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New patient in the hospital - TRS-80 Model II

N

nblsavage

Experienced Member
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Aug 8, 2008
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101
Location
Beaverton, Oregon
Just came back from Goodwill Outlet with a TRS-80 Model II. She's in pretty banged-up shape but does power on. I get the following message when she boots - "OT ERROR DC".

I did open her up and reseated all the cards, beyond that I'm not sure how to proceed. My TRS-80 experience is limited to a BASIC programming class in HS.

Well, after looking online I'm supposing it's a lack of a bootable disc that's the problem.
 
Ok, got a bit further after reseating the cards again and reseating some of the chips.
I get all the way to "64 K" - "INITIALIZING" and then....
**ERROR 40**
Critical Read Error - Abort

The disk that was in the drive when I got it doesn't appear to be anything other than someone's old database. So am I correct in assuming it I managed to get a TRSDOS boot floppy, I'd be heading in the right direction?
 
I have looked through the operation and the Technical manual and I can't find any error 40 listed. The DC error you previously got was a floppy error indicating either a bad diskette, controller or drive.
The startup diagnostic routine first writes to the video memory to produce an all white screen, checks ROM, then the CPU registers, followed by a testing of RAM. If there are any problems with RAM it should give an "MF ERROR". The only things left are flushing the keyboard buffer and displaying "Insert Diskette". There are several error codes after this , but they all involve floppy errors. Make sure you leave the floppy door open when you boot and see if you get the "Insert Diskette" message. If you do, then your problem should be either the diskette, controller or disk drive.
 
Last edited:
Chuckster_in_Jax said:
I have looked through the operation and the Technical manual and I can't find any error 40 listed. The DC error you previously got was a floppy error indicating either a bad diskette, controller or drive.
The startup diagnostic routine first writes to the video memory to produce an all white screen, checks ROM, then the CPU registers, followed by a testing of RAM. If there are any problems with RAM it should give an "MF ERROR". The only things left are flushing the keyboard buffer and displaying "Insert Diskette". There are several error codes after this , but they all involve floppy errors. Make sure you leave the floppy door open when you boot and see if you get the "Insert Diskette" message. If you do, then your problem should be either the diskette, controller or disk drive.
Click to expand...

I do indeed get the "Insert Diskette" message. After putting the floppy in it gives me the "64K","INITIALIZING" messages and after attempting to read the disk, throws the read error.
 
Yea, could be disk, drive, or controller. The trick is to try to islolate one of these, so you can undertake further work.

I know little about the Model II. First thing I would try to do is get a known, good boot disk (in fact, get several copies in case a damaged disk drive zaps one). It does need to load an operating system off a floppy. Is there somewhere you could get hold of one, or do you know anyone with a working Model II who could check the disk (and if ok, make copies).

If the disk turns out ok, and it still won't boot, try re-lubing the drive rails, cleaning the head etc. as has been described in a number of posts in here.

If that doesn't work, try swapping the drives around (some settings on the drives may need to be changed). If this works, then it probably is a problem on just one of the drives. If it doesn't work, it could be the controller is damaged (or both drives might be faulty..this is not so common though.).

Good luck!

Tez
 
tezza said:
I know little about the Model II. First thing I would try to do is get a known, good boot disk (in fact, get several copies in case a damaged disk drive zaps one). It does need to load an operating system off a floppy.
Click to expand...

Yeah, therein lies the problem. The drive is an old 8" :) I did come across a hack online to use 5 1/4 drives, so I might try to attempt that assuming I can find a 5 1/4 drive to use.
 
Chuckster_in_Jax said:
There was a recent discussion on this forum regarding the Model II boot problem. Here is the link:

http://www.vintage-computer.com/vcforum/showthread.php?t=11858&highlight=terminator

The terminator looks like this and is very rare and hard to find. It fits in the connector labeled "disk expansion" on the rear of the unit. It looks like this:

http://www.nekochan.net/~neko/images/PICT1616.jpg
Click to expand...

Ouch - I also saw that you linked to the manual for the 801 in that thread. I might try experimenting with the termination jumpers on the drive and see what happens.
 
With the system turned off, manually move the head carriage all the way forward and see if it returns to track 0 smoothly. If not clean the rails (and the head, while you're at it).

There is an arm that hold the diskette against the R/W head and, on it, in the circular part (if it's a Shugart) there should be a plastic "button" with a felt pad in the center which presses against the non-R/W side of the diskette. Check to make sure it's there.

Even if it is, get a small slot screwdriver and turn the Head Load Pad holder (the plastic part that the felt is attached to) 180 degrees in the arm (they wear unevenly) by reaching around to the back of the arm holding the HLP putting the blade of the screwdriver in between the two little plastic tabs you'll see there and slowing turning the whole HLP.
 
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