The fault plane switching channels in an instant sound and image normal , indicating that the data storage units when the CPU is correct , but also shows the output voltage discharge AFT also accurate. The problem is why after switching channels down to 0.8V 4.4V from the moment the tuner AFT terminal voltage. Measuring IC102 ⑨, ⑩ pin voltage is 0.8V, and 11 feet for the 10V, visible , IC102 10,11 feet internal switch is not turned on. Then measured 12 feet voltage 5.6V, is a high potential, check the power supply voltage of 12V terminal 14 feet is normal, therefore , to determine the internal circuit IC102 10,11,12 foot has been damaged . After using TC4066 replace IC102, troubleshooting.r2yservice manual download site

    After the repair test IC102 pin voltage is about ⑤, ⑥ foot 1V, ③, ④ pin 12V, 11 feet 5.7V, ⑨, ⑩ feet 5.7V, ⑧ pin 4.4V. Failure to resolve the original phenomenon follows : TV channels in an instant convert , IC1102 ⑧ feet high output , control IC102 ⑧, ⑨ foot internal switch is turned on, 10, 11 feet off the internal switch , LNB voltage taps by the end AFT R155 Center determined and found to be 4.4V. After watching turned into a normal state , IC1102 ⑧ pin goes low , the control IC102 ⑧, ⑨ foot inside the switch is off, but this time should have turned 10, 11 feet, due to the internal circuit is damaged and can not be reliably turn , IC101 ② feet AFT voltage and therefore can not reach the LNB AFT end . After discharge LNB voltage by 4.4V AFT terminal on the external capacitor C111 down to 0.8V, resulting in an offset frequency tuner actually received , formed at the beginning of this article malfunction. IC101 ② feet under the action of internal AFT circuit output voltage will increase in an attempt to correct this frequency shift , but to no avail , so when a failure occurs IC102 11 feet higher than normal voltage .r2yservice manual download site

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