Floppy drive problems

[lsujim]

I am definitely a NEWBIE related to the TI 99/4A even though it was my first computer in 81. I am trying to set up a working 99/4A with a PEB, original TI monitor, internal PHP-1250, external PHP-1850, 32k RAM card and serial card. I was fortunate enough to find two working PEBs so I could have spare parts. Everything was fully functional until I tried to add an external drive (PHP-1850). I followed the instructions and removed the termination resistor pack on the 1250 (the 1850 has one). I can get both the 1250 and 1850 to light up but I could no longer get the 1250 to autoload the three floppy disks that I have been using (Disk Manager 1.0, Beyond Parsec and Tetris) to test the system. Just goes directly to READY on the monitor. All thee disks worked fine with the extended basic cartridge loaded before I removed the resistor and added the 1850.

I then put the termination resistor pack back on the 1250 and unhooked the 1850. Only the Tetris disk would autoload. Sometimes Tetris loads normally and sometimes it gives me an I/O error 26 in 100 but the other two disks are not recognized and the TI goes straight to READY. Perhaps I damaged the resistor but was very careful. I tried the backup 1250 I have but it has never loaded any of the three programs even though it lights up. I'm not sure why as it is terminated. I know these drives are old and temperamental. I made sure the cable were not twisted and have two of everything but no dice. I also followed other advice that I have seen on the forum (clean all connections, use back up components, move the controller over one slot, etc.) but no luck.I have ordered a disk manager cartridge as it appears essential but am concerned that I do not know how to troubleshoot this issue effectively. My apology if there is an existing thread that I missed. Any advice is greatly appreciated!

Jim

[Charlie_]

 

I am definitely a NEWBIE related to the TI 99/4A even though it was my first computer in 81. I am trying to set up a working 99/4A with a PEB, original TI monitor, internal PHP-1250, external PHP-1850, 32k RAM card and serial card. I was fortunate enough to find two working PEBs so I could have spare parts. Everything was fully functional until I tried to add an external drive (PHP-1850). I followed the instructions and removed the termination resistor pack on the 1250 (the 1850 has one). I can get both the 1250 and 1850 to light up but I could no longer get the 1250 to autoload the three floppy disks that I have been using (Disk Manager 1.0, Beyond Parsec and Tetris) to test the system. Just goes directly to READY on the monitor. All thee disks worked fine with the extended basic cartridge loaded before I removed the resistor and added the 1850.

I then put the termination resistor pack back on the 1250 and unhooked the 1850. Only the Tetris disk would autoload. Sometimes Tetris loads normally and sometimes it gives me an I/O error 26 in 100 but the other two disks are not recognized and the TI goes straight to READY. Perhaps I damaged the resistor but was very careful. I tried the backup 1250 I have but it has never loaded any of the three programs even though it lights up. I'm not sure why as it is terminated. I know these drives are old and temperamental. I made sure the cable were not twisted and have two of everything but no dice. I also followed other advice that I have seen on the forum (clean all connections, use back up components, move the controller over one slot, etc.) but no luck.I have ordered a disk manager cartridge as it appears essential but am concerned that I do not know how to troubleshoot this issue effectively. My apology if there is an existing thread that I missed. Any advice is greatly appreciated!

Jim

 

 

sorry no technical advice, but id clean the drive heads.

[+Schmitzi]

Hi, just some thoughts

 

Wasn´t there a type of "drive select" when using internal and external drives, (jumper or cut-contact on drive), do they differ ?

Maybe try to run each drive alone, to see what happens or where an issue is.

Maybe test it completely without the resistors, worked for me (for a test)

 

Error #26 is something like "drive not ready"

 

Here some more infos from the controllers manual, that helped me from time to time:

 

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[lsujim]

Thanks. I have tried running each separately but no luck. Will rrview the manual again and see if I missed something.

[apersson850]

You're aware of that termination is a physical/electrical thing? It's supposed to be in the drive at the end of the ribbon cable, regardless of how many drives are connected to the cable. If you have two cables, internal and external, then you need two terminators as well.

My TI has four drives. Two connected with the internal cable (these drives are half-height, both located inside the PEB) and two connected via the external ribbon cable. These two are in a separate box.

Drive 2 and 4 have terminators, as they are the last on the internal and external cable, respectively. Drive 1 and 3 don't have any.

Edited January 31, 2019 by apersson850

[lsujim]

Thanks. I guess I need to read more.