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Dutchman2000

PEB disk drive set as DSK2. needs to be DSK1

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I just acquired a PEB with an IBM 360k DSDD drive in it.  When I go to use the drive, it only works as DSK2.  I can't use any of the booting disk games since they only work with DSK1.  I've looked at the drive and I cannot find a setting that would change the drive select to 1 instead of 2.

 

Here is a picture of the drive's logic board, I don't see a terminator or a jumper select.  Any ideas?

IMG_8685.jpg

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I just acquired a PEB with an IBM 360k DSDD drive in it.  When I go to use the drive, it only works as DSK2.  I can't use any of the booting disk games since they only work with DSK1.  I've looked at the drive and I cannot find a setting that would change the drive select to 1 instead of 2.
 
Here is a picture of the drive's logic board, I don't see a terminator or a jumper select.  Any ideas?
IMG_8685.thumb.jpg.401110ff0c343fb7b857f239d8df2868.jpg
The yellow chip is the terminator
Can you post the make and model of the drive

Sent from my LM-V600 using Tapatalk

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11 minutes ago, arcadeshopper said:

The yellow chip is the terminator
Can you post the make and model of the drive

Sent from my LM-V600 using Tapatalk
 

Sure IBM 0384-002

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Looks like this is missing the shunt pack location so the only way to select drive is with cable either will have to modify your cable or use a shift 838 drive select board I found information on this drive with a Google search showing that is made by teac but the board in the manual has an extra location that I don't see on yours

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1 minute ago, arcadeshopper said:

Looks like this is missing the shunt pack location so the only way to select drive is with cable either will have to modify your cable or use a shift 838 drive select board I found information on this drive with a Google search showing that is made by teac but the board in the manual has an extra location that I don't see on yours

Sent from my LM-V600 using Tapatalk
 

I found that manual as well, the board does NOT match the diagram in several ways.  I think this is a different board. 

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I found that manual as well, the board does NOT match the diagram in several ways.  I think this is a different board. 
IBM is notorious for building drives that only fit their use case

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I think the key here is that yellow chip.  I'm going to remove it and see if there is any labeling underneath.  Also see if it works with it removed. 

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That space to the right of the resistor pack labelled "S1 (Opt)" may be the space for an optional switch pack. Is that component across it just a zero ohm resistor that selects DSK2 as the default when the switch pack is not installed? If you get the pinout for the floppy connector (it's standard) and have a multimeter, you could check if that resistor is connected to one of the drive select connector pins, which will give you a clue as to how to tweak the connection to change it to DSK0.

Edited by Stuart
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2 hours ago, Stuart said:

That space to the right of the resistor pack labelled "S1 (Opt)" may be the space for an optional switch pack. Is that component across it just a zero ohm resistor that selects DSK2 as the default when the switch pack is not installed? If you get the pinout for the floppy connector (it's standard) and have a multimeter, you could check if that resistor is connected to one of the drive select connector pins, which will give you a clue as to how to tweak the connection to change it to DSK0.

This is where I was going too. That looks like the spot where the drive selection circuitry would be set up--and that single resistor is most likely giving you your selection to drive 2. If that is the case, moving the end closest to the connector to the position immediately to its left or right (as looking towards the 34-pin connector) may put you into a drive 1 selection--but you will definitely need to ohm that out first. Also note that it is connected to a pad outside the footprint of the switch at one end--that position may also be important.

 

I just pulled up a copy of the TM-100-2 manual to look at it. The shunt is placed slightly differently on the board in the manual, but the orientation and size are the same. The resistor is connected to the DS1 line (Drive 2). It needs to be connected to the position to the right (looking from the board towards the connector), into the second position from the end (it is in the third position now). You may need to keep the end furthest from the connector in the same position since it is connecting outside the socket, but once again, that would require some signal tracing to see where it goes.

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IIRC, it became the standard for PC drives to be hard-set for DS1 and rely upon the cable twist to set the far-end drive as DS0.  This was common practice before the standard.

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12 hours ago, Ksarul said:

This is where I was going too. That looks like the spot where the drive selection circuitry would be set up--and that single resistor is most likely giving you your selection to drive 2. If that is the case, moving the end closest to the connector to the position immediately to its left or right (as looking towards the 34-pin connector) may put you into a drive 1 selection--but you will definitely need to ohm that out first. Also note that it is connected to a pad outside the footprint of the switch at one end--that position may also be important.

 

I just pulled up a copy of the TM-100-2 manual to look at it. The shunt is placed slightly differently on the board in the manual, but the orientation and size are the same. The resistor is connected to the DS1 line (Drive 2). It needs to be connected to the position to the right (looking from the board towards the connector), into the second position from the end (it is in the third position now). You may need to keep the end furthest from the connector in the same position since it is connecting outside the socket, but once again, that would require some signal tracing to see where it goes.

THAT WORKED!!!  It is now DSK1!!   Thanks to everyone who helped!

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Good to hear that! :-D I'm working on a partially functioning MFM hard drive myself right now; one thing is certain: these things don't get more stable with age, unlike us... ha ha

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55 minutes ago, arcadeshopper said:

photo?

It's back in the PEB to stay for now......

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