Onkyo-TXSR502-avr-sb04003 电路图 维修手册.pdf

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1、 SERVICE BULLETIN NO:04003 2004/04/21 MODELS : TX-SR502/502E/8250/HT-R520 SUBJECT : The countermeasure against IC oscillation. Symptom: TX-SR502s output sometimes has a hum with signals after power on within few minutes. When selector or DSP mode is switched to another at this moment, the protect pr

2、ogram starts. Cause: Oscillatation of IC regulator. Procedure for service: To exchange an electrolytic capacitor with that of 330uF for C6412 in NADG- 8230. Circuit No. Before change After change Parts No. Description Parts No. Description C6412 394741007 ELECT C CE04W16V10M 394743317 ELECT C CE04W1

3、6V330M Marking: No change Application: TX-SR502(B) MDD, MDC HT-R520(B) MDD, MDC #1- HT-R520(S) MDD, MDC #1- RadioFans.CN 收音机爱 好者资料库 TX-SR502 SERVICE BULLETIN No.04003 The countermeasure against IC oscillation. bend cut hook IN OUT heat sink 1 Electrolytic Capacitor 330uF 16V 394743317 2 3 4 Q6406 IN

4、 OUT heat sink C6412remove solder solder fix with bond 5 side Front Preamplifier PC board NADG-8230 side heat sink GND TOP VIEW TOP VIEW 8 7 6 Q6406 heat sink disconnect P7502 P7502 P7502 connect 9 Visual Check 1. Check if the capacitor is properly connected to the IC considering polarity. 2. Check

5、if soldering was done by using just enough quantity of solder and heat and there remains enough clearance between the capacitor and the other terminals or heat sink nearby. 3. Check if just enough bond is used to fix the capacitor and no bond is left around socket. 4. Check if FFC of P7502B is inserted in the socket in the right direction from the right angle. Operation Check Check if sound outputs properly when digital sound signal is input. RadioFans.CN 收音机爱 好者资料库