TECHNICAL INFORMATION AND SERVICE DATA
MODELS 608-T & 706-C
FIVE VALVE, TWO BAND, BATTERY-VIBRATOR OPERATED SUPERHETERODYNE
ISSUED BY
AMALGAMATED WIRELESS (A/SIA.) LTD.
ELECTRICAL SPECIFICATIONS.
FREQUENCY RANGES .......... Medium Wave, 1600-550 Kc.
(187.5-545 M.) Short Wave, 22-7 Mc. (13.6-43 M.)
INTERMEDIATE FREQUENCY 455 Kc.
BATTERY COMPLEMENT:
There are three modes of operation—two employing "B" batteries and the third a Vibrator Power Unit.
Battery cables are available fitted with telephone tips for batteries fitted with Fahenstock clips, or with plugs for socket-type batteries.
The batteries used and their respective cables are as follows:----
Battery Operation:
Cable Cable with Tips with Plugs
- (1) I— 4 volt accumulator
- (2) I—I.5 dry cell "A" battery } 2—45 volt "B" batteries } 19182 19801
- NOTE: If a 1.5 volt dry cell "A" battery is used it is necessary, if dial illumination is required, to remove the dial lamp cable from the terminals at the rear of the chassis and to connect the cable to the outer terminals of a 4.5 volt battery—see diagram, "Battery Connections."
Vibrator Power Unit Operation:
I-4 volt accumulator. Vib. Power Unit 19190.
BATTERY CONSUMPTION-
|
4 volt "A" battery
1.5 volt "A" battery "B" battery |
|
|---|---|
| Vibrator Operation | 0.8 Amp. |
| IAL LAMP (2) | 2.0 volt, 0.06 Amp. |
|
USE:
Battery Operation Vibrator Operation |
|
|
ALVE COMPLEMENT:
(1) IA7GT Canverter (2) IP5GT I.F. Amplifier (5) IQ5G |
|
| BRATOR | A.W.AOAK Type, V6804 |
LOUDSPEAKER (Permanent Magnet)-
Model 608-T. Model 706-C.
| 7 inch Code No. AY23 | 12 inch Code No. AU25 |
|---|---|
| Transformer XA7 | Transformer TX8 |
| V.C. Impedance— | V.C. Impedance- |
| 3 ohms at 400 | 2.2 ohms at 400 |
| C.P.S. | C.P.S. |
UNDISTORTED POWER OUTPUT ...... 250 Milliwatts
* THE DIAL IS ILLUMINATED IN THIS POSITION
COCKET VOLTAGES AND CURRENTS
| Valves |
Bia:
Volt |
5 |
Screer
to C Vo |
n Grid
Chassis olts |
Anod
Cha Vo |
e to
issis Its |
Anode C
mA |
urrent |
Filament
Volts |
|
|---|---|---|---|---|---|---|---|---|---|---|
| B. | ٧. | В. | ٧. | В. | V. 1 | Β. | ٧. | |||
| LATGT Converter | ) | . 0 | 40* | 40* | 84 | 90 | 0.3 | 0.3 | 1.4 | |
| 50 | 50 | 0.8 | 0.8 | 1. 1 | ||||||
| S W | · _ · · | 75 | 75 | 1.2 | 1.1 | |||||
| IDECT LE Amplifier | ( | ) | 0 | 84 | 90 | 84 | 90 | 1.3 | 1.5 | • 1.4 |
| IPECT LE Amplifier | ) | 0 | 84 | 90 | 84 | 90 | 1.3 | 1.5 | 1.4 | |
| ) | 0 | 50* | 50* | 0.03 | 0.03 | 1.4 | ||||
| IQ5GT Output | 5* | -4.5* | 84 | 90 | 80 | 85 | 6 | 9 | 1.4 |
Measured with no signal input. Volume Control maximum clockwise.
* These readings may vary, depending on the resistance of the voltmeter used.
