ELECTRICAL SPECIFICATIONS.
| FREQUENCY RANGES: | VIBR | |
|---|---|---|
| Medium Wave |
540-1600 Kc/s.
(555-187.5M.) |
VIBR |
| Short Wave | ||
| INTERMEDIATE FREQUENCY | 100 | |
| DIAL LAMPS | ||
| FUSES | 5 amp. Cartridge | |
| VALVE COMPLEMENT: | Und . | |
| (1) 6BA6 R.F. Amplifier | TONE | |
|
Amplifier, A.V.C. | •••• |
| Mo | dole 725.C 808 | -G7 | 24651 | |
|---|---|---|---|---|
| MO | Model | 808-G | 24651 and | 25380 |
| VIBRAT | OR CARTRIDG | E: | ||
| Uni | t No. 24651 | V5258 | ||
| Uni | t No. 25380 | V5123/55 | ||
| LOUDS | PEAKER (Perm | anent Magn | et): | |
| 12 | inch - Code N | lo. AU55. | ||
| Tra | nsformer — TU2 | 201 | ||
| ۷.C | C. Impedance – | – 6.5 ohms a | t 400 C.P.S. | |
| Undisto | rted Power Ou | itput—2.5 wo | atts. | |
| • | RANGE | TUNING | ||
| TONE |
M.N
|
, | ||
| . ( ) ) TREB | (開) | |||
| The |
Width
30
36
36
ATOR BOWER LINUTS
725-C
MECHANICAL SPECIFICATIONS.
| Cabinet Dimensions (inches): | Height | W |
|---|---|---|
| Model 725-C | З | |
| Model 808-G | 31 | 3 |
| Model 808-GZ | 31 | 3 |
| Chassis Base Dimensions (inches) |
2
|
|
| Weight (nett lbs.): | 63 lbs. | |
| Models 808-G, 808-GZ | ||
| Cabinet Finish | Walnut Ve | neer. |
General Description.
The model 725-C is a 5 valve, two band, 32 volts D.C. operated superheterodyne.
Features of its design include: Tropic-proof construction, reatures of its aesign include: iropic-proof construction, automatic volume control, magnetite cores in I.F. trans-formers and broadcast oscillator coil, air-dielectric trim-ming capacitors, straight-line edge lighted dial scale.
Models 808-G and 808-GZ are Radio-Phonograph binations and have similar features to the 725-4. . In addition, model 808-G incorporates the Garrand RC65 Automatic Record Changer, capable of playing up to eight 10-inch and 12-inch records, mixed in any order, without attention. Model 808-GZ incorporates the Garrard attention. Model 808-GZ incorporates the Garrard RC70A Automatic Record Changer, capable of playing up to ten records of equal size—either 10-inch or 12-inch.
Depth
167
CHASSIS, TOP VIEW — 725-C, 808-G, 808-GZ.
CHASSIS, UNDERNEATH VIEW — 725-C, 808-G, 808-GZ.
ALIGNMENT PROCEDURE
Manufacturer's Setting of Adjustments
The receiver is tested by the manufacturer with precision instruments and all adjusting screws are sealed. Re-alignment instruments and all adjusting screws are sealed. Re-alignment should be necessary only when components in tuned cir-cuits are repaired or replaced or when it is found that the seeds over the adjusting scrows have been have
It is especially important that the adjustments should not be altered unless in association with the association instruments listed below
Under no circumstances should the plates of the ganged Under no circumstances snould the plates of the gangea during manufacture and cannot be readjusted unless by skilled operators using specialised equipment.
For all alignment operations connect the low side of For all alignment operations, connect the low side of the signal generator to the receiver chassis, and keep the the signal generator to the receiver chashs, and keep the generator output as low as possible to avoir n.v.c. action. Also keep the volume control in the maximum clockwise. position.
Testing Instruments
- (1) A.W.A. Junior Signal Generator type 283914 or
- (2) A.W.A. Modulated Oscillator, type J6726.
