2 Nov
2010
2 Nov
'10
1:30 p.m.
Cheers for the link. Now I just need to fix the PCB on
the 231 (some
idiot has gone and ripped a few tracks and pads off the board) and steal
some parts (a PCB mounting screw!) from the 156...
Is there soemthing special about the screw? Why do you need to take it
from another drirve?
Given its wiring, I suspect SW1 is the drive select switch (it isn't
fitted on either of my drives). What I don't get is why it's got three
pins plus common. Common goes to the "SELECT" input on the controller
chip, 1 goes to /SEL1 (pin 4), 2 apparently goes to /SEL0, and 3 carries
the READY signal from the drive (?!). JP1 allows SEL0 and SELECT to be
bridged without the switch present.
The only way this would make sense is if switch pin 3 was open-circuit...
The schematic I have to hand shows SW1 as switching bwtween drive select
0 (pin 4 of the connecotr) and drive sleect 1 (pin 6 of the connector.
The common connection goes to the D-SELCT/ input of the main ASIC. There
is indeed a jumper to connect up Drive Select 0 if the switch isn't fitted.
Alas the manual doesn't show PCB layouts, just a schematic So I have no
idea if there's an exta non-connected pin on the switch.
-tony