MECHANICAL REPLACEMENT PARTS.
| Item | Part No. | ltem | Part No |
|---|---|---|---|
| Paris Charles | Panel, terminal, 2 way | 17386 | |
| Receiver Chassis: | C73 | Insulator | 17387 |
| Cabinet, Table Model | C68 | Screen, I.F. transformer | 3351 |
| Сар | 8372 | ||
| Screen valve | 9410 | ||
| 4 Voit | See "Electrical Spe | cifications" | Can | 8148 |
| Register | 4733 | ||
| 19186 | Seclet 12 pin battony connection | ||
| 10100 | (female) | ||
| Console Model | (Terriale) — Contact accombly | 17760 | |
| Cable, Volume Control | . 19180 | Contact assembly | 17763 |
| Chassis-end— | 10172 | Dian elemping | 17764 |
| Left hand | 191/3 | King, Clamping | 17765 |
| Right hand | Clamp ashla | 17776 | |
| Clip, grid | 7459 | 4704 | |
| Control Card, celluloid— | 10545 | 7326 | |
| Left hand | . 19545 | 10012 | |
| Right hand | 19546 | Spindle, tuning arive | 4441 |
| Dial frame assembly | 19622 | Spring, arive tension | 7420 |
| Dial lamp assembly | 10224D | Strip, tag, I-way | 0040 |
| Dial scale | 19032 | Z-way | 4251 |
| Drum, drive | 9090 | 3-way | 4251 |
| Dust cover, 7 inch loudspeaker | 9843 | 5-way | 9210 |
| 12 inch loudspeaker | 10306 | /-way | 98/9 |
| Knob, small | 4589 | Vibrator Power Unit No. 19190: | 10512 |
| large | Cable, battery | 17312 | |
| Mount plate assembly, tuning driv | e 19011 | Socket, vibrator | 17510 |
| Plug, 12 pin, battery connection (male | ) 17757 | Strip, tag, Z-way | 19511 |
| Pulley brass | 1730 | 2-way, with lug | 8021 |
Tuning Drive Cord Replacement.
The accompanying diagram shows the route of the cord and the method of attachment. Whilst fitting the cord, keep it taut and adjust the length so that the tension spring measures approximately 2 inches long when fitted. The spring should be sheathed to prevent it from rattling against the drum.
D.C. RESISTANCE OF WINDINGS.
| Winding | D.C. Resistance in ohms |
|---|---|
|
Aerial Coil (M.W.)—
Primary (L2) Secondary (L3) |
10.5
3.5 |
|
Aerial Coil (S.W.—
Primary (L4) Secondary (L5) |
2
* |
|
Oscillator Coil (M.W.)—
Primary (L6) Secondary (L7) |
l
6 |
|
Oscillator Coil (S.W.)—
Primary (L8) Secondary (L9) |
|
| I.F. Transformer Windings | 7.5 |
| I.F. Filter (LI) | 17.5† |
|
Smoothing Choke (L16)
Smoothing Choke (L75) R.F. Filter Choke (L17, L73, L74) R.F. Filter Choke (L71, L72) |
*
200 * 9 |
|
Loudspeaker Input Transformer (TI)—
XA7 Primary XA7 Secondary TX8 Primary TX8 Secondary |
650
* 430 * |
|
Vibrator Transformer (T71)—
Primary Secondary |
•
300 |
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.
* Less than I ohm.
