TRS-80 Model II

From: Lawrence Walker <lwalker_at_mail.interlog.com>
Date: Tue Feb 17 16:29:00 1998

On 18 Feb 98 at 19:43, Fritz Chwolka wrote:

> Great... that you got such a fine part.
>
> I've a TRS80 MII too but without a harddiskdrive.
> For other use I add an extern DSDD 8" diskdrive.
> The internal diskdrive is singlesided I believe it's a shugart 801.
>
>
> I got several errormessages during bootup every time I tried to do
> so which was every 2-4 months.
>
> My problem was the dispositioned head of the diskdrive.
>
>
> (1) --------------------\
> ---------------+ !
> !----!
> (2) +-----+__ 1_2_3_____...77+----------
> !_____+------------------+__________
> (3) -------------- /====\
>
>
> There I trie to show the disk with head and the part against the head
> for the singlesided drive.
>
> If you put in the disk between part (1) and (3) must be place enough to
> insert
> the fleydisk into the drive. If there isn't enough place the disk will
> become
> contact with part (1) or (2) and you throw the head backwards. If you
> don't recocnise it and after some triese are able to get the fleyxdisk
> into
> the drive you change the correct position of the head against track
> zero.
>
> Normaly the head must find track oneduring bootup. If the system boots
> the diskdrive will reset the position of the head(s) and a indicator
> says
> now the head is in Track 0 position. The the stepper stepps backwards
> from track
> to track.
>
> Dispositioned head:
>
> (1) --------------------\
> ---------------+ !
> !----!
> (2) +-----+__ 1_2_3_____...77+----------
> !_____+------------------+__________
> (3) -------------- /====\
>
>
> Here you see that the head can't stepp backwards during the poweron /
> reset time
> because during inserting the flexydisk I dispositioned the head.
> The distance between (1) and (3) was to small because part (1) fall down
> from
> the metallplate which make the headload.
> Now during boot I got a DC error.
>
> It's a nice mechanical problem in my case and maybe you have the same.
> Even the indicator for Track 0 maybee dusty or inoperable.
>
>
> Greetings
>
> Fritz Chwolka / collecting old computers just for fun.
> +-----------------------------------------------------+
>
Thanks. It seems to insert easily. I also have an external
FDD. Will your external boot up if you don't have the gate closed on
the internal ? I'll have to open them up and see what I can see.

ciao larry
                       
lwalkerN0spaM_at_interlog.com
Received on Tue Feb 17 1998 - 16:29:00 GMT