- If the modulated oscillator is used connect a 0.25 The modulated oscillator is used, connect a 0.20 merching non-inductive resistor across the output terminals and for short wave alianment, an additerminals, and, for short wave alignment, an agaithe "high" output lead of the instrument
- (3) A.W.A. Output Meter. type 2M8832.
|
Alignment
Order |
Connect "high" side
of Generator to: |
Tune Generator
to: |
Tune Receiver Dial
to: |
Adju
peak output |
|---|---|---|---|---|
| I |
R.F. Section of Gang
(centre portion) |
455 Kc/s. | 540 Kc/s. | LI4 Core |
| 2 |
R.F. Section of Gang
(centre portion) |
455 Kc/s. | 540 Kc/s. | LI3 Core |
| 3 |
R.F. Section of Gang
(centre portion) |
455 Kc/s. | 540 Kc/s. | LI2 Core |
| 4 |
R.F. Section of Gang
(centre portion) |
455 Kc/s. | 540 Kc/s. | LII Core |
| Repeat the above | adjustments until the m | aximum output is obtained | ||
|
5
6 7 8 |
Aerial Terminal
Aerial Terminal Aerial Terminal Aerial Terminal |
600 Kc/s.
1500 Kc/s. 1500 Kc/s. 1500 Kc/s. |
600 Kc/s.
1500 Kc/s. 1500 Kc/s. 1500 Kc/s. |
Osc. Core Adj. (L5)*
Osc. Adj. (C15) R.F. Adj. (C9) Aer. Adj. (C4) |
| Repeat adjustments 5, 6, | 7 and 8. | |||
|
9
10 1 1 |
Aerial Terminal
Aerial Terminal Aerial Terminal |
16 Mc/s.
16 Mc/s. 16 Mc/s. |
16 Mc/s.
16 Mc/s. 16 Mc/s. |
Osc. Adj. (C17)**
R.F. Adj. (C8)† Aer. Adj. (C5)† |
ALIGNMENT TARLE
*Rock the tuning control back and forth through the signal.
**Use minimum capacity peak if two_can be obtained. Check to determine if C17 has been adjusted to correct peak by tuning the receiver to approximately 15.09 Mc/s. where a weaker signal should be received.
tUse maximum capacity peak if two can be obtained
Connection to Power Supply.
The receiver will not operate unless it is connected to the power point in the correct polarity. It is necessary, therefore, that all power points to which the receiver may be connected are wired with the same polarity. The plug should be wired to the receiver power cable so that the red wire connects to the positive side of the supply and the black wire to the negative side.
A warning is given on the use of "Double Adaptors." which normally have one outlet connected in the reverse polarity to the other. If the use of a "Double Adaptor" is essential, the outlet with the correct polarity only should be used for the receiver.
Interference Suppression
The receiver has a filter unit built in to suppress any interference entering the receiver via the power supply. If, however, the receiver is in operation whilst the motor generator is running, some further form of suppression will averally be necessary to reduce interference which is radiated from the generator and picked up by the receiver aerial.
It is recommended that the following be carried out:-To each generator brush connect one end of a 0.5 uF
capacitor. Then connect the other ends of the capacitors to the generator housing.
The generator housing should be earthed, using a wire as short as possible and of not less than 7/.029 insulated cable. Chassis Removal.
First remove the control knobs. Each knob is held by a set screw. Then, disconnect the Loudspeaker, Vibrator, and in the case of models 808-G and 808-GZ, the Pick-up Cables
The chassis is held in the cabinet by four nuts, two at each end of the dial frame assembly. Removal of these enables the chassis to be withdrawn from the cabinet.
Dial Pointer Adjustment.
The dial pointer is held in position on the drive cord by two rubber-lined clips. To alter the position of the pointer, loosen the two holding clips slightly and move the pointer in the required direction. It is important to reclamp the clips after any adjustment of the dial pointer.
