18 Sep
2006
18 Sep
'06
4:16 p.m.
On 9/18/2006 at 11:07 PM ard at p850ug1.demon.co.uk wrote:
I don't recall there being any custom parts. All
standard DIL ICs (VCO,
phase detector circuit, etc). If anyone wants me to check, I have the
card, and I have the techref (I have found times when the IBM card and
the Techref don't agreee :-)).
Mine is in front of me: 2/3 length card, with what appear to be 3 hybrid
thick-film packages at the lower left. The largest is labeled "5564252/IBM
22 1/1 8147 3719" and is about an inch square. There are two smaller
(about half-inch square) packages adjacent to it. Date codes on the TTL
are in the second half of 1981--and I assume that the "8147" on the third
line of the big hybrid is also a date code.
Could it be that export 5150s used a different setup?
Rememebr the data rate of 8" SD is the same as
that of 5.25" DD. I have
an idea the data separate _will_ lock to 8" SD (which is still 250kbps),
and you can then program the FDC chip to do single density operations. I
have never tried this, though.
Tried it myself years ago. Didn't work with my FDC.
Cheers,
Chuck