Pioneer DVL-909 Service Guide - Page 20

DV-505, DVL-909, DV-S9 3.8.3 Startup Sequence The basic flow is shown below. The parentheses indicate a limitation: "base" represents base models, such as the DV-505 and DV-S9, and "compatibles" represents DVD-LD compatible models, such as the DVL-909. (1) Closes the tray. (2) Runs the tilt servo for 1.5 seconds (compatibles). (3) Detects the peak. (4) Distinguishes the disc. (5) SGC (6) Turns on the focus servo. (7) Turns on the tilt servo (compatibles). (8) Starts the spindle rotation. (9) ATB (10) Measures the MIRR modulation degree. (11) Turns on the tracking servo. (12) Turns on the slider servo. (13) Turns on the spindle servo. (14) Focus AGC (15) Tracking AGC (16) AFB (17) Plays AGC (base for CDs) (18) Plays back. ∗ For a 2-layer DVD, steps (9) through (16) are repeated for each layer. ∗ When starting up with [TV/LDP] in Test mode, all the steps (1) to (18) are performed for a DVD, and steps (1) to (10) are performed for a CD. 3.8.4 Peak Detection Overview This is a new function to measure the size and location of the sine wave related to focus errors at the beginning. The measurement is performed in the normal startup process and in Test mode, as well. If the sine wave is small, the OE IC gain is switched. Only the judgment for NO DISC is accomplished at this time. The operation is in effect as for judgment for DISC . Using the Function in Test Mode This function is not assigned to any remote control keys. Only an open/close operation can trigger the function. 3.8.5 Disc Distinction Overview This function is almost the same as that with the first-generation models. The only difference is as follows: If an error occurs in the startup sequence and playback cannot be started, startup is retried after forcibly switching the disc distinction from DVD to CD or vice verse by a backup process. If startup fails again, it is canceled, and an error is generated. The types of error that triggers the backup process for disc distinction are discussed in the next section. Using the Function in Test Mode This function is not assigned to any remote control keys. Only an open/close operation can trigger the function. 3.8.6 SGC Overview This is a new function to maintain the sine wave related to focus errors to a certain size so that the sine wave shows 1.8 V for the Pto-P value. This operation is performed each time after judging disc presence and distinction in the normal startup process and in Test mode, as well. The operation is achieved by switching the FE gain inside the RF IC (LA9700) by using the voltage at the SGC connector (pin 22) of the RF IC. Using the Function in Test Mode This function is not assigned to any remote control keys. Only an open/close operation can trigger the function. 3.8.7 Measurement of MIRR Modulation Degree Overview The slice voltage of the RF signal is measured and used in the calculation to generate the MIRR signal. This operation is made in synchronization with ATB ON/OFF in normal startup and in Test mode, as well. 3.8.8 AFB (Auto Focus Bias) Function Overview Among the first-generation models, this function supports only CDs with the basic models, such as the DV-7. Among the new models, this function supports DVDs with all models, but CDs only with the basic models. The operation is executed only once (once for each layer for a 2-layer DVD) after the focus and tracking AGC at startup. The operation is accomplished not by centering the focus servo to Vref (2.5 V), but by gradually changing the center value for the optimum jitter value. Thus, performance with an improper or dirty disc (by fingerprints, etc.), or the temperature characteristics (at 0°C, 35°C, etc.) will be improved. OverviewUsing the Function in Test mode (the Remote Control Keys to be Used are Indicated in Brackets) As the function is to be synchronized with AGC, turn on and off AFB by pressing [TEST] + [7]. The jitter value measurement cannot be made with AFB ON. 20