Help - trying to restore C1PMF

[lowrybt1]

I did try ini 25 with no luck. The stepper motor seems dead -- or nearly so. Once in a while, it will twitch when I try to boot to the drive. I swapped in my spare 610 board just to double check and nothing changed. I'll try to write a track directly without initializing the disk as you suggest. So at this point:

* able to successfully load the Boot file into the Monitor
* HO command appears to be accepted by the drive (I think OK is generated) but no operating sounds other than the spindle motor.
* ini generates an ERR #3 (track zero write error) using multiple diskettes
* sensors have been cleaned
* all wiring to/from the drive logic board are per spec
* voltages from the PSU are per spec
* MPI data separator is installed
* Drive jumpers seem to be intact

Can anyone describe what drive activity I should be seeing when powering on the drive and hitting D. Should I see the stepper motor moving as the head seeks track 0?

Thanks, Tom

[bsudbrink]

With the power off, you should be able to turn the stepper motor with little resistance.
If this is not the case, you need to lubricate the motor, the worm gear (the screw that
the head assembly "rides" on) and the assembly itself. Use "light machine" or "sewing
machine" oil. Work it until it is very easy to move.

Once the above is accomplished, with the power on, the motor should not be easy to
move. Gently test it, but don't try to force it. If the stepper is easy to move with
power on, then there is either a problem with the stepper driver or the motor itself.

If you get to this point, with the power off, move the head to about the middle of its
range. When you power on and hit 'D', the head should step to track zero.

[lowrybt1]

bsudbrink,

I lubricated the drive mechanism and positioned the r/w head as suggested. Sure enough, when I hit D, the r/w assembly moves to track zero. A sign of life but I'm left with two inter-related issues:

* (1) The head moves only when I have the ribbon cable from the 610 to the drive logic board is attached in reverse at the J1 drive connector. When the ribbon cable is in that reverse configuration, pin 1 as identified on the cable adapter is aligned with pin 30 or 34 (whatever the last pin is on the drive logic board. Is it possible that OSI installed the ribbon-cable connector backwards? The ribbon cable itself has a very obvious black dot which faces up (is visible looking down on the drive) when the connector is attached upside-down to the drive logic board. I can say this: when the cable is connected so that pin 1 of the cable lines up with pin 1 of the logic board (meaning the black dot is facing down), there are no signs of mechanical life. Hitting D in that configuration results in movement of the head.

*(2) When the drive cable is connected in reverse, loading the BootHex file that Grant so generously provided results in an automatic shutdown of the drive the minute the file executes. By shutdown I mean the LED on the drive goes dark, there is an audible mechanical thunk from the drive but the spindle keeps turning. The boot file generates an ERR #7 syntax error and any commands issued at the A* prompt generate ERR #7.

*(3) When the drive cable is connected with its supposed pin 1 attached to the drive logic board pin 1, I get no life out of the drive when booting the C1P and pressing D. However, the BootHex file loads and runs and I can enter commands like HO without getting a Err #7. However, the drive mechanicals do not respond to the command. If I move the r/w head assembly toward track 40 and hit HO, nothing happens; the head does not track back. INI (and INI 25) generates an Err #3 (track zero write error). Attempts to write directly to a track without initializing the disk fail.

I want to figure this out. I know that the problem is not the 610 board. The signals are there and I've tried two 610 boards. I know the drive is capable of receiving a signal and homing the r/w assembly when D is pressed AND the drive cable is reversed (with black dot up). The homing activity with the cable reversed suggest to me that OSI installed the connector backwards\upside-down. The drive is very unhappy when BootHex loads and the drive cable is in this reversed configuration.

Some questions: is the Err#3 possibly due to incorrect media. I'm using SSDD (soft sectored) and DSDD floppies (different brands). Both get the Err #3.

Any thoughts about my theory that the drive cable connector was installed backward/upside-down?

Thanks to everyone who has weighed in so thoughtfully on this project.

[bsudbrink]

Hi Tom,

1) Don't let this bother you. Our old friends in Hiram didn't seem to bother much about the cable stripe. I have a13s with both cables installed, one correctly, one reversed. Leave the cable plugged in in the orientation that seeks on "D".

2) This is promising. I am not familiar with BootHex but any indication that the machine is controlling behavior of the drive is a good sign. OSI had the drives wired to spin all of the time. In some game software you will frequently see a reminder message to open the drive door before you start to play. This is to avoid unnecessary wear on the read/write head and/or abrasion of the disk surface. I have seen diskettes that were left in drives where the oxide is completely worn away and you can actually see through the clear plastic. Again, I don't know BootHex, but error 7 means command line syntax error on OS65D. Maybe your load of BootHex is bad? Are you loading it through the serial port? I know it is tedious, but I would use a terminal program on your PC where you can specify an inter-character pause when "dumping" and let the data stream nice and slow. Also, I might be suspicious of bad RAM. At least, wiggle each of the 2114s in their sockets.

3) Are you sure that this isn't just "luck of the draw"? I hope you are not reversing the drive cable with the power on. That could result in "bad things" (tm). Also, are you are moving the head with the power on? Again this could be bad. If your cable orientation was incorrect, the seek on "D" would not work.

[lowrybt1]

I've been careful not to switch cables while the power is on, nor to move the drive mechanism in any way. I don't think it's bad memory: have tested this on two sets of 600/610 boards with memory that checks out okay. And I've been loading the boot file through a serial connection at 300 baud.

I keep focusing on the ERR #3. There's very little documentation about the meaning of that error code. I wonder if it means that the index hole sensor is bad and therefore the drive can't determine sector location.

[Klyball]

Hi Tom

Error 7 is fine its reacting to cr after the load, i have used it now with my 600/610 and my 510/610 to make boot disks, so the boot file should be fine

Grant

[lowrybt1]

Hi Grant,

All the indications are a problem with the MPI logic board or sensors or maybe the ribbon cable. There are no breaks or frayed edges but there are some heavy duty bends at a few points along the cable. Tom

[bsudbrink]

Could you please clue me in to what BootHex is and where I could find it?
I have a couple of C1PMFs and could give it a try here.

[lowrybt1]

I'm back to troubleshooting the disk drive on my C1PMF. I most likely have a bad logic board on the drive that is generating a faulty trk00 signal. But I'm still ruling out basic things. Here's one basic thing I'm hoping folks can help with:

What is the appropriate orientation of the small, rectangular attachment board with the floppy ribbon cable that connects to the J3 pins on the 610 board? Should the small, rectangular attachment board be affixed to J3 in such a way that the ribbon cable is oriented toward the rear of the 610/600 boards.... meaning the ribbon cable does not need to be folded back over the attachment board to exit the back of the case and that one (long) side of the small, rectangular attachment board sits above and parallel to the back edge of the 610 board?

Thanks, Tom

[bsudbrink]

Hi,

I'll repeat what I said before, if you are getting seeking when you press 'D', then cable orientation is not an issue. There could be other issues with the cable. I have seen individual broken conductors in a ribbon cable. I have also seen bad "IDC" joints at the connector itself. I'm still interested in boothex. What it is and where I could get a copy.