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| # If solutions (1), (2) and (3) don't work, replace the U1 IC chip (74LS38). | | # If solutions (1), (2) and (3) don't work, replace the U1 IC chip (74LS38). |
| # If none of the above doesnt't work, replace the transistor Q1 (2N3904, NPN transistor) on the video board. | | # If none of the above doesnt't work, replace the transistor Q1 (2N3904, NPN transistor) on the video board. |
| + | |
| + | ===A Bright Pixel at the Center of the Black Monitor=== |
| + | ====Symptoms==== |
| + | When you turn on the The SE/30, you can see only a bright pixel at the center of the black monitor. |
| + | This phenomenon appeared after disassembling and reassembling the SE/30. |
| + | |
| + | ====Diagnosis==== |
| + | Both horizontal and vertical sweep circuits on the analog board don't work. |
| + | Although both circuits may be broken simultaneously, this possibility is very small. |
| + | This occurs most frequently when you disassemble and reassemble the SE/30. The most probable cause is that the yoke cable does not connect tightly to the P1 connector on the analog board. |
| + | |
| + | ====Solutions==== |
| + | Disassemble the SE/30 again, and check the connection between the yoke cable/connector and the P1 connector. |
| + | |
| + | ===Wavy Display, Swaying Back and Forth of the Image=== |
| + | ====Symptoms==== |
| + | Normal startup and normal display. But for a short period, the display is sometimes wavy, and the image is swaying back and forth (or small and large) on the display. Then, the display becomes normal. |
| + | |
| + | ====Diagnosis==== |
| + | The power supply is getting degraded and unstable with ageing. All components of the SE/30 can be affected by instability of the power supply. The monitor is most vulnerable, because it requires very high voltage. This symptom, in general, indicates fluctuation of voltage for the monitor. |
| + | |
| + | ====Solutions==== |
| + | Replace the power supply. |
| + | The power supply of the SE/30 (and SE) was made by SONY and ASTEC. The SONY power supply has less trouble than the ASTEC. |
| | | |
| =Notes= | | =Notes= |