† In some receivers this reading may be as high as 60 ohms.
| Order |
Connect "high" side
of Generator to: |
Tune Generator
to: |
Set Receiver Drive
Drum Scale to: |
Adjust for Maximum
peak output: |
|---|---|---|---|---|
| IA7GT Grid* | 455 Kc. | 0† | LI4 Core | |
| 2 | IA7GT Grid* | 455 Kc. | 0 | LI3 Core |
| 3 | IA7GT Grid* | 455 Kc. | 0 | LI2 Core |
| 4 | IA7GT Grid* | 455 Kc. | 0 | LII Core |
| 5 | IA7GT Grid* | 455 Kc. | 0 | LIO Core |
| Repeat the above adju | ustments until the maximum | output is obtained. | ||
| 6 | Aerial Terminal | 600 Kc. | 18 | L.F. Osc. Core Adj. (L7)‡ |
| 7 | Aerial Terminal | 1500 Kc. | 154 | H.F. Osc. Adj. (C5) |
| 8 | Aerial Terminal | 1500 Kc. | 154 | H.F. Aer. Adj. (C3) |
| Re | peat adjustments 6, 7 and | 8. | ||
| 9 | Aerial Terminal | 20 Mc. | 157 | H.F. Osc. Adj. (C8)§ |
| 10 | Aerial Terminal | 20 Mc. | 157 | H.F. Aer. Adj. (C4)¶ |
ALIGNMENT TABLE.
* With grid clip connected. A 0.001 uF capacitor should be connected in series with the "high" side of the test instrument. † Set right-hand edge of pointer at 0, with tuning capacitor plates fully meshed.
‡ Rock the tuning control back and forth through the signal.
Suse minimum capacity peak if two can be obtained. Check to determine that C8 has been adjusted to correct peak by tuning the receiver to approximately 19.09 Mc., where a weaker signal should be received.
¶ Use maximum capacity peak if two can be obtained.
Loudspeaker Service.
It is inadvisable to attempt loudspeaker repairs other than adjustment of the voice coil and replacement of the transformer. The fitting of a new cone or the replacement of a field winding should be done only by Service Departments suitably equipped to do the work.
To centre the voice coil first remove the dust cover. To do this, use a very sharp razor blade and cut the centre out of the dust cover, cutting just inside the edge of the voice coil former, which can be felt with the finger. Do not attempt to tear the cover from the cone. Loosen the suspension screws, insert three narrow paper "feelers" in the gap and re-tighten the suspension screws. The "feelers" should be approximately 3/16 inch wide and 0.006 inch thick.
After adjusting, test the loudspeaker, and, if satisfactory, fasten a replacement dust cover in place with latex rubber cement. (See "Mechanical Replacement Parts.")
"Service Window."
A "Service Window" is provided in the base of the table model cabinet. The "Window" is normally covered with a perforated grille fastened by four knurled nuts. With the grille removed, it is possible to perform most servicing operations without removing the chassis from the cabinet.
Chassis Removal and Replacement.
Remove the control knobs. The knobs on the front of the cabinet are each held by a set screw. To remove the Tuning Control knob at the side of the cabinet, proceed as follows:—
Table Model: The knob pulls straight off.
Console Model: Loosen the screws in the spindle coupling and part the spindle.
- (2) Disconnect the pointer from the dial drive cord, by unscrewing the thumb nut, and disconnect the cable from the loudspeaker. Also, disconnect the yellow and black dial lamp leads from the chassis.
- (3) Four bolts hold the chassis in the cabinet. Remove these and withdraw the chassis.
On replacing the chassis in the cabinet, care must be taken to connect the dial pointer correctly, as follows:------------------------------------
- (1) Turn the Tuning Control fully anti-clockwise.
- (2) Bring the dial pointer to a position opposite a setting mark on the dial scale, below, and approximately 1/16 inch to the left of 2CR.
- (3) Connect the pointer to the top drive cord and tighten the thumb-screw.
MECHANICAL SPECIFICATIONS.
| Height | Width | Depth | Height | Width | Depth | ||
|---|---|---|---|---|---|---|---|
| Cabinet Dimensions (inches)- | - | Carton Dimensions (inches)- | 05 | 10 | |||
| 608-T |
||
|
23
|
108 | 706-C |
12
35 |
32 |
12
14 |
| 706-C | 33울 | 30 | 13 | Weight (nett lbs.)— | - | ||
| Chassis Base Dimensions | 3 | 15 |
6
|
608-T
706-C |
30
. 70 |
||
| Overall Chassis Height (inches) | . 8 | Cabinet Finish | ••••••••••••••••••••••••••••••••••••••• | Walnut | Veneer |
GENERAL DESCRIPTION.
