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(a)interlog.com