#004 07 января 1987

Drivechat

 First a hint for adventurous
Microdrivers.

 If you find your drive rather
noisy , prone to chew carts or
erratic on loading ,you may like
to try this. First take off the
metal cover plate (the bit with
the coloured stripes on) ,its
only glued down with sticky
tape. You should see 2 screws,
remove them & GENTLY open the 2
halves , starting at the front. 
Be careful as the little red LED
can come loose! There will be
enough lead though to allow easy
access.

 The first thing to look at is
the rubber roller , as it can
become either deformed (BAD!) or
just plain dirty! To clean it &
the head for that matter , use a
tape head fluid on some lint
free material (soft chamois
leather?). Also reset the motor
position , as this often moves
for some reason.

 To do this SLIGHTLY loosen the
2 small screws that hold the
motor in , Now GENTLY push the
motor backwards & to the right.
This can be done by using your 
little finger , inserted just
below the plate the motor
attaches to. (If your finger is
too big use a pen top!)

 While holding it there re-
tighten the 2 screws , be gentle
though as the chassis is only
plastic! At this point the extra
brave may like to try it out!
This is OK but you must gently
hold the cart down as you insert
& run it or the cart may do an
impression of a Harrier Jump
Jet!

 Assuming all is well you can
re- assemble the drive. Make
sure the rear 'tongue' is
located correctly & the LED is
still in its hole before  
lowering the front of the top
cover. Now just replace the
screws & the plate! While you
are about it its a good idea to
clean the edge connectors on
both IF1 & the drive as well to
prevent file not found errors.

 On the same sort of subject
.... Beware the slow drives! Yes
some drives do go slow ,either
they were made that way or they
have been tweaked! They usually
FORMAT a cart to quite high no's
of K but if you try to use a
cart FORMATted on another normal
drive the gaps you were
describing tend to get over-
written & any data that is on
the cart can be unretrievable! 
 If you get a looped cart then I
 find the best way of winding the
 tape back is to use the stick
part of a cotton bud held
against the white roller pretty
good! 

It goes without saying , I hope
that ANY tampering with the
inards of hardware MUST be done
with it switched off!

 128K hint -Does your 128 have a
 disturbed picture whilst running
 drives? Yes?

 This is usually due to the
regulator having a poor
connection. If you remove the
top of the computer you will see
the regulator screwed on the  
the heatsink at the right hand
side. It has a connector holding
the wires on , check which
colour goes to which pin (some
are different!) Cut the silly
plug off & re solder the wires ,
cut just long enough to reach ,
to the Regulators pins. Instant
steady pictures. Of course the
mod means you have to unsolder
the wires to remove the PCB....

             - Brian Gaff 
Thanks Brian, for those hints.

I'd just like to add to what
Brian was saying about cleaning
the edge connectors.

This is an old, old tip which
many of us have heard again and
again but it's so important that
we might as well state it here
in DRIVECHAT just for the
record...

It is strongly recommended that
you regularly clean the edge
connector at the back of the
Spectrum and the Interface 1
connector as well as the side
connectors to the microdrive(s).
The oxide which otherwise builds
up is a common cause of the  
system refusing to accept
Interface 1 commands or failing
to recognize the presence of the
microdrive. It's best to use a
soft, clean, rubber eraser to dot
he job as it has been said that
spirit may degrade the
connectors.

The clips in the Interface 1
connector are tricky - I use an
elastic band! What do others
use?

How often should you clean the
connectors? I reckon about every
six months to a year. Mind you,
I use my Spectrum about 35 hours
a day so I suppose I ought to do
it more often. Still, I
generally find that after 6 to  
12 months I get the tell-tale
signs - I enter CAT 1 or
something and my Spectrum goes
"Huh? CAT 1? What's a CAT 1?".

Perhaps I shouldn't say this but
if you only use your Spectrum
for a few hours a week and have
never had any problem signs then
I'd be tempted to leave well
alone...

Now a quick tip for those people
who have the Sinclair Copier
that came with the expansion
pack. If you want a fast way of
verifying the copy made just try
to copy it back. The copier will
re-load it and attempt to
re-save it back where it came
from. If all is well it will 
display the "
file exists "
message which means it success-
fully loaded it back into
memory. The system does not
crash so you can do this with
multiple copies.

A final tip - again with the
Sinclair Copier.

You know how the BASIC is
automatically erased after
loading leaving just the info
message? Well that means, of
course, that you must then type
in the commands direct, type in
your own BASIC or LOAD some
further BASIC you've prepared.
I'd been meaning for ages to
hack into the code to remove the
instruction that wipes out the  
BASIC so I could write my own
BASIC routines and load the code
into MY BASIC. It would save
keep typing in all that "*MOVE
"M";1;"BORING" TO "M";2 stuff
repeatedly.

Of course, you can't normally doth
at because the code just
erases your BASIC when you make
the RANDOMISE USER call! Just a
few days ago I realized the
answer! I didn't need to hack
the code at all! All you do is
point the Interface 1 system
variable VECTOR at the right
address and Bob's your uncle!

To do this, write your BASIC
program (You can have mine if
you want but I don't know how 
many OUTLET readers have the
Sinclair Copier and my BASIC
wouldn't be any use to those who
don't!).

At the START LINE in your
program you need: CLEAR 25999:
LOAD *"M";1;"ORIGINAL NAME OF
THE SINCLAIR CODE WHICH ESCAPES
ME FOR THE MOMENT - SORRY!":
POKE 23735,173: POKE 23736,101.

THAT'S IT! - NO RANDOMISE USER
CALL NEEDED! You just load the
code and point VECTOR at the
right address within it and
Interface 1 then recognizes the
special MOVE commands! Great!
Wish I'd thought of it two years
ago! Since that time I've typed
in *MOVE...etc., 398,202 times! 
Anybody know who now has the
copyright to the code? I know
Andy Pennell wrote it for
Sinclair. Since it was given
away free with the expansion
pack it ought to be made public
domain software. As it is it
seems nobody can get it now -
Shame!

              - Brian Cavers.