Cannot image any disks

[yuv422]

I haven't had any success imaging any disks with my greaseweazle v4.

I have a 3.5" samsung floppy drive with a twisted cable and external power supply. I can seek the disk and see the drive spinning in read mode.

But I just get errors whenever I try to do a read.

./gw.exe read --format=ibm.scan test.img
Reading c=0-79:h=0-1 revs=2
Format ibm.scan
** FATAL ERROR:
Track0 signal absent after seek to cylinder 0

./gw.exe read --format=ibm.scan test.img
Reading c=0-79:h=0-1 revs=2
Format ibm.scan
Command Failed: Seek: Track 0 not found

The same drive, cable and disk works correctly on my 486 computer. I can image disks just fine there.

Any ideas what I could try to get it working with the greazeweazle?

[keirf]

It seems the drive isn't seeking reliably. You could try adjusting the step rate using the command gw delays --step 3000 for example to increase the step rate to 3ms per step, or specify 20000 to slow it down to 20ms per step.

[keirf]

It might be that the pc is more forgiving of a sticky stepper motor or worm gear, for example.

[yuv422]

I gave it a try and it didn't make a difference.
I tried bumping all the delays a bit

./gw.exe delays
Select Delay: 20us
Step Delay: 10000us
Settle Time: 60ms
Motor Delay: 2000ms
Watchdog: 10000ms

I did notice that if I do a seek 0 it moves the head to the edge of the disk. If I then do a read it will move the head slightly towards the center of the disk. It then gives me the error. If I then try to do another seek 0 I get an error.
If I seek to a different location it works and I can then seek back to 0.

Eric@DESKTOP-MINGW64 ~/greaseweazle-1.14
$ ./gw.exe seek 3

Eric@DESKTOP-MINGW64 ~/greaseweazle-1.14
$ ./gw.exe seek 0

Eric@DESKTOP-MINGW64 ~/greaseweazle-1.14
$ ./gw.exe seek 0

Eric@DESKTOP-MINGW64 ~/greaseweazle-1.14
$ ./gw.exe read --format=ibm.scan test.img
Reading c=0-79:h=0-1 revs=2
Format ibm.scan
** FATAL ERROR:
Track0 signal absent after seek to cylinder 0

Eric@DESKTOP-MINGW64 ~/greaseweazle-1.14
$ ./gw.exe seek 0
** FATAL ERROR:
Track0 signal absent after seek to cylinder 0

Eric@DESKTOP-MINGW64 ~/greaseweazle-1.14
$ ./gw.exe seek 1

Eric@DESKTOP-MINGW64 ~/greaseweazle-1.14
$ ./gw.exe seek 0

[keirf]

Maybe the track 0 sensor is somehow unreliable or marginal. It's just a mechanically secured photo sensor.

[yuv422]

Good point. I'll see if I can get another drive to test.

[aurum79argentum47]

My Shugart SA400L does exactly the same thing. Brand new (new old stock) photodiode and photsensor for track 0 sensor, calibrated per service manual.

Switches do not help.

[keirf]

Have you tried increasing the step delay to 20000us or beyond? Manual says the step latency is 20ms on this drive.

[aurum79argentum47]

Yes, I've tried this after reading the previous posts. I'm about to give up on these two old Shugart 400's with GW. They work great on the TI-99/4A but maybe they are just to sloppy for this precise controller.

[Zalorpas]

Could you, please, share the Samsung FDD model? It might help for the troubleshooting
Thanks,

[aurum79argentum47]

I'm not the Samsung guy. I tried a Mitsubishi M504C-368U (5-1/4" HD) with sucess.