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Model No.: HTS-797AS 
Version: 1.0 
 

   

 
 

VFD control part 

 
 
 
 
 
 
 

Summary of Contents for HTS-797AS

Page 1: ...Home Theatre System Service Manual ...

Page 2: ... 2 Model No HTS 797AS Version 1 0 MODEL HTS 797AS ...

Page 3: ... 3 Model No HTS 797AS Version 1 0 CONTENTS SPECIFICATION 4 TYPICAL PROBLEMS PROBLEM SHOOTINGS 5 CIRCUIT DIAGRAM 11 EXPLODED VIEW 19 ...

Page 4: ...uage operation system Karaoke system Multiple Measures of protection anti interference 20 kinds of DSP Modes optional Large VFC window Amplifier 500 W x 490 D x 225 H mm Front speakers 1090 W x 432 D x 320 H mm Centre surrounds 610 W x 426 D x 224 H mm Output power 2 x 80W 1 x 30W 2 x 20W ...

Page 5: ... refer to Figure 8 4 if 5V voltage is stable then basically the problem is not caused by the power supply and CPU together with its sub circuit should be checked If the 5V voltage can not be detected pin 1 of U203 should be checked There should be an about 10V voltage is the pin is normally working otherwise it is probably the safety resistor R206 2R2 0 5W is blowout or burndown of the transformer...

Page 6: ...o large or no voltage could be detected in the circuit the power supply circuit should be mainly checked All the matters concerning power supply are all OK then CPU and its drive circuit should be considered The fragile parts of the display drive circuit are VFD901 HL D005A and IC U901 UPD16311 If the problem remains after the confirmation of the power supply and display drive circuit then I O por...

Page 7: ...ormal Whether U701 35 is high level YES YES NO YES YES NO YES NO NO YES NO NO YES NO There is no signal output t take DVD channel for example Switch to DVD channel U801 3 13 to see if there is output Whether U801 7 16 6V power supply is normal Check 6V power supply circuit Whether U801 Select A is 0V and Select B is 5V The signal s check circuit has problems Check the compare Circuits Check the ou...

Page 8: ...hether the base jointing point of Q513 and Q514 is between 0 4 to 0 6v If so then we can install the amplifier tubes again Otherwise we cannot install until the problem is solved Trouble shooting way for turning on protection trouble Phenomenon The machince s display is normal after turning on but automatically turns off when initialization is finished Analysis It approves that the turning on and ...

Page 9: ...s in this channel that has been punctured and whether the output resistance of the amplifier tube transmitter is at the open state Trouble shooting way of the protection circuit itself having problems After confirming the over current and voltage circuit both work normally but the problem cannot solved this time we need to consider the protection circuit may have problems The checking steps can be...

Page 10: ...nd thers is no output either Analysis Because this unit only has one main transformer to supply the power so after it is turned on the power which display part and CPU s work need has been added That is the display has no realation with the circuit of the main power relay What is affected is the amplifier s power supply is lacking so there is no output or the output is very small Trouble shooting ...

Page 11: ... 11 Model No HTS 797AS Version 1 0 CIRCUIT DIAGRAM CPU control part ...

Page 12: ... 12 Model No HTS 797AS Version 1 0 VFD control part ...

Page 13: ... 13 Model No HTS 797AS Version 1 0 Karaoke signal conduction part ...

Page 14: ... 14 Model No HTS 797AS Version 1 0 Power supply part ...

Page 15: ... 15 Model No HTS 797AS Version 1 0 ...

Page 16: ... 16 Model No HTS 797AS Version 1 0 Amplifier part ...

Page 17: ... 17 Model No HTS 797AS Version 1 0 Channel selection part ...

Page 18: ... 18 Model No HTS 797AS Version 1 0 Volume adjustment part ...

Page 19: ... 19 Model No HTS 797AS Version 1 0 EXPLODED VIEW ...

Page 20: ......

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