Circuit
Contents
1. R y COIL RESISTANCES hea saraan Fig 2 Top of chassis Coil resistances are indicated hs TO BRIDCE OF SPERKER SILENCING SWITCH REAR EDLE OF CABINET FRAME AERIAL CONNECTIONS nhia ORED W INTERVALVE TRANS BLUE TO V S REO AND CACEN LEADS TO TALC WHITE TO VAIR RESISTANCES PRIMARNI 6500 MEASURE V3IS TO TAL L SECONDARY 2 680a MEASURE VA 2 T0 TALC Tours TALIO OF TO 7 TACE HF TRANS CONNECTIONS Fig 4 Connections to OUTPUT TRANSFORMER TAC PANEL RESISTANCES PRIM TACS P O 1 350 n SECITALS M N 255 wavechange switch Fig 3 Underside of chassis Connections und resistances of intervalve and output frame aerials and H F transformers are shown transformer2. C7 B7815 2 6 C18 A5747 Od RO 9d Output trans T2 DP654 17 6 knob DP1582 9d C10 A6516 9d R1 A6122 9d R10 B7825 9d W C switch 51 5 B7814 2 6 Switch knob DP1581 9d C11 B7822 1 9 R2 B7069 9d R11 B7824 9d Cabinet inc back Scale A7811 6d C12 A6516 9d R3 B7825 9d R12 B7825 9d and L W frame DE1577 25 Celluloid dise A7810 6d C13 B6869 1 R4 B7825 9d Prices are retail and subject to alteration without notice Orders must quote pari numbers indicated above IMPORTANT NOTE Enquiries concerning service manuals should he addressed to Head Office orders set repairs and service correspondence will be handled by the depot in whose area you are located SERVICE E K COLE LTD EKCO WORKS SOUTHEND ON SEA Telephone Southend 49491 Scottish Service Depot 27 Cadogan Street Glasgow C 2 Telephone Central 5357 8 9 Manchester Service Depot Bombay House 59 Whitworth Street Telephone Central 67 11 2 Goods address 7 Bombay Street Bristol Service Depot 14 Redcross Street Telephone Bristol 22269 Component 100 00 2 suna ay sSHOUN UV OFF POSITION 1 T02 2 CREEN 10 L2 3 CRCEN TD Ci STATOR 4 BLUE TOLI 5 707 6 TO BLACK LEAD OF THE BATTERY CABLE 7 CHASSIS 8 BLANK 9 70 JUNCTION L3iL4310 10L4 AND CERE BLANK 12 10 C3 URITETOL 2 WHITE TO TAGE SUITCH CONNECTIONS i RSs To FRC ee eT VUGRID ne ee
3. SERVICE MANUAL Price 6d CONFIDENTIAL For the Information of Ekco Registered Dealers only NOT TO BE COPIED MODEL P 148 PORTABLE RECEIVER GENERAL DESCRIPTION Model P148 is a battery operated light weight portable using four Mullard valves Valves VI H F amplifier VP2B H F pentode V2 Icaky grid detector PM2HL triode V3 L F amplifier PM2HL triode V4 output valve PM22A output pentode Accessories H T hattery Drydex H1146 Accumulator Exide JSK2 Consumption H T 7 m a L T 5 amp CIRCUIT DETAILS Frame aerials LI ALW and L2 W are switched separately between grid and filament of V1 which is trans former coupled to V2 C1IR and R3 ensure smooth reaction V2 is resistance capacity coupled to V3 V3 transformer coupled to V4 Headphone sockets are connected across primary of output transformer T2 in anode circuit of V4 Speaker silencing switch provided e Bias for V1 and V3 is developed across R10 and for V4 across RIO and RII in common H T negative line VALVE VOLTAGE AND CURRENT READINGS Valve Type Anode VP2B Voltages measured on high resistance meter Chassis e TATTA ee ee negative i v2 Voltage readings for V1 V2 and V3 depend on meter V3 PM2HL 63v 5 ma resistance Current readings are more reliable Bias measured with receiver switched on and all valves V4 2 j in sockets Resistances All resistances are indicated in Figs 1 4 Re
4. ganging Tunc receiver preferably during daytime to a station hetween audible with maximum reaction does not rotate on turntable If pointer reads incorrectly loosen centre screw and move celluloid disc through appropriate angle Note Trimmer was fitted to C8 in early receivers This should be left fully unscrewed Under chassis service Moulded escutcheon an be removed for servicing underside of chassis Remove cabinet back batteries valves station scale and control knobs two grub screws in large knob The escutcheon is held by two screws yellow washers one inch from base of cabinet and two nuts under top of cabinct If necessary screws holding chassis corners may be removed allowing chassis to be fully exposed Note Ensure that pointer indicates correctly when remounting celluloid disc Speaker If speaker requires service remove baffle output transformer and speaker complete otherwise silk may be damaged in remounting speaker i 220 and 300 metres which is only just Adjust gang trimmer C2 for maximum volume meanwhile cnsuring that receiver PRICE LIST Gang C1 C2 C8 C7813 10 6 Escutcheon F7802 4 6 C3 A384 1 C14 A4109 1 RS B7825 Qd M W frame L1 D P1580 3 green or red C4 DP1600 9d C15 A3844 1 R6 a Od H F trans 1 3 6 D P1569 5 Speaker 17803 17 6 C5 A3844 1 C16 A4109 1 R7 Od Intervalve Tuning knob DP1583 2 C6 B7822 1 9 C17 B7821 1 9 RR 9d transformer T1 DP1566 3 6 Vol control
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