The Illinois Tool 1605A is a circular chart recorder used for continuous data logging in industrial process control, typically measuring temperature or pressure with a probe and recording on paper or digital output. Common failure points for this class of equipment include worn probe contacts, degraded magnetic tape or print head, power supply voltage drop, and PCB component fatigue such as electrolytic capacitors or solder joint cracks. First‑check diagnostics: verify the unit’s input voltage and ensure it is within spec; inspect the probe connection and clean any corrosion on contact pins; examine the internal board for obvious signs of damage or burnt components before proceeding to detailed calibration or replacement of worn parts.[oss-gpt-20b]