Help - trying to restore C1PMF

[lowrybt1]

Dave,

Once again, thanks for all the guidance. I'm going to implement the mod to get the baud to 9600. But before doing so, would appreciate your read (or anyone's) about a few modifications made by the previous owner of the c1p I'm working on. First, U67 and U68 have IC's installed both accompanied by a bunch of resistors.

There is wiring connected to leads which seem to run back to pins 23 and 24 of the ACIA.... seems perfect for a switch. So I'm wondering if this board already has a baud rate modification in place. I've also included a photo of the RS232 components if anything to show off the nails driven into the J3 connector.

Tom

[dave]

Hi Tom,

That's the 20-ma current loop hardware. You can safely ignore it, except that you use the RS232 interface, you will want to make sure that the jumper is set for RS232 input, rather than 20-ma input. If you use the FTDI interface directly to the UART, then the jumpering is not relevant.

The best way to check your baud rate is to determine what pin 2 of U57 is connected to.

Good luck,

Dave

[MK14HAK]

Tom did you replace U58 on first SB? I have seen those go before.
Do you still have a working drive ? Any software ?
Mike

[lowrybt1]

Mike,

I just got the replacement IC for U58 and will install it this weekend. Tom

[lowrybt1]

Ok,

The adventure continues. With immense help from Grant and Dave and others, I've reached a point where I'm cross loading code from my Mac to my C1PMF in an effort to build\write Disk #5 of OS-65D. My floppy drive is behaving oddly at a critical point in the process and I'm working to diagnose that. One concern I need to rule out is the possibility that some of the cable connections on the drive's PCB (original MPI B-51) are wrong.

I've attached two photos showing the connections. I'm wondering if I have the ribbon cable upside-down\backward. The MPI manual says odd pins on the cable connected to J1 are on the solder side of the drive PCB. The other head scratcher.... There is a power\signal coupling labeled P3.2 on the PCB toward the front of the drive case. I can't find P3.1, so I'm wondering if something fundamental is missing.

Finally, I want to double check that the drive cable connection at the 610 board is attached correctly. Any hints for how to be certain I have that connection correct? I can't find a pin 1 identifier around those connections.

Thanks, Tom

[Klyball]

Hi

you are not missing any connections that empty plug is for a mpi 52 for the head on the other side if it had one.

i needed to have the HM jumper closed on mine bottom left of the picture.

Give that a go

pin 24 is closest to the edge of the 610

[lowrybt1]

Grant,

Okay. More progress. Got to A*. Typed INI. Sure: Y.

I immediately get ERR#3. "Track zero write protected against that operation." I tried different diskettes and got the same result.

I'm now going to clean the sensors to see if that clears the error.

[MK14HAK]

Tom, possible tk0 sense line stuck lo or sensor. Also check your DOS in winOSI and try images from Mark winOSI site: http://osi.marks-lab.com/
Will it do A* IN 01 ??

[lowrybt1]

I think I've hit a dead-end getting my MPI B-51 to work. The voltages going to the PCB and drive motors are good. I can verify that the drive is receiving signals from the 610. All connections between the drive logic board and various motors and sensor are correct. The spindle is turning at 300RPM. But it ends there. INI produces an ERR #3, not the disk write protect error but a track 0 write protect error. HO does not generate an error but it also doesn't seem to work -- the stepper motor is not activating. When I first took the machine out the box a month ago and powered it up, the drive did come to life briefly, meaning I saw the stepper motor working. Short of finding another MPI B-51 that is intact and working (what are the odds?) that's it.

I could try to build a data separator and hook up to a different make of drive but my diy skills have limits.

I can say it has been real fun getting to this point and seeing that there continues to be an active OSI community!

Tom

[Klyball]

Did you try ini 24 or some other track the higher the better ini does the whole disk but you can do individual tracks.