Kenwood TK-230 Service Manual

External viewTK-230/230(SC)KSC-6 (COMPACT CHARGER)SpecificationsSource voltage .... 0... 0... ee 120V/60Hz (K type)220V/50,60Hz (M type)120V/50,60Hz (M2 type)Chargingcurrent.......... 00002005Approx.80mA(KNB-3)7Approx.160mA(KNB-4)Chargetime..........0.0.00eeeApprox.15 hours(at25°C)Ambienttemperature...........0.0. 5°C~40°C(41°F~104°F)Dimensions(Bodyonly)..........-.2.05"'(62mm)Wx1.65""(42mm)Dx3.31"(84mm)H:ACAdaptor3.31"(84mm)Wx3.15”(80mm)Dx3.43"(87mm)H:ChargerWeight..0.0.0...ee,,0.75lbs(340g):ACAdaptor0.79 Ibs (860g) : ChargerDesign and specifications subject to change without notice.Circuit descriptionThe KSC-6 is a compact trickle charger for chargingKNB-3A and KNB-4 batteries.‘ Charging CircuitWhen a KNB-3A is connected, current flows through R8(4782). The maximum charging current is approx. 160mA.When a KNB-3A is connected, current flows through R8(1002) and Q3 : 2SA1241Y. The current flow throughR6 to the battery is maximum approx. 100mA. Thecurrent flow to Q3 is limited by the voltage drop acrossR10, the forward voltage of diodes D4 and D5, and thebase-to-emitter voltage VVBE of Q3, as given by thefollowing formula:_ (Voltage across D4 and DO—VBE of Q3) _R10(1.2V-06V)_ 06 9272 ra mA Approx.Thus current flow to the KNB-4 in the completelydischarged state is approximately 320mA. As chargingprogresses, the value becomes lower. When KNB-3A orKNB-4 is charged, the current limiting circuit, consistingof Q2 : 2SA1241Y, D2 and D3 (output current approx.160mA) is not working.Indicator CircuitThe voltage drop across R2 and R3 turns on Q1 sothat current flows to the red CHARGING indicator inLED1.