The Models 608-T and 706-C are table and console models, respectively, and employ the same chassis. They may be either battery or vibrator operated, and for battery operation either a 4-volt accumulator, or 1.5-volt dry-cell "A" battery may be used, the necessary circuit modification being effected by the battery cable employed.
Battery connections are shown in the accompanying diagram.
Design features include: Tropic-proof construction, automatic volume control, straight-line, edge-lighted dial, with Metropolitan stations printed in 1-inch high characters; Magnetite cores in I.F. transformers and broadcast oscillator coil, air-dielectric trimming capacitors, broadcast tuning range extended to 1600 Kc. to permit reception of proposed stations above 1500 Kc.
BATTERY CONNECTIONS.
ALIGNMENT PROCEDURE.
Manufacturer's Setting of Adjustments.
The receiver is tested by the manufacturers 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 below.
Under no circumstances should the plates of the ganged tuning capacitor be bent, as the unit is accurately aligned during manufacture and cannot be re-adjusted unless by skilled operators using specialised 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.
- (I) A.W.A. Junior Signal Generator, type 2R3911
- (2) A.W.A. Modulated Oscillator, type J6726.
If the modulated oscillator is used, connect a 0.25 megohm non-inductive resistor across the output terminals, and, for short-wave alignment, an additional 400 ohms non-inductive resistor in series with the "high" output lead of the instrument.
(3) Output Meter.
The instrument recommended should have an output impedance of 12,000 ohms and a range of 5-3,000 milliwatts. The meter should be connected across the primary of the loudspeaker transformer with the voice-coil of the loudspeaker open-circuit.
If the output meter used is one which does not impress a load on the anode circuit of the output valve, it will not be necessary to open-circuit the voice-coil.
CIRCUIT CODE
|
Circuit
Code No |
Stock Code
. Description or Part No. |
Circuit
Code No. Description or Part No. Code N |
Stock Code
lo. Description or Part No. |
|---|---|---|---|
| INDUCTORS. | CI7 II5 uuF silvered mica 226, 257 | RESISTORS. | |
| LI | I.F. filter choke (in- | CI8 I30 uuF silvered mica 226, 265 RI | 400 ohms, ½ watt 600, 273 |
| L2, L3 | Aerial coil, 1600-550 |
Cl9 0.1 uF paper, 400 V. R2
working 228, 121 |
40,000 ohms, I watt
600, 513 or 600, 713 |
| Kc. 7974 | C20 0.05 uF paper, 400 V. R3 | 0.1 megohm, ¼ watt 600, 121 | |
| L4, L5 | Aerial coil, 22-7 Mc. 9569 | working 228, 115 R4 | 63,000 ohms, I watt |
| L6, L7 |
Oscillator coil, 1600-
550 Kc. 7638 |
C21 0.5 uF paper, 400 V.
