Eico ST 70 Schematic

Page 1

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£9"

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' H ' 680K m
330mmf 100 PRE-AMP W
@ [CBfl/HAX? 3 3ja 7 1/2

TAPE EQUALIZAIION .__

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_ FM
21 2 1 o
o o SECTZREAR l
-, o 30 r) 10 n
o z o 9 90
O
1- . o O 8 2
"7 SIRI-
SECTI REAR SECTl FRONT up: Aux - F .
MXAUX c --
n-uw '- I . I u _ _ 1-. In- I -
® 200K dmeg @
ANT
400mm 101» 0012 10-1. 7
@ 10011
SELECTOR szTcN
SIIOINN IN POSITToN 1. ® @ @
SWITCH S£OUENCEz N'- ' " "' " "
T. TAPE-Aux 130mm 100 PRE-AIIIP Lm 00011 150K
2. NIX-AUX
3_ mm ® [CCWHAXI 7 1/2 3 3/4
4. AM-AM @ . 05v 1 new @ __F @
3- figfigg ov -... 1m EQUALIzATI
lNPUTS T. TAPE HEAD 22K l 1,25 AM 2 1 1
2- 5 g g]
"5 0 SECHFRONT 912 7 0° 0 ® 1' 3
0'"
.911 L. n
@ lmeg OV 200K 00 o
D O O
6
T v ? SECTB FRDNI
30 3E0T3ITEAR
MX Aux
' i "
PHONOB _ _ _ J
@ @ 240 lTAPEII x J _
" 400mm! 101. ? .0012 101. if
PNONOA I «M, 1 _I-w:-- L - --- - 1 -- - -
NM 40109
RESISTANCE READINGS
ITEM TUBE Pin_l I Pin2 .. Pins ' Firm-I Pin; Pino rPinIfi Pin_8 L Pin9
E0033 22K 2400::
.VI 12? 160K L1.smeg 1i12000 FIL FIL 134DK mm JD rTIL
1031: on 15000 FIL Fll. t63K 2:33 10000 TIL
1345K 20" £11000 LFIL FIL 1345K 120011 1P111100 Fll
. .I470K __ T 1.470K _' 1.
V4 1345K 133K 18K 11.3w; t37K 10x FIL HL
1 III t r 4r i:
lvs TP EIL 11200 113000 100 200K FIL 110000
T Ii -+ ll - Il I-
vo 7591 T? FIL 11300 113000 100 200K FIL 110000
I l_ _, _ a -J
Eccss 22K 24000
W $12? 100K 1.5meq 12000 Fll. rFiL T1340K almeg H.011 LEIL
v3 7247 t63K on 15000 EIL TIL t63K 220K 10000 EIL
_1 r 1 .07011 i
w LSNTGT t345K 133x 101: H.3meq 132K 18K FIL E11 1
i I r 1- J
1/10 2591 IR FIL 11200 110000 100 200K FIL 110000
V11 2591 TP FIL 11300 110000 Loo 200K FIL 118000 J
NUMBERS ASSIGNED To cons. SWITCHES, PLUGS. SOCKETS. AND 5234
LRANSFORMERS ARE To EAcILITATE CIRCUIT TRACINo OR 0011- V12 my "C 3 24° C 33 C
Tflfiflffl'mmm "ND M 01 "SSARM 35 um 0 1 THIS READING MLLVARY DEPENDING UPON THE CONDITION OF THE ELECTROLYTIC IN THE CIRCUIT.
ALL MEASUREMENTS MADE IN CHANNEL 01 "TAPE-Aux" POSITION wmI ALL FILTERS OFF UNLESS OIHERWISE
- MEASURED IN "Nix-AUX" POSITION. DESIGNATED.
- MEASURED wITH "LO FILTER" ON.
9 SE! was LIST Eon ALTERNATE 1 MEASURED FROM PINS DFV12. Nc No CONNECTION TP TIE POINT

VALUE 0R APPLICATION

1. DC voltage measurements taken with vacuum tube voltmeter;
AC voltages measured with 1000 0th per volt voltmeter.
Socket connections are shown as bottom views.

Measured values are irom socket pin to common ground.
Line voltage maintained at 117 volts for voltage readings
Nominal tolerance of component values makes possible a
variation 01 : lfiin voltage and resistance readings.

All controls at minimum, proper output load connected.

\JPWN

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A PHOTOFACT STANDARD NOTATION SCHEMATIC
cHemu'arizl W. Sam: & Co., Inc. 1962