P112

[allison]

On 04/08/2018 04:11 PM, Bill Gunshannon via cctalk wrote:
>
> On 04/08/2018 02:11 PM, Fred Cisin wrote:
> Radio Shack used a different approach to drive select by cable instead 
> of making use of the well documented drive select on the drive.
> Radio shack jumpered all drive selects on on the drive, and pulled 
> pins in the cable.
>
OR used a straight cable and people used the drive select.

>>> I need to get the systems running before I start playing with reading
>>> and writing weird formats.  But that is coming.
>> Should be fun.
>> Is the FDC a 765 variant?
>> or a WD 179x variant?
> SMC 37C651.  Supports  500 Kb/s, 300 Kb/s and 250 Kb/s Data Rates.
> Something else we lost with the PC.
The 37C651 is 765 variant,  so any PC should be able to create a
compatible disk.
Least for my CP/M systems its never been an issue.  considering I'e used
8/5.25/3.5 drives
on the same boxes it should not be a big deal.

Some notes:  The 37C651 and its kin all have minimal drive so long
cables are
out as they pick up noise.  Keep the cable away from monitor (crt based)
and any
switching power supplies.  Use a separate ground wire from the drive
frame to
the board ground.

The IDE interface same deal, short cable only and one drive.  CF works.

When making a disk first ERASE IT using a degausser then format and copy
to it.
Also make sure the drives are the same TPI, your trying to make life easier.
I've had the best luck with older PC 5.25 like Toshiba and Teac.  For
3.5 Sony
and Toshiba are the go to but if all else use the same drive to write it
and read
(that means moving it).

One last detail make sure all the voltages (+5, +12,-12) are good and clean.


Allison