Drive Cord Replacement.
Follow the diagram which is affixed to the back of the dial frame assembly. This shows the route of the cord and the method of attachment
VIBRATOR POWER UNIT No. 24651 MODIFICATION.
Some trouble has been experienced on these Vibrater Power Units due to vibrator contact flash over on starting. The following modification has been well tried in the field and is recommended as a worthwhile contribution towards more reliable performance
The change consists of removing the two secondary buffer condensers C3 and C4 (refer Vibrator Power Unit Circuit) and replacing them with two 0.5 µF 400v. paper condensers connected in parallel across the primary of the vibrator transformer, i.e., from pin I to pin 5 of the vibrator socket.
Due to the size of the 0.5 µF condensers, they will not fit under the chassis but must be placed beside the trans-
former on top of the chassis and suitable connection arrangements made. (See photograph below.)
In some units resistor R2 is a 5 ohm 3 watt and is mounted below the chassis, in other units resistor R2 is a 5 ohm 5 watt resistor and is mounted above the chassis, but must be moved to the position shown in photograph below to enable the two 0.5 µF 400v. paper condensers to be fitted.
It is also recommended that when a replacement of a vibrator cardridge is necessary and Oak type V6732 be used. As this vibrator has a 32 volt driving coil, it is essential to remove the coil dropping resistor R1. (Refer Vibrator Power Unit Circuit.)
No. 24651.
VIBRATOR POWER UNIT No.25380
D.C. RESISTANCE OF WINDINGS.
| Winding | D.C. Resistance in ohms |
|---|---|
| Aerial Coil (M.W.) | |
| Primary (LI) | 16 |
| Secondary (L2) | 5 |
| Aerial Coil (S.W.) | |
| Primary (L6) | 4 |
| Secondary (L/) | * |
| R.F. Coll (M.W.) | 50 |
| Primary (L3) | 50 |
| Secondary (L4) | 6 |
| R.F. Coil (S.W.) | - |
| Primary (L8) | 5 |
| Secondary (L9) | 7 |
| Oscillator Coil (M.W.) (L5) | / |
| Uscillator Coll (S.W.) (LIU) | 4 |
| DECLESTICE | · * |
| K.F. Choke (LIS, LI7, LI8) | 200 |
| H.I. Filter Choke (LIO) | 200 |
| 345 | |
| Frimary | * |
| Vibrater Power Units No. 24651 & | |
| 25200 | |
| PE Choka (11 12) | + |
| R.F. Choke (13) | 9 |
| Vibrator Transformer (T1) | , |
| Priman | * |
| Secondary | 180 |
| Vibrator Transformer (T2) | |
| Primary | 5 |
| Secondary | 20 |
| 1 20 |
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.
MECHANICAL REPLACEMENT PARTS.
| ltem | Part No. | ltem | Part No. |
|---|---|---|---|
| Cabinet, Model 725-C | C86Z | Knob | 4589 |
| Model 808-G | C82X | Socket, Valve Ass. (miniature) | 15919 |
| Model 808-GZ | C92Y | Socket, Valve Ass. (miniature) | 24757 |
| Cable, Pick-up | 2 4 637 | Socket, Valve Ass. (miniature) | 25394 |
| Cable, Speaker | 19188 | Socket Valve (Octal) | 4704 |
| Chassis, End. Right-hand | 20316 | Strip Tag I way | 7628 |
| ,, ,, Left-hand | 24760 | Stip, idg i way | 22045 |
| Dial Frame Assembly | 20343K | Γ ωαγ | 22945 |
| Dial. Pointer Assembly | 20331 | 5 way | 9210 |
| Dial Scale | 25953A | 7 way | 19920 |
| Drum, Drive | 15684 | Terminal, Spring | 5458 |
SOCKET VOLTAGES.
