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fjk61011
July 22nd, 2017, 08:52 AM
I am fairly certain I have an ST-412 Hard Drive with the Termination Resistor and a Shunt.

I have a control cable with connectors for two drives. Which should I use for the Single drive.?

Chuck(G)
July 22nd, 2017, 09:25 AM
Position 8 on the shunt should be closed (radial select).

Whether you select position 1 or 2 on the shunt for drive select (some people just insert an 8 position DIP switch) depends on the cable. If you have a cable with a twist in it before the end connector, then short position 2 (Drive select 2); if it's a flat cable, or if you're using the drive connector nearest the controller, set shunt position 1 (drive select 1). If this is your only drive, it will do no harm to set both positions 1 and 2. The signal cable connects to the appropriate connector on the controller; generally, the lower numbered connector (e.g. they're labeled J3 and J4) corresponds to the first drive.

Your ST412 should spin up with only the power connected (i.e. no other cables used).

fjk61011
July 22nd, 2017, 09:37 AM
Position 8 on the shunt should be closed (radial select).

Whether you select position 1 or 2 on the shunt for drive select (some people just insert an 8 position DIP switch) depends on the cable. If you have a cable with a twist in it before the end connector, then short position 2 (Drive select 2); if it's a flat cable, or if you're using the drive connector nearest the controller, set shunt position 1 (drive select 1). If this is your only drive, it will do no harm to set both positions 1 and 2. The signal cable connects to the appropriate connector on the controller; generally, the lower numbered connector (e.g. they're labeled J3 and J4) corresponds to the first drive.

Your ST412 should spin up with only the power connected (i.e. no other cables used).

OK, I'll try that later.

The drive came with the 5161 and looks brand new. I tried to get it working in the 5150 but I was getting conflicts with the VGA card. I forget which way it was cabled in the Expansion Unit but think it was the middle cable.

fjk61011
July 22nd, 2017, 10:38 AM
Position 8 on the shunt should be closed (radial select).

Whether you select position 1 or 2 on the shunt for drive select (some people just insert an 8 position DIP switch) depends on the cable. If you have a cable with a twist in it before the end connector, then short position 2 (Drive select 2); if it's a flat cable, or if you're using the drive connector nearest the controller, set shunt position 1 (drive select 1). If this is your only drive, it will do no harm to set both positions 1 and 2. The signal cable connects to the appropriate connector on the controller; generally, the lower numbered connector (e.g. they're labeled J3 and J4) corresponds to the first drive.

Your ST412 should spin up with only the power connected (i.e. no other cables used).

It is an ST-412 drive. The cables more or less line up with the drive with "folds" in the cable. The shunt has 7 metal pieces shaped like an hour glass. From the connector end of the drive: 1 is a complete hour glass, 2,3, 4 half an hour glass. 5,6,7 full hour glass. Is that short, open, open, open, short, short, short?

fjk61011
July 22nd, 2017, 11:10 AM
http://bitsavers.trailing-edge.com/pdf/seagate/ST412_OEMmanual_Apr82.pdf

This document says the shunt is a 14 pin unit plugged into a 16 pin socket leaving pins 1 and 16 empty. thats's the same as my setup.

http://www.minuszerodegrees.net/misc/st412_tres_shunt.JPG

Same setup as here.

Chuck(G)
July 22nd, 2017, 11:12 AM
I don't know from "hourglass". However, I did make an error (though it won't matter in a single drive situation)--you don't want "Radial select".

At any rate ST412 OEM manual (http://bitsavers.informatik.uni-stuttgart.de/pdf/seagate/ST412_OEMmanual_Apr82.pdf) (Consult figure 13, PDF page 30).

States that you have 14 pin shunt block plugged into a 16-pin socket, with pins 1-16 left unconnected. But my comments on DS1 and DS2 still obtain. Note that "H" and "D" are not options on the ST412.

Edit I see you found the manual as I was typing this message.

fjk61011
July 22nd, 2017, 12:15 PM
I don't know from "hourglass". However, I did make an error (though it won't matter in a single drive situation)--you don't want "Radial select".

At any rate ST412 OEM manual (http://bitsavers.informatik.uni-stuttgart.de/pdf/seagate/ST412_OEMmanual_Apr82.pdf) (Consult figure 13, PDF page 30).

States that you have 14 pin shunt block plugged into a 16-pin socket, with pins 1-16 left unconnected. But my comments on DS1 and DS2 still obtain. Note that "H" and "D" are not options on the ST412.

Edit I see you found the manual as I was typing this message.

I left the drive as it was set and connected it to the centre connector. Installed MS-DOS 5.00 and mTCP. Working well.