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full height 360k floppy drives

oblivion

oblivion

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okay, this is probably a really dumb question but...did the original full height 360k floppy drives get power via the floppy cable? I ask because I have one which I'm trying to use with a 5150 I'm restoring and I cant find a connector for the power supply anywhere on the thing. If I just hook it up to the controller nothing happens. no lights, no drive seeking, nothing. the controller did work fine with a 720k drive using the trick of flipping the floppy cable backwards but I cant get the original full height drive to come alive. I'm left wondering if the drive is just dead or its just not getting power because for the life of me I don't see a connector for power on it.
 
I think all the full height floppy drives used a 4 pin AMP. I looked at the Tandon manual and the power connector seems to be located on the right side and just below the row of cables. The old connector may have been ripped off (weak solder links versus strain as power cable is forced off) so look for a set of 4 solder points all in a close set row. Pain reattaching a connector to the solder points.

What model floppy is it? What model computer?
 
Last edited:
oblivion said:
okay, this is probably a really dumb question but...did the original full height 360k floppy drives get power via the floppy cable?
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That's not a possibility as the 34 conductor floppy ribbon cable does not carry either 5V or 12V on it. FWIW, neither does the 34 conductor hard drive control cable nor the 20 conductor hard drive data cable.
 
now that I look at this drive I don't even know if its ment for the IBM, it simply came with the lot that I got. I don't see anywhere on it a psu connector may of gone that broke off either.

the drive is a MPI MODEL 51
mfg JULY 1982
 
The MPI should have a 4 pin Molex style connector mounted on the bottom of the circuit board. A manual is at http://www.osiweb.org/manuals/MPI_B51-B52_Product_Manual_Long.pdf with the location for the power connector shown in Figure 2-1. Unfortunately, the image is done from the side and there does not seem to be a close up of the back so you can see exactly where all the cables are mounted and easily locate a broken connector.

I can't locate an image of the connectors for the MPI. It looks a lot like the Tandon so I suspect it may just be a rebranded Tandon. But no one seems to take pictures of Tandon's connectors either.
 
The red connector in the second image at the extreme right looks to be for the power going internal to the drive. Take a close look (or picture) of the underside of the board right there. That should be where the mounting for the Molex would normally be. I can't tell for sure because all those wires are in the way.
 
krebizfan said:
The red connector in the second image at the extreme right looks to be for the power going internal to the drive. Take a close look (or picture) of the underside of the board right there. That should be where the mounting for the Molex would normally be. I can't tell for sure because all those wires are in the way.
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5 wires come off the red connector. 1 goes to ground and the other 4 go to what looks to be a spindle motor.
 
oblivion said:
5 wires come off the red connector. 1 goes to ground and the other 4 go to what looks to be a spindle motor.
Click to expand...

That is what I meant: the connector for the power directed to the spindle motor. That connector is on top of the circuit board. Now, look at the bottom of the circuit board right underneath that. There will be 4 pins that normally would have a Molex connector. You will most likely need to solder on a new Molex connector in order to connect the drive to the power supply.
 
From the photos, it should be pretty obvious. The odd-numbered (i.e. "underside) positions on the edge connector form the power connection. A little buzzing out with an ohmmeter/continuity checker will verify this. Normally, odd positions on the signal connector are all at 0V/gnd. This is definitely not the case here.
 
I have. I can't remember where. Tektronix? Wang?

I may have parts from a machine that had drives with only one connector. I have no recollection of what brand it was though. I keep thinking Tektronix but that doesn't seem right.
 
Stone said:
That's not a possibility as the 34 conductor floppy ribbon cable does not carry either 5V or 12V on it. FWIW, neither does the 34 conductor hard drive control cable nor the 20 conductor hard drive data cable.
Click to expand...

Tandy did exactly this on the HX, TX, SL/2, TL's, RL's, RLX's, and RSX's. Teac, Panasonic and Sony made drives for these systems. I've also seen drives like this in dedicated word processors.

The Tandy external primary hard drive units also had 5V (or was it 12v) on the 34 pin cable to turn on a relay in the secondary drives. The primary drives sourced this voltage to the secondary enclosures. When the relay closed the secondary drive would power up. There were no power switches on the secondary units.
 
kb2syd said:
Tandy did exactly this on the HX, TX, SL/2, TL's, RL's, RLX's, and RSX's. Teac, Panasonic and Sony made drives for these systems. I've also seen drives like this in dedicated word processors.
Click to expand...
So this drive is likely not IBM/clone compatible and he's better off finding something else to use.
 
They used this type in the Osborne-1 I believe... I found out when I tried to replace the drive with a PC one.

Osborne-1-FloppyDrive[1].jpg
 
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