About the 80 Track Update for the TI FDC

[atrax27407]

There is an adapter that you can easily make for the TL866 that allows you to program TMS2532s. You piggyback two 24-pin sockets and bend out pins 18, 20, and 21 on the top socket. Connect pin 21 (Vpp) on the top to pin 20 on the bottom. Connect pin 20 on the top (-CE) to pin 18 on the bottom. Connect pin 18 (A11) on the top to pin 21 on thr bottom. Select TMS2732 as your chip and deselect chip ID. Although the voltage is a bit low, it will program the TMS2532s just fine.

[Asmusr]

I'm finally in possession of a pair of 2532s from arcadeshopper, but the thing still doesn't work. I have double checked all soldering and measured pairwise connection between pins on the two sockets with a ohm meter as described here: http://www.mainbyte.com/ti99/upgrade/upgrade.html I have also tested that there are no shorts between neighboring pins. The LED doesn't flash when I turn on the system. I have checked with DU2K that there is no disk DSR. The voltage regulator in the lower right corner is still getting very hot, but there is no indication of damage to any of the components. Any suggestions?

[Shift838]

I'm finally in possession of a pair of 2532s from arcadeshopper, but the thing still doesn't work. I have double checked all soldering and measured pairwise connection between pins on the two sockets with a ohm meter as described here: http://www.mainbyte.com/ti99/upgrade/upgrade.html I have also tested that there are no shorts between neighboring pins. The LED doesn't flash when I turn on the system. I have checked with DU2K that there is no disk DSR. The voltage regulator in the lower right corner is still getting very hot, but there is no indication of damage to any of the components. Any suggestions?

 

i had the same issue on one of my FDC upgrades and it ended up being a bad socket. a specific pin on a socket. I had to jump the pin with a small wire to ensure it was connected to the same pin on the other socket.

 

The pin i had a problem with is in the picture.

 

i would suggest making sure the pins that are supposed to be connected to each other are getting connections with a continuity tester.

Edited October 26, 2016 by Shift838

[Stuart]

Asmusr, on 26 Oct 2016 - 10:29 PM, said:

I'm finally in possession of a pair of 2532s from arcadeshopper, but the thing still doesn't work. I have double checked all soldering and measured pairwise connection between pins on the two sockets with a ohm meter as described here: http://www.mainbyte.com/ti99/upgrade/upgrade.html I have also tested that there are no shorts between neighboring pins. The LED doesn't flash when I turn on the system. I have checked with DU2K that there is no disk DSR. The voltage regulator in the lower right corner is still getting very hot, but there is no indication of damage to any of the components. Any suggestions?

 

If you've got a Minimem cartridge you can use EasyBug to enable the FDC card and check the DSR. Select EasyBug from the title menu screen then at the '?' prompt type C1100<Return>1<Return>(LED on card should now be on)<full stop>M4000<Return><Space><Space><Space><Space><Space><Space>... should read out the start of the DSR as >AA, >02, >00, >00, >40, >44 ,,, Do you get that?

[+arcadeshopper]

I'm finally in possession of a pair of 2532s from arcadeshopper, but the thing still doesn't work. I have double checked all soldering and measured pairwise connection between pins on the two sockets with a ohm meter as described here: http://www.mainbyte.com/ti99/upgrade/upgrade.html I have also tested that there are no shorts between neighboring pins. The LED doesn't flash when I turn on the system. I have checked with DU2K that there is no disk DSR. The voltage regulator in the lower right corner is still getting very hot, but there is no indication of damage to any of the components. Any suggestions?

 

I had the same problem, turned out to be solder under the socket. I had to send it to Jim and he got out his giant magnifying something or other and found the shorts.. I had tested with an ohm meter for shorts and they all passed but he found some that were so tiny I guess they didn't make enough of a connection to trigger the meter's beep, but enough to screw up the DSR.

 

Greg

[Asmusr]

I would suggest making sure the pins that are supposed to be connected to each other are getting connections with a continuity tester.

 

Thanks, but I already did that.

[Asmusr]

 

If you've got a Minimem cartridge you can use EasyBug to enable the FDC card and check the DSR. Select EasyBug from the title menu screen then at the '?' prompt type C1100<Return>1<Return>(LED on card should now be on)<full stop>M4000<Return><Space><Space><Space><Space><Space><Space>... should read out the start of the DSR as >AA, >02, >00, >00, >40, >44 ,,, Do you get that?

 

Thanks, I used the option in DU2K to look for DSR headers and it isn't there.

[Asmusr]

I guess I will try to reheat the solder or each pin and check the connections again. If that doesn't help I might build the adapter that atrax suggested so I can test the EPROMs.

[Stuart]

 

Thanks, I used the option in DU2K to look for DSR headers and it isn't there.

 

I'm not familiar with DU2K - does it just report whether there is a valid FDC header? Testing using the MiniMem will (a) test whether the card can be enabled (LED lights) and (b) shows you what (if any) data is being read from the DSR space - irrespective of whether that data represents a valid DSR header or not. If you can read data from the DSR space but it is not the correct data, that might help track down the problem, like a shorted data line.

