If your Intellivision is having issues, check the below general troubleshooting information for help.
NOTE: If the RF modulator has been removed, the pull up resistor for the COLOR IC open collector outputs is no longer present. Attempting to measure these voltages will yield very low amplitude. Connect a resistor (3-10K) from the RF modulator video input point to 5V to be able to measure.
Black / Gray Screen
- Reflow cartridge port connections.
- Ensure all voltages reach the main logic board (check ribbon cable connection, not just the power supply board).
- For model 1, replace the two 3906 transistors near the CPU that often burn out.
- Check Master Clock Signal: Use a frequency counter to verify the master clock signal at Pin 10 of the cartridge port. Faulty crystals or capacitors (like C2) can cause failure.
- Swap out the Standard Television Interface Chip (STIC). It's interchangeable between models 1 and 2 (except for the model 1 heatsink, which may obstruct case closure).
- Swap out the CPU IC if necessary, though it is rarely the cause.
Graphics Corruption
- Reflow cartridge port connections.
- Replace Hi and Lo graphics RAM (ICs like 3539 or 2114). Bad RAM can cause graphical corruption or similar screen issues.