Black Box IC515C Service Manual download pdf (Page 118)

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28. Auto Registration Troubleshooting

FIGURE 28-1 - SENSOR LOCATION AND NUMBER

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Fortunately, the RA-5A and RA-6 chassis have included a new set of instructions known as “COPY” and “ALCOPY”.

Convergence is adjusted in the FULL mode, saved and Flash Focus

offset rewritten. ALCOPY is selected from

the PJE menu and the data changed from 0 to 1. Pressing “Mute” – “Enter” copies the data from the FULL mode

to all the others. The COPY command will perform the same function but will not copy the data to the WIDE

ZOOM mode.

TIP: Pressing the “DISPLAY” button on the remote while in the PJE mode will immediately engage the “ALCOPY”

feature without having to scroll all the way back to the beginning of the PJE menu.

Flash Focus

Errors

It is quite frustrating to receive an error message while attempting to write sensor offset data after a lengthy

convergence session. In some cases, errors occur after minor touchups in the fine mode. In order to obtain a

better grasp on dealing with this situation, it is necessary to have a basic understanding of how this circuit

functions. Figure 28-1 illustrates the screen and the sensor locations.

Although earlier designs incorporated eight sensors, the four-sensor arrangement is more common, used in all

of the newer sets and will be used for illustration purposes.

Sensors 0 and 3 are used for horizontal centering, skew and limited vertical size control. Sensors 1 and 2 are

used for vertical centering, skew and limited horizontal size control. It is important to know the numbers of these

locations since they are identified when an error occurs during Flash Focusing. If the model uses eight sensors,

the adjustment section of the service manual will illustrate the sensors and their identification numbers.

The convergence CPU generates the red, green and blue boxes that you observe “dancing” at the edge of the

screen during Flash Focus

. They are technically known as “flags”.

Figure 28-2 demonstrates a somewhat exaggerated view of the green flags displayed while Flash Focusing.

The sensors are shown in their normal location outside the screen bezel. The flags do not appear simultaneously

as shown. They “dance” from side to side and top to bottom. The pair starts near the left side of the sensors and

moves to the right to establish an offset voltage based on the light received by the sensors for each pair of flags.

When Flash Focusing in the service mode, the offset voltage is read and compared to the adjustment data you

have written in memory. This will establish the necessary offset data to be written so when the customer uses the

Flash Focus

, the sensors will know where to position each color to the previous service alignment. In the

customer mode, they will stop when the correct offset is matched to that in memory.

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Black Box IC515C Service Manual Page 118