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TRS-80 model II boot disk

Roland Huisman

Roland Huisman

Veteran Member
Joined
Mar 24, 2011
Messages
1,464
Location
The Netherlands
Hello Everyone,

Today I've picked up some old computer material.

a TRS-80 model II with manual and spare keyboard,
TRS-80 printer (still in the car), Tree 8" drives, a box
of 8" disks and some cabeling. I'd pay 120 euro's because
the TRS was not working. Also the FDD drives are state unknown.
One drive is missing it's PCB. But I still think it is was not too expensive.

TRS80 model II.jpg

But the machine won't boot. It sometimes gives the message:
"Boot error DC" and sometimes "Boot error TK".
So I'm afraid the bootdisk is damaged.

Can anyone help me get such a disk?

Thanks in Advance!

Regards, Roland
 
Hello patscc,

Yes I did and also replaced some caps.
But I can not check if it's the drive
or the bootdisk at this moment.

Regards, Roland
 
Roland Huisman said:
Hello patscc,

Yes I did and also replaced some caps.
But I can not check if it's the drive
or the bootdisk at this moment.


Regards, Roland
Click to expand...

Roland:

Back in the day when I actually used the Model II at my work place (early 80's), we were constantly having to create boot disks. The reason was if the user left the diskette in the PC, or extension bay drives, it would get zapped when you powered the system down. You had to make sure to remove the disk prior to shutting down. Also, you need to check the felt tension pad(s) on you drive(s). They are about the size of a pencil eraser and can kill a diskette real fast if let to wear down. You can Google for the software - there's plenty of user forums out there. Good luck.
 
"If the user left the diskette in the PC, or extension bay
drives, it would get zapped when you powered the system down"
Click to expand...

Wow, this sounds like a serious design fault...
Were they magnetic destroyed and could they be reformatted?
Or were the disks mechanically damaged?

Regards, Roland
 
Roland Huisman said:
Wow, this sounds like a serious design fault...
Were they magnetic destroyed and could they be reformatted?
Or were the disks mechanically damaged?

Regards, Roland
Click to expand...

If I remember correcly, only the boot track was zapped, and there was no physical/permanent damage done. BTW, we paid about $8 each for those 8" disks back then. Everything had to be sourced from Radio Shack.
 
I believe I made a couple of posts on adding a header to the controller board and using it to run a 3.5" drive and booting from said drive. I have a Model 16, but that's pretty much a Model II with 68K boards added. You do need the late-model controller to pull this trick off.
 
BOOT ERROR DC suggests that the drive controller timing(s) need adjustment... but it would be better to try a format of an empty disk first... one would need the manual (and an oscilloscope) to properly set the controller.

Looks like a GREAT find and I would be SO jelly if I had enough room for one myself! :D
 
Roland Huisman said:
Wow, this sounds like a serious design fault...
Were they magnetic destroyed and could they be reformatted?
Or were the disks mechanically damaged?

Regards, Roland
Click to expand...

No, actually it was a 'common design fault'. Users KNEW that the machines were 'pure evil' and would mess with you at every turn! :p
Seriously tho... it was EXPECTED of the user to follow the instructions, connection procedures, and 'rules'.... 'Idiot-proofing' came later, when we got too busy to 'think'. :D
 
Isn't the Model II the one with the strange loop-back drive termination? (The Model 16 doesn't use it). Might be your problem there. Seems as if we went through this with Lorne a few moons ago.
 
Hello guys, thanks for the replies!

I'd check the drive again, there was a part missing
to press the disk onto the head. I realy don't know how to call it.
I'd took it from one of the tree other drives which is missing the PCB.

CIMG3354.JPG

The error is now constantly "BOOT ERROR TK"
It seems to be a not usable boot disk according this website:
http://home.claranet.nl/users/pb0aia/cm/m2errors.html

Besides, the bootdisk was in the machine when I got it.
So maybe it got zapped the last time it was used?

The disk terminator is in the right place. (But if I remove
it the "BOOT ERROR TK" message still appears. No changes.)

If I place any other non-bootable disk into the machine the
message "BOOT ERROR RS" appears. Which means
"No radio shack operating system format"

So I really think the boot disk is erased...

Regards, Roland
 
Last edited:
It's more than likely the disk got hosed. Trying to use the drive with the missing felt pad wouldn't do it any miracles either.
 
Roland,

Download this PDF. http://electrickery.xs4all.nl/comp/trs80m2/doc/MODII_16_TRM_FDC_REV.pdf

Check PG 16. If this is the floppy controller you have, then you have the later revision and do not require a terminator loopback.

If you are using an original Radio Shack floppy diskette, I'm not surprised it's dead. I haven't found an original RS 8" disk that works. If you look at the disk you will see concentric circles on the disk surface where the oxide has been scraped off by the head like a scratch and win lottery card. :)

If you wind up needing a good boot disk, send me a private message via the forum with your snail mail address.

Cheers!

Kevin
 
It is not uncommon (and actually recommended practice) to transport a machine/drive with the cardboard insert OR a 'sacrificial' disk... to prevent 'head damage'.

It is (unfortunately) possible that the head is off by 'just enough' to keep it from reading properly... but it would be best to try a KNOWN GOOD disk first before going all hinky on the drive.

Were you referring to the arm with the head on it? OR the 'other side'??? (hopefully!!!)
IF it IS the head-side, you likely have MAJOR alignment issues... unless you got SUPER-LUCKY! :eek:

Will hope for better things! :D
 
If you have the new one, note that there is a 34-pin unpopulated connector area below the 50 pin one. Add a connector there, jumper a couple of pins and you can run 34-pin hgih-density floppies using that controller.
 
Hello,

Thanks for all the information. The controllerboard seems to be the old version.
I'd found a date inside the machine. Seems to be week 7 from 1980.
This date might be to early to have the new board also...

So no other drives seems to be supported than...?

Next weekend I'll make trip to Rotterdam to copy some disks from Fred Jan.
I'll keep you all informed about the progress...

And I think the next problem might be the keyboard. I've read some stories
about aged foam giving problems.

Regards, Roland
 
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