working 228, 135 R5 |
800, 517 or 600, 717
5000 ohms, I watt |
| L8, L9 | Oscillator coil, 22-7 | C22 II5 uuF silvered mica 226, 257 | 600, 495 or 600, 695 |
| Mc. 9570 | C23 130 uuF silvered mica 226, 265 | 400 ohms, ½ watt 600, 273 | |
| C24 0.05 uF paper, 400 V. | 0.1 megohm, ¼ watt 600, 121 | ||
| 2nd I.F. transformer 56882, 5689* | working 226, 115 R8 | 1.6 megohms, ‡ watt 600, 145 | |
| LI4, LI5 | 3rd I.F. fransformer 59592, 5758* |
C25 20 uF, 200 P.V. elec- R9
trolytic EE10725 P10 |
50,000 ohms, 4 watt 600, 115 |
| LI6 | Smoothing choke 8243 | C26 100 uuF mica 224, 261 | Control 10176 |
| L17 | R.F. choke 3149 | C27 70 uuF silvered mica 226, 460 R11 |
10 megohms, 1 watt
600 561 or 600 761 |
| 172 | C28 100 uuF mica 224, 261 R12 | I megohm, I watt | |
| C29 0.01 uF paper, 600 V. | 600, 541 or 600, 741 | ||
| L/3 | C30 400 uE 12 PV elec |
0.2 megohm, 1 watt
600, 527 or 600, 727 |
|
| L/4 | R.F. choke 3149 | trolytic ET1045 R14 | 0.5 megohm, ½ watt 600, 135 |
| L/5 | K.F. choke 8321 | C31 0.1 uF paper, 400 V. RI5 | 10,000 ohms, 4 watt 600, 101 |
| CAPACITORS. | working 228, 121 R16 | 56 ohms, wire wound, | |
| CI | 50 uuF silvered mica 226, 155 | C32 100 uuF mica 224, 261 | 3 watt 610, 556 |
| C2 |
•
4 uuF mica 224, 233 |
C33 0.01 uF paper, 600 V. N17
working 228, 301 |
W.W. + 5% 610, 526 |
| C3 | 2-20 uuF air trimmer 3661 | C34 0.0025 uF paper, 600 R18 | 500 ohms, ‡ watt 600, 075 |
| C4 | 6-24 uuF air trimmer 5435A | V. working 228, 289 R19 | 0.5 megohm, ¼ watt 600, 135 |
| C5 | C35 0.02 uF paper, 600 V. R20 | 500 ohms, 🛓 watt 600, 075 | |
| CL | C24 01 | 7 ohms, 3 watt, W.W. 610, 507 | |
| 2½% (padder) 13212† | working 228, 121 | 150 ohms, I watt, W.W. 610, 105 | |
| C7 | 0.05 uF paper, 400 V. | C37 400 uF, 12 P.V. elec- | TRANSFORMERS. |
| C 0 | working 228, 115 |
Loudspeaker trans-
former (table model) XA7 |
|
| 2-10 uur air trimmer 3658 | working 228, 301 | Loudspeaker trans- | |
| C9 |
4000 uuF mica,
+
2½% (padder) 13213† | |
C72 0.02 uF paper, 600 V. | former (console model) TX8 |
| C10 | 0.05 uF paper, 400 V. | working 228, 307 [77] | Vibrator transformer 17568 |
| working 228, 115 |
C73 0.02 uF paper, 600 V.
working 228, 307 |
SWITCHES. | |
| CII |
12-430 uuF variable
tuning (ganged) 19175 |
C74 0.1 uF paper, 400 V. SI | Range, 2 wafer, 2 posi- |
| CI2 | 12-430 uuE variable | working 228, 121 | Battery Lwsfor 3 pos: |
| tuning (ganged) 19175 | C75 0.01 uF paper, 600 V. vorking 228, 301 | tion, rotary 19177 | |
| C13 |
20 uF, 200 P.V. elec-
trolytic EE10725 |
C76 0.1 uF paper, 400 V. |
lone, I wafer, 3 posi-
tion, rotary 19178 |
| C14 | 50 uuF mica 224, 255 | FUSES. | |
| CI5 | 0.1 uF paper, 400 V. |
C// 0.01 uF paper, 600 V.
working 228, 301 F71 |
Cartridge, 3 Amp. 370, 011 |
| working 228, 121 | C78 20 uF, 200 P.V. elec- | Cartridge, 4-3 Amp. 370, 004 | |
| C16 | 0.5 uF paper working 228, 135 | trolytic EE0839 F73 | Cartridge, 4-8 Amp. 370, 004 |
* Part number of winding only.
+ Capacitance and tolerance (if shown) to be guoted.
CIRCUIT DIAGRAM
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