Designing a TRULY PORTABLE TI-99/4A

[TheMole]

Might cable length be the issue? My console-to-card cable is about 15 inches in length.

 

( straw I haven't yet grasped ).

 

Have you tried looking at the contents of one of those formatted disks that threw error 38 in a working system yet? Perhaps with a sector editor or some such? Maybe you can find something that points you in the right direction. Error 38 would seem to indicate some unknown error while reading, so it might be that the disk actually does get formatted but something goes wrong during the validation step (if that even exists)?

[Gazoo]

 

Sounds a similar length to my cable.

 

So formatting a disk with Disk Manager gives error 38? Is that actually a valid error number? What happens if you try to do a simple SAVE from BASIC to a formatted disk?

 

 

 

Have you tried looking at the contents of one of those formatted disks that threw error 38 in a working system yet? Perhaps with a sector editor or some such? Maybe you can find something that points you in the right direction. Error 38 would seem to indicate some unknown error while reading, so it might be that the disk actually does get formatted but something goes wrong during the validation step (if that even exists)?

 

 

Interesting results from these 2 tests.

 

Attempting to save a Basic program results in an I/O error 66.

 

Looking at the disk where the format process failed, sector 0 has been written correctly. However, sector 1 is not zeroed out as would normally be the case.

 

 

Gazoo

[+InsaneMultitasker]

Does the flex cable interface pull any of the signals high or low that the extension cable does not account for?

 

Seems to me the basic data and addressing are "working" in both directions, otherwise you would never get beyond the powerup nor could you read a disk directory.

 

Of course, it could be some signal degredation a continuity test would not identify. Or.. the gremlins from the annual Chicago Faire have made their way into your work area.

 

Have you tried a faster controller, i.e., a Myarc or SCSI card, to get a sense of tolerance?

[Gazoo]

http://www.avjd51.dsl.pipex.com/ti/ti.htm

 

According to the description on Stuart's page linked to above, there are 4 pullup resistors to 5v.

I have these installed and connected to the +5v source. Per the description, one side of the

resistor is connected to +5v and the other side to the indicated pin, correct?

 

I haven't tried a different card because I'm not sure if they would be compatible with the cable.

The cable is designed to be used with a TI controller, not all lines are connected. I was hoping

not to damage any of my other cards. Unless, of course, the Insane Multitasker repair service is

prepared to do repairs gratis.

 

Gazoo

[+InsaneMultitasker]

I see a total of five pullups in the drawing. AMA,B,C, SENIL, and PCBEN. Were you watching the ST:TNG episode where a tortured Picard only sees only 4 lights?

[Gazoo]

Yeah, there's 5. I had a brain fart (or maybe it wasn't my brain, maybe Spock's brain?), my cable has all of them. Radioshack sells them in packs of 5 & I used them all.

 

Was that an episode with the Romulans? With this right knee of mine I always feel like a tortured Picard.

[Opry99er]

Ahh yes....