| VALVES |
Cathode to
Chassis Volts |
Screen Grid
to Chassis Volts |
Plate to
Chassis Volts |
Plate
Current mA |
Heater
Volts* |
|
|---|---|---|---|---|---|---|
| 6BA6 | R.F. Amp., M.W. |
0.9
0.9 |
65
65 |
200
200 |
3.3
3.2 |
6.3
6.3 |
| 6BE6 | Converter, M.W. |
65
65 |
200
200 |
1.1
1. |
6.3
6.3 |
|
|
6BA6
6AV6 6V6GT |
I.F. Amp
Det., A.F. Amp., A.V.C Output |
1.1
0 9.0 |
65
200 |
200
80** 190 |
2.0
0.5 34 |
6.3
6.3 6.3 |
Total H.T. Current 50 mA.
Measured with Receiver connected to 32 volts D.C. Supply. Volume Control maximum clockwise. Power Switch extreme clockwise. No signal input. Voltmeter 1000 ohms per volt; measurements taken on highest scale giving accurate readable deflection. Total Input Current: Model 725-C—1.3 amps.
Model 808-G-Radio 1.3 amps., Phono. 2.1 amps. Model 808-GZ-Radio 1.3 amps., Phono. 1.8 amps.
Model 808-G only-Record hanger Voltage-120 volts A.C. Measured with rectifier type meter.
*These readings are nominal and will vary, due to the Series Heater connections.
**Cannot be measured with an ordinary voltmeter.
| 808-G |
|---|
| 808-G. |
| ŏ |
| 725-C |
| 4 |
| RADIOI |
| CODE. |
| CIRCUIT |
N
| Part No. | TIDOL | 0701 | AU55 | 24799 | 10407 | ||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Description |
100 uuF Mica
0.01 uF Paper 600 v. Working |
100 uuF Mica
150 uuF Silvered Mica |
150 uuF Silvered Mica | 0.1 uF Paper 400 v. |
Working .
16 uF 525 P.V. Electro- |
lytic
0.005 uF Paper 600 v. |
Working
1500 uuF Mica |
0.01 uF Paper 600 v. |
Working
25 uF 40 P.V. Electro- |
lytic | Working | 0.005 uF Paper 600 v. | Working | Working | 200 UUF Mica | 0.4 uF Paper 200 v. |
Working
0.4 uF Paper 200 v. |
Working . | 0.4 uF Paper 200 v. |
Working
25 JiF 40 P.V. Electro- |
lytic | 12 inch Permanent | Magnet | Phono/Range Switch | FUSES | 5 amp. Cartridge | 5 amp. Carriage | ||
|
Code
No. |
C28
C29 |
0
0 0 0 0 0 0 0 0 0 0 0 0 |
C32 |
20
7 |
C35 | C36 | C37 | C38 | C39 |
c,
( |
040 | C4| | 747 | 740 | C43 | C44 | C45 | ) | C46 | C47 |
:
) |
ŀ | SI | 22 | 다 C | - 24 | |||
| Part No. |
18638
19659 |
19659 |
19659
19659 |
18638 | 18638 | 4004 | 19659 | ||||||||||||||||||||||
| Description |
0.4 megohm ½ watt
50,000 ohms ½ watt |
5 ohms 3 watt
5 ohms 25 watt CAPACITORS |
0.1 uF Paper 200 v. |
Working
4 uuF Mica |
12-445 uuF Tuning | 2-20 uuF Air Trimmer | Working | Working | 2-20 uuF Air Trimmer | 12-445 uuF Tuning |
70 uuF Mica
9 uuF Mica |
12-445 uuF Tuning | 470 uuf Padder ± 23% |
2-20 uuF Air Irimmer
4000 iuiF Padder ± |
