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Home Forums 68kMLA (Question) 1990 Maxtor Terminator Resistors — #9
Post #9 by trag
Source Forum68kMLA
CategoryHardware
Post DateWed, 14 Jan 2015 - 18:36
Original URLhttps://68kmla.org/bb/threads/question-1990-maxtor-terminator-resistors.1040/
Post
Yes.  The guy I had been talking to sent me a similar diagram.  He had suggested the 220/330 setup also.

Here's a picture; it's most definitely 11 pins.  There are, indeed, two resistors.  Unfortunately, trag, I couldn't find the topic, searching for 'bourne 4610.'  I apologize if this is rehashing.

The question then is bussed or isolated?  I get the difference conceptually now, I just don't know what if any standard existed or how the difference would affect this setup.  My thought is bussed; but I am very open to any thoughts on that. 
To be more certain, I would get out an ohmmeter and see if there's continuity between pin 1 of the connector on the hard drive for each pack and the ground pin on the power supply and pin 11 of each pack and the 5V pin on the power supply input.   The only caveat being that there might be a 5V regulator or some such on the hard drive between the termination pack 5V pin and the input power supply pin.

Actually, just finding that the pin 1s and pin 11s are common between the two termination pack connectors is probably dispositive.

If the resistor packs are 220/330 networks then pin 1 will be GND and pin 11 will be +5V.    If they're bussed or individual resistors, then the pin arrangement will be different.  A bussed resistor arrangement would have only one pin of each connector common.   An isolated resistor arrangment should have none of the pins common, or maybe every other pin common.

If they're 220/330 resistor networks, then you want bourns 4611X-104-221/331 or Bourns 4311R-104-221/331.  The only difference between them is the packaging.

mp.ls