TECHNICAL INFORMATION AND SERVICE DATA
RADIOLA
Models 776-GA and 778-GA
SEVEN VALVE. TWO BAND, A.C. OPERATED SUPERHETERODYNES
ISSUED BY AMALGAMATED WIRELESS (AUSTRALASIA) LTD.
ELECTRICAL SPECIFICATIONS
Frequency Ranges
| Medium Wave |
540 — 1600 Kc/s.
(555 — 187.5 Metres) |
|---|---|
| Short Wave |
6 — 18 Mc/s.
(50 — 16 Metres) |
| Intermediate Frequency | 455 Kc/s. |
| Power Supply Rating |
200 - 260 volts
50 - 60 c/s. |
| Power Consumption Reco |
Receiver — 75 watts
d Player — 16 watts. |
| Dial Lamps 6.3 | volts, 0.25 amp. M.E.S. |
Valve Complement
(1) 6BE6 Converter (2) 6BA6 I.F. Amplifier (3) 6AV6 Derector. Tone Control Amplifier, A.V.C. (4) 12AX7 A.F. Amplifier. Phase Splitter (5) 6V6GT / Push-pull Cutput (6) 6V6GT / (7) 5Y3GT Rectifier
Loudspeakers
1 — 6 inch bermanent magnet No. 20766 1 — 7 x 5 inch bermanent magnet No. 20922 1 — 12 inch permanent magnet No. 20933 Transformer No. 25861 V.C. Impedance of Combination 15 ohms. at 400 c/s. Undistorted Power Output ..................................
Chassis Removal:
Remove the cabinet back. The complete receiver comprises two units — Tuner and Power Amplifier.
Remove the Broadcast aerial lead from the Ferrite Rod and the S.W. aerial lead from the spring terminal at the rear of the chassis.
Disconnect the Power Supply, Pick-up, Loudspeaker and Cabinet Indicating Lamp cables.
Each unit is reld in the cabinet by two screws through the mounting boards. Removal of these screws enable the chassis to be withdrawn.
Drive Cord Replacement:
The accompanying diagram shows the route of the cord and the method of attachment.
Connection to Power Supply:
The receiver should not be connected to any circuit succiving other than alternating current from 200-260 volts and at the frequency stated on the label within the cabinet.
The power supply connections are shown in the accompanying diagram.
Alignment Procedure
Manufacturer's Setting of Adjustments.
The receiver 's tested by the manufacturer with precision instruments and all adjusting screws are sealed. Re-alignment should be necessary only when components in tuned circuits are repaired or replaced, or when it is found that the seals over the adjusting screws have been broken.
It is especially important that the adjustments should not be altered unless in association with the correct testing instruments. listed pelow.
Under no circumstances should the plates of ganged tuning capacitor be bent, as the unit is accurately aligned during manufacture and cannot be re-adjusted unless by skilled operators using special equipment
For all alignment operations, connect the "low" side of the signal generator to the receiver chassis and keep the generator output as low as possible to avoid A.V.C.
action. Also, keep the volume control in the maximum clockwise position.
Testing Instruments:
- (1) A.W.A. Junior Signal Generator type 287003, or
- (2) A.W.A. Modulated Oscillator, series J6726. If the modulated oscillator is used, connect a 0.25 megorim non-inductive resistor across the output terminals, and for short wave alignment, an additional 400 ohm non-inductive resistor in series with the "high" output lead of the instrument.
- (3) A.W.A. Output Meter, type 2M8832
NOTE: On the short wave band the oscillator is working on the low side of the signal frequency; therefore, the image will now be heard if the receiver is tuned to a nigher frequency than the signal. For example, if the receiver is tuned to receive a 16 Mc/s. signal, the image will be heard at 16.91 Mc/s. instead of the usual 15.09 Mc/s.
