Open commissioning test, found the power supply work is normal, the filament light; Try to raise accelerating voltage. Found back to scavenging the shimmering green grating. That is a black screen. This machine circuit structure and M17 movement similar, plate is more, the circuit is relatively complex, because there was no circuit diagram, after repeated examination and control the actual circuit, found that putting plate, AV conversion circuit, three primary signal amplifying circuit and M17 movement similar, and small signal processing is given priority to with TA1215. And M17 small machine core signal processing with TA8880. Close scrutiny, found that TA1215 pin function and peripheral circuit and TA8880 basic similar, therefore TA8880 for reference.
 
 
In the state of the AV input VIDEO signal with oscilloscope detect TA1215 Y signal input (60) foot, have normal signal waveform, detection (16) and (17), (18) feet without R, G, B signal output. (19), (36), (50), (59) feet 9 v power supply are normal; Test the bus voltage, found that (13) feet SDA dc voltage is less than 3 v and fluctuation; (14) foot SCL end about 4 v, are not normal. CPU (30), (31) feet SDA and SCL (M17 movement (28), (29) foot SDA1, SCL1 respectively) and storage (5), (6) feet data bus voltage of about 5 v, normal. After shutdown, memory (5), (6) feet with TA1215 (13), (14) between the foot show high value or open circuit state (normal, (13) and (5) the feet and (14), (6) the feet q value are based on about 200 Ω). To find out the reason, from memory (5) and (6) feet. Along the SDA and SCL bus two printed circuit sections carefully check, check it has been three primary signal amplification IC602TA8889P (10), (9), found that memory (5) feet to TA8889P (10) feet between the SDA signal (in A27 (8) near the foot of turning point) printed circuit breaking point; Memory (6) feet to TA8889P (9) between the feet are high value, to show that the SCL clock bus TA8889 near the point of failure, check in A11 (1) between the feet and R638 via approximation. Will be more than two respectively with wire connection to the nearest well after the commissioning, troubleshooting.