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Check that the decode board U2 (CL680) and its 67 foot hot anomaly, composite video signal output end voltage is 0V. Measurement of U2 3.3V basic normal, but two buck diode power on the heat is amazing. U2 part of the judgment of damage (otherwise the operation, VFD display, etc. can not be normal), then decided to replace U2.pZqservice manual download site
After the change of U2, also check out the impedance matching resistor R12 (75) (67) has been open circuit, it is replaced after the boot, and found that the situation is not as U2. But at this time U2's heat has become normal, 67 foot voltage is also basically normal. Like CL680 fine integrated block end feet, and some pin because next to the parts block, welding is not very good operation, so do not rule out some pins are not being welded. So the decoding board removed, the CL680 and a careful re - welding, confirmed that no error on the machine, after starting the image out, but still no sound.
The audio signal of the machine is sent to the rear of the AV output board after it is sent to the Cara OK board. 7805 input only a few tenths of a volt voltage on the check plate, AIC3 (4558D) in the foot working voltage is only a few tenths of a volt. Hand touch panel parts, found AIC3 hair perm, apparently it has been damaged, will be replaced after the sound normal.
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