Kenwood CS-5230 Service Manual

Also see for CS-5230: Instruction manual

CIRCUIT DESCRIPTIONVERTICAL PREAMPLIFIER UNITCH1, CH2Each of the CH1 and CH2 inputs passes through an AC/DC/GNDswitch and enters the 1st attenuator (1/1, 1/10, 1/100).The 1stattenuator is used in combination with the 2nd attenuator(1/1, 1/2, 1/4, 1/10) and the 5-fold function of the 2nd amplifier,to switch the 12 vertical ranges.The head amp is composed of Q102 and U101 (Q202 and U201)and isa 1/1 buffer amp with an input impedance of 1 megohmsand used for conversion of impedance. Q102 (Q202) is thesource-follower. This head amp is installed between the 1st and2nd attenuators.Starting from the 2nd amp, this unit takes the differentialamplifier configuration. The functions of U102 (U202) includethe variation and inversion functions. The variation functionallows to vary the gain continuously according to the voltageapplied to pin 5. The inversion function allows to invert the phaseaccording to thevoltages applied to pins 6 and 7. As this functionis provided only for CH2, CH1 is fixed. At the CH2 side, switchis done by Q215.Q103 (0203) is the regulated current supply forU102 (U202).Q106 and Q107 (Q206 and Q207) form an emitter-groundedamp.Q108 to Q111 (Q208 to Q211) form the cascode amp of thedifferential amp. The vertical position can be moved by regulatingthe current applied to the emitter of Q111 (Q211) based on thepanel operation.CH3With CH3, the attenuator is fixed. The signal impedance isconverted by the buffer amp of source follower Q303 andregulated current supply Q304 and the signal is sent to emitter-follower Q305. Q305 is the signal side input stage of thedifferential amp.Emitter-follower 306 is the input stage of a constant-potentialdifferential amp.The outputs from Q305 and Q306 are input to the differentialtype cascode amp formed by 0307, 0308, 0310 and Q311. Thecurrent of the cascode amp is determined by regulated currentsupply Q309. The vertical position can be moved by regulatingthe current applied to the emitter of Q311 based on the paneloperation.Channel selector, delay line drive‘As for the outputs from the position amps of the channels, onlythe signal of thechannel with which the cathodes of CH1 -D104,D105, CH2 - D204, D205, CH3 - D301, D302, D304, D305 areturned “H” by the signals from V-MODE LOGIC is sent throughCH1 - D103, D106, CH2 - D203, D206, CH3 - D303, D306 andtransmitted to the delay line driver.Q2 and Q3 form a feedback amp. Q1 lets the excessive biascurrent flow when CH1 or CH2 is in ADD mode.Trigger amp, trigger selectorWith CH1 (CH2),the differential outputs from U102 (U202) are inputto the emitter-followers Q152 and Q153 (0252 and 0253), whereQ153 (Q253) forms a cascode amp with 0114 (Q214).With CH3, the signal after the buffer amp is sent through thebuffer of emitter-follower 0314, feedback amp Q312 an outputas current from the collector of emitter-follower 0313.Only the signal of the channel with which the cathode of CH1 -D108, CH2 - D208, CH3 - D308 is turned “H” by the signal fromthe trigger controller is sent through CH1 - D107, CH2 - D207,CH3- D307 and output as current to the Horizontal unit. Q31 theexcessive bias current flow when CH1 or CH2 is in ADD mode.CH1 OUTThe CH1 outputis sent from the collector of Q152, through emitter-follower Q51 and output at CH1 OUT of the Final unit.Trigger controllerThe data on the trigger source set on the panel is input to pin 1of U1 and ”H” or “L" is output at pins 4 to 8 according to the setstate.U2 is used to switch between the data from U1 and the CRTdisplay data of each channel from V-MODE LOGIC. If the currentmode is not V mode, the former data is selected. If the currentmode is V mode, the latter data is selected for use in controllingthe trigger selector.Among CH1 - U2 pin 7, CH2 - U2 pin 9, CH3 - U2 pin 12, theterminal set with the panel is turned “H”".V-MODE LOGICU3 and U4 generates a signal synchronized with the displaychannel select signal from the panel and the end of horizontalsweep, anda signal for controlling the channel selector based onthe CHOP signal. (Figure 1)Q34 cuts off the power supply to U4 only at the instant thechannel switch is pressed, in order to prevent malfunction.Vertical range converterU401, U403, $102 and $202 output the vertical range, CAL andUNCAL data by turning them into analog values using an opampfor use as the R/O data. (Figures 3, 4)Horizontal range converterU402 and $401 output the horizontal range data using an opamp,as analog values for R/O data. (Figure 5)U404 (for main sweep), U405 (for sub-sweep) and S401 areused to switch the reference voltage for letting the sweepcurrent of the 1-2-5 steps of horizontal sweep flow. (Figure 2)FINAL UNITFinal amplifierThe signal sent from the vertical preamp through the delay lineis input to the feedback amp of Q1 and Q2. During A ALT Bsweep, the variation of the vertical position of sweep B iscontrolled by the current applied to the base of Q2 based on thepanel operation.Q3, 4, Q105, Q106 and U1 are used to amplify the vertical signal|