| Order |
Connect "High" side
if Generator to: |
Tune Generator
to: |
ne Receiver
to: |
Adjust for Maximum
Peak Output: |
|---|---|---|---|---|
| ו |
Aerial Section of Gang
(Drive End) |
455 Kc/s. | 540 Kc s. | Core L13 |
| 2 |
Aerial Section of Gang
(Drive End) |
455 Kc/s. | 540 Kc s. | Core L12 |
| 3 |
Aerial Section of Gang
(Drive End) |
455 Kc/s. | 540 Kc s. | Core L11 |
| 4 |
Aerial Section of Gang
(Drive End) |
455 Kc/s. | 540 Kc s. | Core L10* |
| 5 |
Aerial Section of Gang
(Drive End) |
455 Kc/s. | 540 Kc s. | Core L9* |
| 6 |
Aerial Section of Gang
(Drive End) |
455 Kc/s. | 540 Kc s. | Core L8 |
|
*If the 1st and 2nd I.F.
then repeat the above |
are completely out of aligni
adjustments, peaking all co |
ment, "Une core 19 and L
bils. |
10 for a sharp dip and | |
| 7 |
Inductively coupled to
Rod Aerial† |
600 Kc/s. | 600 Kc s. | L.F. Osc. Core Adj. (L7)§ |
| 8 |
Inductively coupled to
Rod Aerial† |
1500 Kc/s. | *500 Kc s. | H.F. Osc. Adj. (C11) |
| 9 |
Inductively coupled to
Rod Aerial† |
1500 Kc/s. | `500 Kc s. | H.F. Aer. Adj. (C1) |
| Repeat the above adju | stments until the maximum | output is obtained. | ||
|
10
11 |
S.W. Aerial Terminal
S.W. Aerial Terminal |
16 Mc/s.
16 Mc/s. |
16 Mc s.
16 Mc s. |
H.F. Osc. Adi. (C8)‡
H.F. Aer. Adi. (C3) |
ALIGNMENT TABLE
+ A coil comprising 3 turns of 16 gauge D.C.C. wire and about 12 inches in diameter should be connected between the output terminals of the test instrument placed concentric with the rod aerial and distant not less than 1 foot from it.
§ Rock the runing control back and forth through the signal.
‡ Use maximum capacity peak if two can be obtained. Check to determine that the trimmer has been adjusted to correct peak by tuning the receiver to approximately 16.91 Mc/s., where a weaker signal should be obtained.
∢ Ω C Δ Ш Ⴊ L
CIRCUIT CODE --- MODELS 776-GA and 778-GA
| Vo. Description | Part No. I | Fig. No. L | ocation | Code No. | Description | Part No. F | Ŋ | location |
|---|---|---|---|---|---|---|---|---|
| INDUCTORS | č | 'n | ||||||
| Ferrite Aerial Assembly 540-1600 Kc/ | 34327 | - | B5 | 90 |
o.ι μι paper zuuv working
0.0022 μF paper 600V working |
5
5 |
||
| Aerial Coil 6-18 Mc/s | 28228 | F6 | C8 | 2-20 μμF Trimmer | 19659 | 3 8 | ||
| Oscillator Coil 6-18 Mc/s | 28229 | _ | F3 | C9 | 12 445 μμF tuning | 18674 | 10 | |
| Oscillator Coil 540-1600 Kc/s | 32406 | +2 | C10 | 470 µµF padder ± 21% | _ | F2 | ||
| ist I.F. Iranstormer | 34384 | C7 | CII | 4-27 μμF trimmer | 33304 | - | F2 | |
| 2nd It. Lensformer | 34384 | - | C10 | C12 | 47 µµF mica | - | D5 | |
| 3rd I.F. Iranstormer | 33596 | C12 | C13 | 100 µµF silvered mica (in Est L.F.) | - | 10 | ||
| Hiter Choke | TU24 | e | D9 | C14 | 100 µµF silvered mica (in 1st 1.F.) | - | D7 | |
| RESISTORS | CI5 | 0.01 μF mica | - | E7 | ||||
| 21 | 100 µµF silvered mica (in 2nd I.F.) | - | D10 | |||||
| 11000 ahms 3 wall | ES | 100 µµF silvered mica (m 2nd 1.F.) | - | 010 | ||||
| 100 ohms 2 , | 2 : | 210 | U.I #F paper 400V working | ~ | E8 | |||
