New Model II Owner, couple of questions

[hideehoo]

Picked up a well worn example from the original owner (tax preparation) for $100. Came with the unit, expansion chassis with one drive, and about ten disks (including a VisiCalc original). After cleaning out all the mice nests and re-seating of the cards, got it to turn on (yeah!). Next had to scavenge parts from the expansion unit drive to get the main one working, but finally got it boot into TRS-DOS 2.0a (although many of the disks will no longer boot or format, they were Radio Shack branded which I've read aren't the best).

Here's the bad I still need to deal with:

1. The cable on the expansion chassis was cut (?!). I've got a 50 pin ribbon to replace it, but anything special about the rear male connector on the main unit? Looks like a standard unkeyed female IDC connector will fit

2. I'm down a drive door (broken latches, actually found one in the bottom of the case during clean-up) and load pad (again found, but the retention tabs are broke off). The drives are Texas Peripherals, but the load pad looks like the exact same ones used in Shugart SA-800/801 drives. Anyone know of anyplace that would potentially still have parts like these? Barring that, I figure I'll try to model and 3D print a new door latch and just try gluing the old load pad on or try a piece of self adhesive felt cut to the same size.

3. Seems only SS disks work in these? I tried some DS/DD 8" disks I had laying around, but they don't register in the drive. Looking at the sensor for the index hole in the drive, I see what looks like two different sensors offset at the two different index hole positions (obviously drive is SS only with one head).

Already ordered a FDADAP and some NOS 8" floppy to make some more disks. Think a lo-tech IDE adapter may also be in my future.

 

[pski]

Welcome to the frustrating but rewarding Model II club! It looks like you have the rare TPI drives. Does your expansion bay also have TPI drives? I have one in my Model II and have been able to find very little information about it, i.e.. no tech manuals. An old disk drive expert told me it on this forum a while back that it was probably a close Shugart 800 clone although I have not done a thorough comparison. Maybe they were a Tandy cost cutting move? I believe they were added to the Model II only very near the end of it's life so there are very few in existence and parts are probably not obtainable.

The 50pin cable is standard Shugart 8in floppy.

Given that you have a TPI drive I'm sure you have the late FDC card so no need to worry about a terminator on your floppy connector when running without the expansion bay. If your TPI is connected to the FDC card via a connector and not the card edge, then it is the late FDC.

I've also tried DS/DD disks in my TPI and they were rejected which makes sense as they are SS drives.

And I am also setting up a disk imaging machine with an FDADAP here so let's share our progress with that.

Good luck with the beast!

 

[Chromedome45]

Hi and welcome to the big boned TRS-80 club as I call them! I believe the 50 pin IDC was just a straight through 50 pin cable nothing weird. Also find some manuals for the Model II here: http://electrickery.xs4all.nl/comp/trs80m2/doc/ including the technical refernce manual as well. Also be sure to check the Model II technical bulletins. They list the hardware mods the service centers did to the Model II's. See if yours has them installed. Good luck

 

[JonB]

Welcome from me, too.

Model IIs are wonderful old dinosaurs. Real computers, as I like to call them. Whir whir click whir CLUNK! That's a pretty good haul you have there.

I've a few answers for you.

I used Blu-tack (do you have it in the U.S.?) to reattach the pad to the arm inside the drive (Shugart). Not had a problem yet. I also took the drive apart and applied light oil to all the moving parts where lubrication looks necessary.

External drive connector is as you say, unkeyed 50pin IDC. Pin to pin, nothing fancy. Must be terminated with the Tandy terminator if you aren't using the expansion box (this is a small widget that plugs into the external socket at the back of the Model II).

Consider replacing the filter caps in the power supply, they are getting old and will fail at some point (spectacularly, with lots of smelly white smoke). You could get a new power supply altogether. One of our members replaced it with a switching supply (to fix the screen wobble when the drive is accessed due to the standard supply being a bit weak). I think he also swapped out the noisy fan for a modern quiet one.

Yes it is SS. You can use a DS disk by punching a hole in it at the correct place. Use the sleeve from a dead SS disk as a template, mark with a pencil and punch it out with a hand held punch. Easily bought from eBay.

Operating systems available include TRSDOS, LSDOS, CP/M (at least two flavours), but getting downloaded disk images onto an 8" floppy can be tricky. Fortunately there are quite a few resources to help you, have a look around...

To use a LoTech IDE adapter you need the Hans01 card (itself an adapter of sorts), which is in beta test. I'm not sure they are generally available yet. Forum member TRS-Ian has them. Only LSDOS is supported at the moment. For other OSes, drivers need to be written.

Hopefully all your keys work. They commonly fail but are easy to fix, if a little time consuming. Once again, TRS-Ian has an answer (he did a "how to" video which you can see on his web site here http://ianmav.customer.netspace.net.au/trs80/).

It's great to see another Model II in the hands of an enthusiast. These grand old machines have been unloved and neglected for so long! Even the main TRS-80 sites seem to ignore them. There's lots of information on the Model I, III and IV but remarkably little about the II. I hope we can put that right.

Regards
JonB

 

[NF6X]

Another vote from me on replacing the EMI filter caps immediately before they catch on fire. They are the rectangular, translucent yellow ones made by Rifa. The cases will almost certainly be visibly cracked, letting moisture into the paper dielectric. Replace with equivalent poly film safety-rated caps. Let me know if you need help identifying suitable part numbers. After having one light up inside my Model 12, I now replace them on sight before even trying to apply power.

Hopefully the keyboard will work, but there's a good chance you'll need to replace decomposed foam pads in the keys to get it working. Just part of the fun of being a Model II owner!

 

[Hans01]

Welcome from me too.

Consider replacing the filter caps in the power supply, they are getting old and will fail at some point (spectacularly, with lots of smelly white smoke). You could get a new power supply altogether. One of our members replaced it with a switching supply (to fix the screen wobble when the drive is accessed due to the standard supply being a bit weak). I think he also swapped out the noisy fan for a modern quiet one.

Yes, that was me, look at my older postings.

Yes it is SS. You can use a DS disk by punching a hole in it at the correct place. Use the sleeve from a dead SS disk as a template, mark with a pencil and punch it out with a hand held punch. Easily bought from eBay.

Be careful with this modified disk. Cover the old index holes on both sides with a piece of black tape. I use themal labels and I made them black with
a solder iron, the index led shines easy through white paper. If you left the old index holes open, a DS drive will see it as DS disk and try to write
on the backside. I have ruiend a lot of data before I understood what was wrong.

To use a LoTech IDE adapter you need the hans01 card (itself an adapter of sorts), which is in beta test. I'm not sure they are generally available yet. Forum member TRS-Ian has them. Only LSDOS is supported at the moment. For other OSes, drivers need to be written.

Yes, the hans-01 is ready to use and is available at Ian's. There are empty PCB's and populated ones. You need a Lo-Tech ide controller to complete
the set. The empty PCB's can be ordered at James for a special price until the 30th of august.