24% | 2-20 uuF Air Trimmer | 500 uuF Mica (725-C) | 808-GZ) | 0.02 uF Paper 600 v. |
working
150 uuF Silvered Mica |
150 uuF Silvered Mica | 9 uuF Mica | VV. UF Faper 200 V. | 8 UF 525 P.V. Electro- |
lytic
0.1 uF Paper 400 v. |
Working
0.5 u.F. Paper 400 v. |
Working | 200 uuF Mica | |
|
Code
No. |
R22
R23 |
R25
R25 |
Ū | C2 | S S | 555 | 3 ( | 5 | őĈ |
20
C |
50 | CI3 | 014 |
CI5
CI5 |
C17 | 8 0 | 218 | C19 | C.20 | C2I |
C23
C23 |
C73 | C24 | C25 | ر ۲ ۲ | 720 | C27 | ||
| escription Part No. |
TORS
Coil 540-1600 |
1540-1600 Kc/s 24624
or Coil 540-1600 |
24626 |
Coil 6-18 Mc/s 15456
di 6-18 Mc/s 24624 |
or Coil 6-18 | Transformer 24622 | oke 3149 |
ter Choke 1531/A
oke 3149 |
oke 3149 | uns ∳ watt | gohn ½ watt |
onms z wan
ms ł watt |
gohn ½ watt (725-C) | ohms ½ watt |
-0, 000-02)
ohms + watt (725-C) |
ohms 4 watt (808:6, | GZ) | nms 5 watt |
ns 5 watt
ms 5 watt |
gohm ½ watt |
ohms I watt
mr L undt |
ohms 3 watt | gohms 🛃 watt | ohms ½ watt |
regohm volume
trol 7690 |
gohms
†
watt
ohms I watt |
igohm 1 watt |
igonm ½ watt
igohm Tone Con- |
25378 |
|
Code
No. |
LI, L2 Aerial |
L3, L4 R.F. Co
5. Co 5. Coillot |
Kc/s |
L6, L7 Aerial (
'8 19 R.F. Co |
LIO Oscillat | LII, LI2 Ist I.F. | LIS LIA ZNA I.F |
LI6 H.I. Fil
117 R.F. Ch |
LI8 R.F. Ch | RI 200 ohi | R2 0.1 me. | R4 100 ohi | R5 0.2 med | R5 50,000 | R6 20,000 | 808-1 | R7 12.5 of |
K8 40 ohr
R9 160 ohr |
RIO 0.1 me | RII 20,000 | R13 13,000 | RI4 I.5 me | R15 50,000 | R17 10 mec | R19 0.2 me |
R20 0.1 me
R21 0.1 me |
trol | ||
RECEIVER POWER UNIT No 24651
CIRCUIT CODE. RADIOLA VIBRATOR POWER UNITS 24651 & 25380
| Code | Code | ||||
|---|---|---|---|---|---|
| No. | Description | Part No. | No. | Description | Part No. |
| INDUCTORS | C4 | 0.02 uF Paper 600 v. | |||
| LI | R.F. Choke | 22936 | Working | ||
| L2 | R.F. Choke | 22936 | C5 | 0.1 uF Paper 400 v. | |
| L3 | R.F. Choke | 13809 | Working | ||
| RESISTORS | C6 | 8 uF 525 P.V. Electro- | |||
| RI | 100 ohms 3 watt | lytic | |||
| R2 | 5 ohms 5 watt | C7 | 1.2 uF Paper 200 v. | ||
| R3 | 100 ohms 3 watt | Working (3 x 0.4 uF, | |||
| R4 | 7 ohms 3 watt | in parallel) | |||
| R5 | 7 ohms 3 watt | C8 | 2 uF Paper 1000 v. | ||
| CAPACITORS | Working | ||||
| СІ |
0.4 uF Paper 200
Working |
۷. | C9 |
0.4 uF Paper 200 v.
Working |
|
| C2 |
0.4 uF Paper 200
Working |
v. | TRANSFORMERS | ||
| C3 | 0.02 uF Paper 600 | ν. | ΤI | Vibrator Transformer | 17894 |
| Working | T2 | Vibrator Transformer | 25130 |
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