resistor packs for terminating SCSI bus inside Exabyte 8020
glen.slick at gmail.com
Sat Feb 6 19:51:44 CST 2021
On Sat, Feb 6, 2021 at 4:33 PM Nigel Johnson via cctalk
<cctalk at classiccmp.org> wrote:
> I have some 4608X-104-221/331L currently in my digikey shopping basket -
> I will place order on Monday after I confirm that the two outside pins
> go to Vcc and Fss and the six others go to signal pins on the bus.
I pulled the SIP packs out of my EXB-8200 because it is mounted in an
external case and the next time I go to use it I would probably attach
an external terminator to it without thinking that it was terminated
I measured ~91-Ohm between pin 1 and pin 8, which is the expected
value for (6x) (220-Ohm + 330-Ohm) in parallel.
I measured ~163-Ohm between pin 1 and each of pin 2, 3, 4, 5, 6, 7.
That is the expected value for 330-Ohm in parallel with (220-Ohm in
series with 110-Ohm ((5x) (220-Ohm + 330-Ohm) in parallel).
I measured ~145-Ohm between pin 8 and each of 2, 3, 4, 5, 6, 7. That
is the expected value for 220-Ohm in parallel with (330-Ohm in series
with 110-Ohm ((5x) (220-Ohm + 330-Ohm) in parallel).
So a 4608X-104-221/331L should be a functional equivalent (220-Ohm in
common to pin 8, 330-Ohm in common to pin 1).
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