Johnson Fitness EP250B is the main motor‑control and speed‑regulation board used on several mid‑range treadmills. Common failure modes for this unit include burned or swollen electrolytic capacitors on the power input section, damaged MOSFET driver ICs that control the traction motor, and shorted voltage regulator modules that supply the logic circuitry. The board also tends to exhibit intermittent operation when the motor current spikes exceed its rated limit, often indicated by a “motor overload” fault code in the treadmill’s diagnostic display.

First‑check diagnostics: verify the 24 V DC power supply output and look for any visible signs of component damage (burn marks, bulging caps); test the logic voltage rails against the board’s reference levels; and review the treadmill’s error log for motor‑overload or driver‑fault codes before proceeding to component replacement.[oss-gpt-20b]