IPA. Reassembled.

Now there is some improvement. I now seem to have a working TM100-1. I.e. single sided works, double sided doesn't. From LS-DOS I can format SS-DD-40 and have it work nicely (of course it's going to need alignment after that). But, if I try for format DS-DD-40 I get 100% cylinder failure from cylinder 0 to 39.

I never tried it DS before it stopped, so no idea if the top head was working before or not. I cleaned both heads at once (q-tip between them and spin).

Hoping for some further suggestions.

PS, there are no visible markings on any disks I've put in this drive.

PJH
 
TM100-1 is a single sided drive so it only works on the bottom surface. The top "head" should only be a piece of felt. If you have top and bottom read/write heads, you should be able to change a jumper to make it into a double sided drive.

You could make a flippy disk by punching matching holes in the disk and inserting it upside down. Please don't. It tends to become confusing.
 
pjhacnau said:
Thing is, it's actually a TM100-2. It's just now behaving like a TM100-1 :(
Click to expand...

Well, if it isn't the W1 jumper, then it must be either a broken/detached wire to the upper head or the upper head itself isn't making contact with the disk. Break out the multimeter to make sure power gets where it needs to be.
 
krebizfan said:
Well, if it isn't the W1 jumper, then it must be either a broken/detached wire to the upper head or the upper head itself isn't making contact with the disk. Break out the multimeter to make sure power gets where it needs to be.
Click to expand...

I've done a bit of checking, and I'm not sure about the voltages coming out at J3 (which feeds the heads). With the drive powered (but not running) the connector for the lower head is getting 5V, but the connector for the upper gets 0V. Is that the normal situation? Does the voltage get switched when for reading from the top head?

(PS: W1 jumper is fine).

PJH
 
pjhacnau said:
Now there is some improvement. I now seem to have [it working like a] TM100-1. I.e. single sided works, double sided doesn't.
Click to expand...
One thing you might try is switching the plugs for the heads around and try formatting a single sided disk. If that works, then that would rule out a problem with the head itself and point to a logic board issue. If that is the only drive you have, then you would have to do that after booting. Just be sure to mind the color coding as the pin numbering for each head is a mirror image of the other.

At least I vaguely seem to recall that trick works, it has been a while. Please correct me if I am wrong.

Also double check your cables to make sure the head select signal is actually getting through. If you have a logic probe, you might check that the head select signal alternates during use. Or check the cable/controller by testing with a different drive.
 
Stone said:
As mentioned previously, not using a cleaning disk is a not-so-recommended method and may result in head damage.
Click to expand...

In my experience that is very rare. Done improperly it usually results in is head misalignment which people diagnose as head failure. Realign the heads and she's good to go again.

Like anything if it's done properly its fine.

I fully agree though it's far easier and generally safer to use a cleaning disk. The one caveat which may have been mentioned is do not use a double sided cleaning disk on a single sided drive. It's likely you will rip off the foam 'support' pad which is located where the upper head normally sits.
 
SomeGuy said:
One thing you might try is switching the plugs for the heads around and try formatting a single sided disk. If that works, then that would rule out a problem with the head itself and point to a logic board issue. If that is the only drive you have, then you would have to do that after booting. Just be sure to mind the color coding as the pin numbering for each head is a mirror image of the other.

At least I vaguely seem to recall that trick works, it has been a while. Please correct me if I am wrong.

Also double check your cables to make sure the head select signal is actually getting through. If you have a logic probe, you might check that the head select signal alternates during use. Or check the cable/controller by testing with a different drive.
Click to expand...

Before I looked closely I thought the pins were a mirror image too. However, the black and white lines a swapped on the connector for the upper head. Things look like this:

Lower: Red, white, blue+yellow, black, nothing(?)
Upper: Red, black, blue+yellow, white, nothing(?)

The question mark for "nothing" is because there is something on the last line but it looks like it's for strength only.

I've checked connectivity from the connector for J3 through to the top head and it appears OK. Hence my question about a lack of +5V on the pin for the red wire on the upper connector.

PJH
 
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