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TI Disk drive questions


telengard
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I /finally/ got my hands on a sidecar disk controller and was ready to fire it up and was looking for my TI disk drive. In the past I had sold an PHP1850 and a non cased drive (assumed it was for a PEB). According to my notes I kept 1 single bay cased drive. However, now that I pull it out, I'm not sure it is a TI99/4a drive, and even if it is one, I'm not sure what kind of cable to use. The drive itself has no information at all on the outside (model, serial#, etc). The disk controller seems to have a standard 5.25 edge connector, but this drive has something different (and it looks VERY similar to my Tandy Coco drive).

 

I've attached some pictures. Is this a TI99/4a usable drive?

 

 

 

 

post-7990-0-87999700-1442939194_thumb.jpg

post-7990-0-77903300-1442939216_thumb.jpg

post-7990-0-42833600-1442939262_thumb.jpg

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Hi,

 

I don´t have one of this external drives (PHP1850), nor the external sidecar-controller (PHP1800),

but regarding the controller-manual, it "seems" as if the connector of these external floppydrives, using this sidecar-diskcontroller,

should be the same as used on the internal controller (PHP1240) (except that adapterboard, of course)

so it should be a standard floppydisk-connector 34pin (CE34)

 

post-41141-0-55392200-1442940961_thumb.jpg post-41141-0-13875200-1442940966_thumb.jpg

 

 

So maybe your drive is a different one, with the wrong connector ?

 

 

 

Please also see some pics of my internal drives (PHP1250), I have opened them, maybe that can help a bit...

 

post-41141-0-52564300-1442941248_thumb.jpg post-41141-0-12899700-1442941251_thumb.jpg post-41141-0-76604100-1442941249_thumb.jpg

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Wow, that was fast, thanks! I'll dig out the model # later this evening. @ schmitzi, the pictures sure do look similar. I now need to find a cable to try this out. The back of the disk controller has the key after 4 pins, and the drive is keyed after 2 pins (much like the pictures above). I'd also like to figure out how to connect the PHP1800 controller to my HxC!

Edited by telengard
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yeah

 

Lothareks HxC-drive should work with the same cable, as it is identically to Shugart-drives (means identically to most standard-drives).

But there are many more configs possible on the HxC, but Shugart (non-auto-Mode, Non-Double-Step) is recommended for the TI normally.

 

The floppycable from internal diskcontroller to drives is NOT twisted, and the one RED cable goes to pin #1 on the drive,

but I think you know that. I assume, that it is also NOT twisted with the external drives. Resistor-settings ON for the last drive is important.

 

good luck

 

 

/EDIT/ if in doubt, PIN #1 / RED or BLUE is mostly facing in direction to the drives 4pin-power-connector (molex)

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The drive is from Texas Peripherals. Look at the main casting--it is part of the stamping. They stopped making disk drives around 1985/1986. They use the Shugart standard, so there is no problem using them with the TI. Make sure the drive select is correct on the drive (I forget if they used 0-3 or if it was 1-4 on their drives) Either way, the lowest number is Drive 1 on the TI. There should be a 110 to 330 Ohm resistor pack on the drive too. A good picture of the top of the circuit card will tell me what I need to know there. You may find a manual for it on Bitsavers. . .they have manuals for a lot of different drives.

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If you can find 34 pin floppy cables without the key and just make sure that pin one the red or blue stripe on most ribbon cable faces in the correct direction, the drive will most like work, if it is a working drive or course:) There were also adapters made at the time to use the 4 slot and 2 slot keys together.

I managed to pick up a non-keyed 34 pin card edge IDC cable, just came in today. Now I'm wondering on the PHP 1800 (keyed at 4th position of card edge) and the drive I have (keyed at 2nd position of card edge), which side is pin 1? Is it the side closest to the key?

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There should be one red wire on the cable, which identifies pin 1 on the cable itself. If you look at the edge connector on the drive, you should see a 2 at one end and 34 at the other end (or a 1 and a 33). If you look, you will see that the key is at the end with the 2 (or the 1) visible. You should see similar markings on the edge connector of the Disk Controller, but I suspect it will also be keyed at the same end. . .and mine isn't accessible at the moment, or I would dig it out and check for you.

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Worth noting that if you do plug the cable in round the wrong way, it shouldn't damage anything - the drive will just spin continuously as soon as you apply power.

 

Make sure you do not do this with a disk in the drive. Some drives will activate the write coil and destroy data on that part of the disk. I have, sadly, done this a few times in my career.

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Thanks everyone! Unfortunately, the cable sent (which I had asked to verify had no keying) was keyed at the 2nd finger/pin so I cannot put it in the PHP1800. Having a hard time finding a cable that will fit both devices.

 

You should be able to remove the key with small, needle-nose pliers. The key is usually only held in place by friction. Of course, if the manufacturer actually glued the key into the slot, @sparkdrummer's razor-blade solution is the way to go.

 

...lee

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Most of the keys are held in by pressure against the connector sides, so the needle nose method will almost always remove them. I have "rarely" seen connectors that had the key as part of the original mold. Removing those usually required a really thin bladed flat screwdriver and a light tap with a hammer.Don't do this straight down into the connector--work from the side of the pin, with the screwdriver at an angle and at the top of the blockage first. . .the knife method will usually work too, so this gives you a couple of ways to get rid of that excess pin.

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Thanks for all the ideas!

 

I ended up buying IDC connectors to crimp since I already had an IDC crimper and cable. I made a cable with the twist at one end. Probably should have asked here first before doing that. Do I need to the twist to connect the PHP1800 to the drive, or to the HxC?

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