Table of Contents
Advertisement
7. Replace· Transport Electronics PC board.
Don't
forget to reconnect molex receptacle attached to
the new Portescap motor assembly.
8. Check tape speed and ramp time as follows
(readjust if required):
TAPE SPEED ADJUSTM ENT
Procedure No.1
(Use with machines containing read after write
heads.)
1. Connect
channel
1
probe
of a
dual
trace
oscilloscope to the input write data. A convenient
location would be P9-1 of the Write Head Driver
board.
Trigger scope on channell and-select 2
ms/cm time constant.
.
2. Connect channel 2 probe to test point
B
and write
on channel 1.
3: Write short blocks, one to ten characters long.
4.
Adjust
potentiometer
R66
on
the Transport
Electronics board so that the delay between the
first write strobe and the leading edge of the read
data block is 12 ms at 25 ips.
For machines
operating at other tape speeds the formula for'
deriving the proper delay time is
0.3
d I
.
S
= e
ay
In
ms
where s
=
tape speed in inches per second.
Procedure No.2
,
(Use
with
machines
containing
combination.
read/write heads.)
. Special equipment re<:)uired:
Speed Tape Gartridge,
Kennedy Part Number 198-0045-001.
1. Connect oscilloscope probe to test point B. Select
read operation.
'.
193-0119-200A
2. Select
8
2
ms/cm
time
constant
on
the
oscilloscope.
3. Adjust R66 on the Transport Electronics board for
8
10 ms read pattern length which is 44 ANSI
compatible characters long.
RAMP TIME CHECK
Tape is brought up to speed at constant acceleration.
To control tape velocity, a linear positive or nega tive
ramp voltage is generated. Ramp time is 30 ms (+0 -
5 ms) at 25 ips and varies inversely with speed. Ramp
voltage is positive going in reverse; negative going in
forward mode.
Oy
110-0103
where
I
I
I
I
I
,
I
_ _ _ START-:
•
lAM'
T-151.!-MSEC
S
T
=
ramp time in milliseconds
: _ _ STOP
RAMP
S
=
tope
~pccd
in inches per second
To Check Ramp Time
1. Establish rapid start/stop motion.
2. Observe waveforms at
test point
A on the
Transport Electronics board. Synchronize on RUN
command. Be sure time is long enough to produce
a flat area between ramps .
3. If
ramp
times
vary
significantly
from
specifications, the ramps should be adjusted by
changing the value or R63. A higher value of R63
results in a faster ramp time.
Advertisement
Table of Contents
