Acoustical Manufacturing Co. QUAD MULTIPLEX DECODER Instruction Book - Page 4

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lNSTALLATION

Preparing the FM Tuner

If the Serial No. of the Quad FM tuner is

above 19062 a switch is fitted near V6 (see fig.

1). When used with the Multiplex Decoder the

switch should be moved to the stereo position,

marked RED.

If the Serial No. of the Quad FM tuner is

less than 19062 the tuner should be modified as

follows:-

(1)

Disconnect capacitor C33 (.040) from

pin 5 of valve V6 (6AL5). If this com

ponent is left in position the lead wire

should be placed so that accidental

contact cannot be made with any other

part of the circuit. Replace C32 (47p)

by a capacitor of 15p.

(2)

Remove the Brown audio lead from the

pillar tag at the junction of resistors

R20 (220K), R21 (100K) and capacitor

C34 (lOOOp).

(3)

Connect the Brown audio lead via a

2.,2K resistor (Dubilier BTT or equiva

lent) to pin 5 of valve V6 (6AL5). Keep

the resistor close to pin 5 (see fig 2).

Connections between units

The FM tuner - Multiplex Decoder - Quad

22 control unit connections are shown in fig. 3.

The Multiplex Decoder may be fitted on the

rear of the Quad FM tuner cover by removing

the tuner cover fixing screws and replacing them

through the holes in the sliding bracket under

the decoder cover (see fig. 4).

The optimum performance for the decoder

will be obtained in moderate temperature. If

the cabinet ventilation is such that the air in the

FM tuner compartment exceeds 40°C (104°F)

the decoder should be moved from the tuner

cover and placed in a cooler part of the cabinet,

e.g. near an air intake on the cabinet floor.

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