24 Nov
2005
24 Nov
'05
8:45 p.m.
On 11/23/2005 at 8:01 PM ard at p850ug1.demon.co.uk wrote:
Thanks for that. It seems to make sense against the PCB I'm investigating...
Does anyone have the pinout (or a datasheet) for
the SED9421 chip (18 pin
DIL package).
I found this on a Japanese site:
1.XG
2.XD
3. ph1
4.NC
5.RD DATA
6.WINDOWS
7.DATA
8.MFM/FM
9.MIN/STD
10.VSS
11.CONTROL
12.OFFSET
13.LPF
14.WCLK
15.ph2
16.NC
17.NC
18.VDD
It appears to be a VFO for use with the SED9420C data separator (like you'd
find in an Amstrad CPC).
I never thought to look in Amstrad service manuals (and I have quite a
number of them). They sed the SED9420 quite a lot (in the CPC, PCW, etc),
but never with an external VCO.
Are you sure the SED9421 is not a complete data seperator? The PCB I am
looking at (from an Epson PF10 drive unit) doesn't seem to have much else
around the 765 disk controller chip.
-tony