Input-Output Conditions And Terminals - Teac C-1 Service Manual

TAPE TRANSPORT SECTION
1-2 INPUT-OUTPUT CONDITIONS AND TERMINALS
Refer to Fig. 2.
POWER SUPPLY
| SUPPLY Vss & CLOCK INPUT
POWER SUPPLY meee
RESET INPUT RES Voo ER SUPPLY J
STOP INPUT STI WT WAIT OUTPUT J output
RECORD INPUT RCI
ECORD RWO REWIND OUTPUT ) INPUT?
RECORD SAFETY INPUT RSI FFO FAST FORWARD OUTPUT | QUTENE
RECORD MUTE INPUT — RMI R/BO REVERSE/BRAKE OUTPUT ]
INPUT YM-276
( TOP VIEW
STAND-BY INPUT sel ) SBO STAND-BY OUTPUT
PLAY INPUT PYI PYO PLAY OUTPUT OUTPUT
FAST FORWARD INPUT FFL RCO RECORD OUTPUT
REWIND INPUT RWI RMO RECORD MUTE OUTPUT
a
MOD MODE INPUT
INPUT
REVIEW INPUT RVW
MN1I Me REVERSE/ MOTION 2
fu Me INPUT
MOTIONT INPUT MNi
T~\290
Fig. 2 LSI Input/Output Terminals
Pin 1: Power supply terminal
When Vo is zero volt, the recommendable operating
condition of Vss is such that Vss = +10V ~ +16V.
Vss is 12V in the C-1. Vss ripple must be under
100mVp-p.
Pin 2 ~ 14, 24: Input terminals
Input high and low levels are given in Fig. 4.
As can be seen from Fig. 4, the high level range is ex-
tremely narrow. Thus, when a diode logic circuit is
used in conjunction with the input circuit, the voltage
Fig. 3 LSIt Outside View
drop in the doide must be taken into consideration. Higa eeveL SSS a ee
D504 is used to conpensate for the voltage drop due to eee OS Poe
D501 to D503, D505, D505, etc. The input circuit ea
from the operation switch to the LSI is as shown in —_———————_—_———_ 5V_tvss~7v)
Fig. 5. LOW LEVEL
The integrating circuit comprising R1 and C1 eliminates iv sv)
high frequency noise. When the input to the LSI is at T1291
the high level, the current flowing into the LS] is as low
as about 10 uA. If the insulation resistance between the Fig. 4 Input Signal Logic Level
high level terminal and adjacent terminals falls due to
dust or moisture, current may leak into the LSI and +13V
actuate it accidentally. To prevent this, R2 (10K) ie
is provided in the LSI to ground leakage current if it is OPERATION cy, Est
present SWITCH 0.01 T
T-1292
Fig. 5 Switch Input Circuit