| 22 000 obme 1 | 220 April Silvered Intea (in 3rd F.F.) | - | D12 | |||||
| D5 | 220 μμF silvered mica (in 3rd 1.F.) | - | D12 | |||||
| EI3 | 1 | - | EII | |||||
| 47 000 ohme | 227 | |||||||
| E12 | 0.00 µr paper 200V working | - | G10 | |||||
| 470 | 0.00 µr paper 200V working | - | F12 | |||||
| 20442/3 | G9 |
(7)
20 |
Z5 μF 40 P.V. Electrolytic | - | F10 | |||
| G8 | 07.7 | 100 μμr silvered mica | ~ | E13 | ||||
| no megonm 2 | F12 | 727 | 4/ μμF ceramic | - | E12 | |||
| F14 | 220 | U.UI μF paper 600V working | - | F14 | ||||
| - , | E13 | C20 | 4/U μμΓ mica | ~ | G13 | |||
| negonn 2 | 613 | 0.0025 µr paper 600V working | - | HI5 | ||||
| to megonin tone Control (Bass) | 0.0000 | 0.005 µF paper 600V working | - | H14 | ||||
| 32852/1 | - | G14 | C32 | 0.001 μF mica | - | H13 | ||
|
1.0 megonin Tone Control (Treble)
12.000 -E |
32852/1 | _ | G14 | [33 | 0.025 µF paper 400V working | 2 | E6 | |
| _ | GI5 |
101
101 |
8 µr 525 P.V. Electrolytic | e | C14 | |||
| м писерении 3 | с. | ਿ | (F) | 0.01 µF paper 600V working | 2 | E3 | ||
| 2 | C2 | 1.36 | 0.025 paper 400V working | 2 | C4 | |||
| .72 megohin 1 " | 2 | 12 | C37 | 0.025 paper 400V working | 2 | B.4 | ||
| .700 ohnis 1 | c1 | 810 | C38A | 16 µF 525 P.V. Electrolytic | · ~ | ŝ | ||
| .1 megohm 1 " | 2 | B3 | C38B | 8 μF 525 P.V. Electrolvtic | , r | 30 | ||
| 1.0 megohm 1 " | 2 | 10 | C39 | 0.5 µF paper 200V working | 2 | 9 | ||
| .200 ohms 3 | 2 | D4 | - | denartari | ||||
| .l megohn l " | 2 | 83 | C-10 | 0.025 µF paper 400V working | - | ( Laver den | ||
| ).47 megohin 🚦 " | . 2 | C I | C41 | 0.1 µF paper 400V working | ||||
| 0.000 ohms } , | 2 | 2.7 | C42 | 10 μμF mica | - ~ | |||
| 13,000 ohms } " | 2 | Dé | - | L Z | ||||
| 1.47 megahm 1, 1, | 7 | 3 0 | IRANSFORMERS | |||||
| 0,000 ohms 1, " | 2 | DB | 11 | Loudspeaker Transformer | 25861 | ٣ | oC | |
| 65 olims 2 " | 0 | DIO | 12 | Power Transformer | 25859 | n ๙ | 50 | |
| 5U ohms 1 | - | EII | I OHDSPEAKEPS | , | ||||
| APACITOPS | 13 | |||||||
| 101 | / x 5 inch Permanent Magnet | 20922 | ||||||
| -20 μμF Trimmer | 19659 | ر ری | 152 | 12 Inch Permanent Magnet | 20933 | |||
| 000 μμF padder 2 | 20 | 561 | o inch Permanent Magnet | 20766 | ||||
| l-20 μμF Trimmer | 19656 | 5 | SWITCHES | |||||
| 10 μμF mica | _ | F6 | SI | Phono-Radio Switch | 26000 | č | ||
| 2-445 μμF tuning | 18674 | _ | C4 | S2 | Power Switch (on R15 R16) | 04000 | 50 | |
MECHANICAL REPLACEMENT PARTS
| ltem | Part No. | |
|---|---|---|
| Bracket Assembly (Ferrite Aerial) | 34500 | |
| Bracket, Pulley Assembly | 33994 | |
| Bracket, Tuning Spindle | 33387 | |
| Cabinet, 776-GA | 23129 | |
| Capinet, 778-GA Receiver | 23130 | |
| Cabinet, 778-GA Speakers | 28132 | |
| Clip (Retaining L.F.'s) | 27780 | |
| Clip (Retaining Phone Motor Sacket) | 21915 | |
| "C" Clip (Retaining Pulley No. 7885) | 2537 | |
| "C" Clip (Retaining Pulley No | ||
| 17716) | 4885 | |
| Dial Scale | 32244 | |
| Drive Drum Assembly | 34123 | |
| Grommet (Gang Mounting) | 33339 | |