[Asmusr]

 

I'm not familiar with DU2K - does it just report whether there is a valid FDC header? Testing using the MiniMem will (a) test whether the card can be enabled (LED lights) and (b) shows you what (if any) data is being read from the DSR space - irrespective of whether that data represents a valid DSR header or not. If you can read data from the DSR space but it is not the correct data, that might help track down the problem, like a shorted data line.

 

Thanks. I see. I will check tonight.

[Asmusr]

 

If you've got a Minimem cartridge you can use EasyBug to enable the FDC card and check the DSR. Select EasyBug from the title menu screen then at the '?' prompt type C1100<Return>1<Return>(LED on card should now be on)<full stop>M4000<Return><Space><Space><Space><Space><Space><Space>... should read out the start of the DSR as >AA, >02, >00, >00, >40, >44 ,,, Do you get that?

 

I'm getting >BA, >12, >00, >00, >40, >44, >00, >00, >40, >5A ... Looks like a problem with bit value >10?

[Stuart]

So from that data it looks like a short between the two bits marked with an X: – – – X – – X –? Trying checking at the EPROM sockets for a dead short between each data pin and each of the other data pins. Possibly a short from a pin to a trace running next to it under the socket. (If you end up removing then refitting the sockets to cure the problem, see if you can raise them up a millimetre or two so you can see below the socket body where the traces go between the pins.)

Edited October 27, 2016 by Stuart

[Asmusr]

So from that data it looks like a short between the two bits marked with an X: – – – X – – X –? Trying checking at the EPROM sockets for a dead short between each data pin and each of the other data pins. Possibly a short from a pin to a trace running next to it under the socket. (If you end up removing then refitting the sockets to cure the problem, see if you can raise them up a millimetre or two so you can see below the socket body where the traces go between the pins.)

 

Yes, that was it, exactly as you said. It almost killed the card that I had to remove one on the sockets again, the copper traces were starting to fall off, but miraculously there was no lethal damage. Thank you so much for your help.

[+Ksarul]

The traces on the FDC from TI are really tight when it comes to clear spaces between the traces and the pads. It was a real beast finding the tiny shorts (and breaks) on the card Arcadeshopper sent me, but once I cleaned everything up, it worked like a champ.

[+helocast]

Thanks to everybody's help in this thread, I also found adjacent pins shorted (highlighted in photos).

I was careful to check same pin on each socket for continuity per mod instructions, but never occurred to me to check adjacent pins for continuity in the SAME socket =]

[+Ksarul]

I would suggest giving the solder joints there a good cleaning with some denatured alcohol and then look the spaces between the pads over with a nice 3-5 power magnifying glass. Some of them look like they might have partial solder bridges. . .

[rgjt]

I tried this modification and it does work very well. Be careful in removing the existing ROM chips as the traces are quite close. I did not have the proper equipment to do it so I brought it to a local electronic repair shop. They desoldered the ROMS without any damage, soldered the sockets in less than hour. I used the 80 track eprom for DSK2 and DSK3 and 40 track eprom for DSK1 since I have a 3.5" diskette as DSK2.

It works great formatting the 3.5" drive using either 40 or 80 tracks.

One thing to bear in mind that you must use Disk Manager 2 to format to 80 tracks or Fred's DM2K. 

DM1000 will not work as it's limited to 40 tracks.

I will now try the other set of eproms that will allow 80 tracks on my doble sided DSK1 5.25" floppy drive that already supports 80 tracks.

This will make it easier to copy between the 3.5" and the 5.25" drives.

This project is a great addon to the PEB FDC. Not sure why pushed the 40 track system to begin with.

[SkyPilot]

Interesting thread, before TIPI.

[+OLD CS1]

38 minutes ago, SkyPilot said:

Interesting thread, before TIPI.

Also interesting for any number of people who do not have the x-level technology which post-dates floppy disks.

[+dhe]

I have considered this...

 

I pretty much use gotek's exclusively. My thought process was, even if I could not find another DS/DD disk controller, I could drop this in, and have the same amount of storage, so it would make it easy to move a DS/DD dsk image, to an image and use the TI controller.

 

I also have like 5 TI Controllers, and it wouldn't hurt much if I killed one doing the upgrade/conversion...

 

 

[+OLD CS1]

3 hours ago, dhe said:

I also have like 5 TI Controllers, and it wouldn't hurt much if I killed one doing the upgrade/conversion...

I could not help but to think of choosing which of my five kids I am going to test experimental upgrades on.

 

You know, I have one of those Goteks laying around here.  Got it in a grab-bag of stuff I picked up a while back.  I still cannot get myself off the floppies.  I might need an intervention.

[+dhe]

For anyone gnu here, another worth while mod is the John Guion upgrade for TI's standard DSR.

[atrax27407]

I can supply either of the upgrades. The current price is $14 for the two-chip set.

[+arcadeshopper]

I can do the mods for people.. it's in my store if you want to supply your own controller that's an option. I also can offer trade-in credit for TI controllers if you have some lieing around you don't need. 

 

https://www.arcadeshopper.com/wp/store/#!/80-track-upgrade-for-Texas-Instruments-Floppy-Disk-Controler-PEB-card/p/451889376/category=0

 

Greg