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Nondescript Tandy 6000 problem

A

alnwlsn

New Member
Joined
Feb 10, 2019
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Any 8" machine experts around? I am trying to bring up a 6000 and have some sort of error when trying to install Xenix. Here's where I am so far:
  • cleaned out dust (good lord was it ever dusty!)
  • replaced filter caps and some leaky electrolytics
  • cleaned floppy disk drive
  • got one of the diagnostic disks from Ebay; it booted
  • got impatient waiting for new foam and foil pads to get here; made own PS2 keyboard adapter
  • also made an adapter to use a Gotek with FlashFloppy since I have no other 8" floppy hardware. Worked; was able to copy a TRSDOS disk onto a couple of real floppies and boot off it (the disks and the Gotek)
  • thought I might have had a bad hard disk controller...
    • Type 4, PP-2 board from what I can tell
    • HDREL diagnostic gave only ID Not Found errors
    • Decided to try Controller Alignment procedure on pg. 223 of Service Manual
      • it fixed it! it now passes HDREL write/read test
      • I think it was mostly the R2 adjustment
      • side note: I could not get a DLYDATA pulse within the 70-80nsec specified, I could only get to 84ns. I noticed my controller chip has a WD1100-21 for U27 instead of the WD1100-11 on the schematic. I found a datasheet for that chip in this catalog, and it suggests a nominal RD pulse of 90ns. Not too familiar with Winchester drives, so I don't really know what this means.
  • put 68000 board and ram board back in, tried the 68000 diagnostics, seemed to pass
  • get ready to install Xenix - get the disk images, put on Gotek, and try to format the hard drive with diskutil
Here's where I run into problems. When I try to run diskutil at the Xenix Boot prompt after booting from the install floppy, I get "Bughlt: HRDIOE - Can't load Xenix" I can only assume this means "Hardware IO Error" I tried XNX300D1.IMD and XNX320D1.IMD, and both had the same error. When I tried the older Xenix (XNX110D1.IMD), I simply get "I/O error loading XENIX" It does this regardless of what hard drive I have connected (either the original Tandon drive or the handful of 10mb MFM drives I tried it on). "IO error" is not very descriptive.

The thing is, when I connect the hard drive that came with the machine, it actually boots off it - it did not boot until after I did the controller alignment. It gets all the way to the login prompt, but not knowing any passwords I did not log in. I want to set this drive aside until I know the rest of the machine is working properly (and after I read up on Xenix, I really have no idea how to use it yet)

I tried some of the other diagnostics on the diagnostic floppy, and the only ones I noticed so far that did not pass were within the Model II tests: the PIO test (which says I need a ?loopback? connector), and the interrupt test (image attached), but I do not know what tests are supposed to pass/fail on the 6000 vs the other machines. In particular, I read that the memory test on the type 4 HDC boards does not pass with the diagnostics on this disk, even though there's clearly a 2K SRAM on there.

So, anyone have any insight about what might be wrong? Am I missing something super obvious or is this main board in need of some serious troubleshooting?
 

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A bunch of Tandy experts, including people who designed hardware and wrote Xenix drivers for the big Tandys hang out on the Tandy Discord:

Join the Tandy Discord Server!

Check out the Tandy community on Discord - hang out with 275 other members and enjoy free voice and text chat.
discord.gg discord.gg
 
That's a good call; independently discovered the Tandy server today and have been checking it out - seems to be pretty active.
 
To any future adventurers:
Turns out, there was no problem with any of the hardware, my Gotek and breakout adapter were the real problem.
I did not realize that the system cares about what media type is being reported (1 or 2 sides). Whatever type media the original disk was on needs to on 50 pin floppy cable pin #10. If the disk is supposed to be 1 sided, #10 is open. If it's supposed to be 2 sided, #10 should be tied to GND.

This did not become apparent until I wrote a few real disks. Real 2 and 1 sided disks are physically different (index hole in different spot). The first Xenix install disk is supposed to be 1 sided, but when I wrote it on a 2 sided disk, it would fail every time. Using a 1 sided disk worked.

I isolated pin 10 from my 34 to 50 pin adapter, and added a switch to GND. Now, it works with the Gotek too.
 
I am certainly confused about Discord. But I would spend some time to figure it out if there was some valuable content. I tried the link and all I got was a message saying something about logging in from a different location. Why dies that matter? Isn't this supposed to be a mobile app? Confused.

Anyway, welcome to the forum @alnwlsn

Seaken
 
seaken said:
I am certainly confused about Discord. But I would spend some time to figure it out if there was some valuable content. I tried the link and all I got was a message saying something about logging in from a different location. Why dies that matter? Isn't this supposed to be a mobile app? Confused.

Anyway, welcome to the forum @alnwlsn

Seaken
Click to expand...
What's to learn? It's like a bunch of drunken squirrles babbling about where they hid their nuts this year. You'll get some information, but most of it is lost in the noise.
 
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