| Handle 776-GA (Turner Style p36 / | ||
| Knop moulded (Base and Tuning | ||
| Controls) | 34133 | |
| Knop moulded (Power - Treple | ||
| Control) | 35157 | |
| Knon moulded (Phono Radio | ||
| Switch) | 35158 | |
| Knop, disc (Volume Control) | 24535 | |
| Knop, door 778-GA (Satin Brass- | Cude 1.5. 42302 | 4 |
| Knop, door 778-GA Satin Chrome | Code No 42302 | 5 |
| Lever Assembly Receiver Compart- | ||
| ment. Bronze | 53176 | |
| Lever Assembly Receiver Compart- | ||
| ment. Chrome | 33174 | |
| Pointer Assembly | 33979 | |
| Power Cable Assembly | 34388 | |
| Puiley (Drive Cord, Large) | 7995 | |
| Pulley (Drive Cord, Small) | 17716 | |
| Pulley (Tuning Spindle) | $3365 | |
| Retainer (Cabinet Back) | 34254 | |
| Screw (Broadcast Coil Mounting | 31373 | |
| Screen, Socket Valve 7 pin | Code No. 79457- | 4 |
| Socket, Valve 7 pin | Code 'vd 79457 | ¢ |
| Socket, 2 pin | Cade No. 79303 | 3 |
| Socket, 3 pin | 31325 | |
| Socket, Phono Motor | 1 | |
| Spring, Drive Cord | 26313 | |
| 5 |
When ordering, always quote the above part or code num bers, and in the case of coloured parts epum as thoreas knocs, etc., the colour plus the part munder
D.C. RESISTANCE OF WINDINGS
| Winding |
D.C. Resistance
in ohms |
||
|---|---|---|---|
| Ferrite Aerial Assembly (M.W.). | |||
| Primary (L1) | * | ||
| Secondary (L2) | 2 | ||
| Aerial Coil (S.W.): | |||
| Primary (L3) | 2.5 | ||
| Secondary (L4) | * | ||
| Oscillator Coil (M.W.) (L7) | 3.5 | ||
| Cscillator Coil (S.W.) | |||
| Primary (16) | * | ||
| Secondary (L5) | * | ||
| ist. 2nd I.F. Transformer Windings | 17 | ||
| 3rg I.F. Transformer Windings | 12 | ||
| Elter Choke (L14) | 170 | ||
| Power Transformer (T2). | |||
| Primary | 20 | ||
| Secondary | 240 | ||
| loudspeaker Input Transformer (T1): | 2.0 | ||
| Primary | 500 | ||
| Secondary | 1 | ||
* Less than I ohm.
The above readings were taken on a standard chassis, but substitution of materials during manufacture may cause variations and it should not be assumed that a component is faulty if a slightly different reading is obtained.
SOCKET VOLTAGES
| VALVES |
Cathode to
Chassis Volts: |
Screen Grid
to Chassis Volts: |
Anode to
Chassis Volts: |
Anode
Current mA: |
Heater
Volts: |
|
|---|---|---|---|---|---|---|
| 6BE6 | Converter | _ | 85 | 170 | 2.0 | 6.3 |
| 6BA6 | I.F. Amp | 2.0 | 85 | 170 | 4.5 | 6.3 |
| 6AV6 | Det., Tone Control | |||||
| Amp., A.V.C. | 0.75 | 90 | 1.0 | 6.3 | ||
| 1 2 AX7 | A.F. Amp., Phase | 1.22 | 135 | 1.0 | ||
| 6V6GT |
Splitter
Push-pull |
55 | 205 | 0.1 | 6.3 | |
| 6V6GT | tuqtuo | 14 | 260 | 250 | 38 | 6.3 |
| 5Y3GT | Rectifier | 260 | _ |
265/265
A.C. R.M.S. |
5.0 |
Total H.T. Current | Radio = 105 → Volts across Filter Choke L14 == | Radio 4 | Phono = 90 → 1.5
Measured at 240 volts A.C. supply. No signal input. Volume Control maximum clockwise.
Voltmeter 20.000 ohms der volt. measurements taken on highest scale giving accurate reagable defection
₥ U ۵ ш I L ບ
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