Leak Trough Line 3 Service Manual

Page 1

'TnousH LINE 3'
F.M. TUNER

mmm-mmmm-ummum INSTALLATION ' OPERATION ' MAINTENANCE

CONNECTING THE F.M. TUNER

1. This unit may be used free-standing on a table, or it may be mounted on a panel ofany thickness, through
a cut-out of 10% X 3% (27-5 x9-5 cms.). To mount on a panel: take on" the cover by removing the wing-
screw which passes through a hole in the cover fixing bracket and threads into a hank-bush in the centre
of the rear panel of the tuner, Pass the body of the tuner through the cut-out until the front plate butts
against the panel, replace the cover and wing-screw and tighten just enough to prevent the front plate on the
tuner from slipping on the panel.

2. The mains transformer primary is wound for voltages of 110, H7. 130, 210, 230. 250 (50 to 60 c/s). The
circular voltage selector (situated at the back of the tuner) should be withdrawn to its fullest extent, rotated
so that the arrow indicates the voltage nearest to your supply and then reinserted.

3. When used with a LEAK power amplifier the mains supply for the tuner can be obtained by inserting the
A.C. POWER plug into the A.C. OUTLET socket on the power amplifier. The tuner is switched on by
turning the volume control.

4. The 300 ohm aerial input is balanced to earth. When using 300 ohm twin feeder, the conductors should be

connected to the outer aerial terminals. When using an unbalanced 70-80 feeder, the inner central conductor
should be connected to either of the outside terminals and the outer screening connected to the centre chassis
terminal.
In many localities (covering perhaps 80% of the population) good reception of the B.B.C. transmissions
will be possible with an indoor aerial, but it should be remembered that the signallnoise ratio will always
be better with an elficient outdoor aerial. Even with a very sensitive receiver such as this it is desirable to use
an outdoor aerial correctly orientated, the optimum position being indicated by maximum closure of the
tuning indicator pattern.

5. The output voltage from this tuner is approximately l volt r.m.s. Due to the use of a cathode follower
output stage the output impedance does not exceed 12,000 ohms. This means that up to 20 ft. of low-loss
co-axial screened cable can be used to connect the tuner to its associated pre-amplifier without audible loss
of high frequencies.

6. This tuner unit is earthed to its associated pre-amplifier via the screening of the AUDIO OUTPUT lead,
and no additional earth connection should be made to any part of the tuner.

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OPERATING THE F.M. TUNER

7, The tuning indicator used on this FM. tuner is of the maximum closure type and only becomes operative
when the AFC is switched OFF. In order to tune in a station. it is» therefore necessary to switch off the
AFC and adjust the tuning control until a minimum gap exists between the two vertical light strips. Switch-
ing the AFC "ON" locks the station in tune and removes the HT (8-) supply from the tuning indicator.

8. In locations of very high signal strength. the sensitivity switch should be set to LOCAL: following this
procedure will suppress some of the unwanted inter-station noise.

Frequency Range:

Drift:

Sensitivity:

Aerial Impedance:

Audio Output:

Multiplex Output:

Power Supply:

Valves (Tubes):

Dimensions:

Mounting:

Weight:

SPECIFICATION

88-]08 Mc/s.

3 kc/s'maximum with AFC ON, l5 kcs maximum with AFC OFF'
l 5 micro-volts at the aerial terminals for full limiting.

The choice of 300 ohms balanced or 75 ohms unpalanced.

Cathode follower output delivers approximately volt r.m.s. and facilitates the use
of long output leads with negligible high freque cy attenuation.

For connection to a multiplex adaptor to obtaih stereophonic reproduction from
stereo F.M. transmissions. where available.

0, H7, I30. 2l0. 230, 250 volts. 50160 c s consiimption 45 watts.

2 x ECF80. ECC84. ECCSS. EF80. EM84. ElZ80. 2 x OA79. l festoon lamp
6V 2 watt. .

Hal" x4i' X 8i" deep.
(Z9-2x10'8xllcms.).

Free-standing on non-scratch felt feet or panel mounted through a cut-out of
I0§'x3i'(27.5x9-5cms.).

|2 lbs. 8 025. (5'65 kgs.).