Problem

No video.

Diagnosis

Fresh from the memory of my recent Cruis’n World repair, the first thing I decided to check was the 7407 at U82. Indeed, the CSYNCX output was high. However, the inputs didn’t look too great either.  Tracing this CSYNCX signal back, I found that R437 had a resistance of 2MΩ instead of 33Ω. Replacing R437 got us this:

We appeared to be entirely missing the blue output and one or two bits of the red and green outputs. All resistors on the blue output tested open, as did R4 and G4 of the red and green outputs respectively. After replacing the resistors, the correct image was restored:

Note: For the replacement resistors I used 0805 SMD, 0.1% 1/8W.

Fix

Replace 7407 at U82.

Replace R437 (CSYNCX).

Replace R560, R561, R562, R563 and R564 (B[4:0]).

Replace R565 (G4).

Replace R504 (R4).

Philip Bennett