30 Jun
2009
30 Jun
'09
11:37 a.m.
Tony,
Here is my list of what it isn't ;
Thanks... After reading the databook that Al kindly scnaned and put on
Bitsavers, I came to the same conclusion. It's none of the obvious devices.
I now know a little more about it -- it's the data encoder/decoder, and
it may also do things like sector mark detection. Pin 4 is the encoded
write data output, which goes to an external delay line. The taps on the
delay line are selected by a '151 multiplexer, the control inputs on that
come from pins 1-3 on this unknown IC. Presumably write precompensation.
Output of the mux goes to the HDA connector.
I wodner if it is a custom part...
-tony