Power Supply - Kennedy 331 Operation And Maintenance Manual

For example, when the cartridge is ini-
tially inserted a rewind operation should
be performed. A fast reverse command
is issued until both the A and B holes
are detected simultaneously in reverse.
When they are, beginning of tape has been
reached and fast reverse should be
dropped. If it is desired to advance to
load point, run forward should be issued
until the A hole is detected in the for-
ward direction. This position on tape ts
LOAD POINT. The next time the A out-
put is detected in the forward direction,
the end of tape warning position has been
reached. Continued forward tape mo-
tion should only be allowed until both the
A and B outputs are simultaneously
detected signifying end of tape.
1.8 READ/WRITE SECTION
Pin V - READ DATA (RD). Data is presented in serial
format, TTL compatible, and consists of coded flux
transitions. A 0 transition is defined as a voltage
transition from low to high at the interface. A 1
transition is defined as a voltage transition from
high to low at the interface. READ DATA OUTPUT
is forced high (false) during the read gap. The par-
ticular track to be read is selected by means of a low
true SD1, 2, 3, or 4 input, which is determined by the
states of SELECT A and SELECT B interface Sig-
nals. Read Data output is forced high (false) during
the Read Gap.
Pin M - WRITE DATA (WD). Serial input data in the
proper phase encoded format, including preamble,
CRC, and postamble, are presented on this line.
Write data consists of encoded flux transitions. The
polarity of this signal is such that a high (false) input
state generates the ANSI standard erase polarity for
gap generation.
Transport electronics consist only of write head
drivers on the Write Head Driver board. WRITE
ENABLE must be true (high) before write data can be
applied to the selected write head. Write head selec-
tion is accomplished by means of SELECT A and
SELECT B interface signals.
1-7
106-0331-700A
Pin K - SELECT A. When combined with SELECT
B, this level selects one of four tracks for read/write
operation. A table of the logic states required to
select each track is furnished on the Transport Elec-
tronics schematic.
Pin L - SELECT B. When combined with SELECT
A, this level selects one of four tracks for .read/write
operation. A table of the logic states required to se-
lect each track is furnished on the Transport Elec-
tronics schematic.
Pin N - WRITE ENABLE. When true (low) this level
enables the write head selected by SELECT A and
SELECT B signal states. When false (high) this level
disables the write heads.
1.9 POWER SUPPLY
The Model 331 requires ±24 vdc unregulated and +5
vdc regulated supply voltage for operation. The
30 ips version of the Model 331 requires ±27 vdc
nominal +20%-10% , in place of the +24 vdc.
The +24 vdc unregulated is reduced to ±15 vdc regu-
lated by a regulator circuit on the Transport Elec-
tronics board. Table 1-2 lists the current and voltage
requirements of the Model 331.
Voltage
+5v ±3%
+24v +20% -10%
-24v +20% -10%
Current
Maximum O. 95A
Maximum 3. OA
(100 msec surge whe n
ramping - average 1. OA)
Maximum 3.0A
(60 msec surge when
ramping - average 1.0A)
Table 1-2. Power Supply Requirements