The article presents the results of scientific - research to assess the reproducibility of the measurement results during the diagnosis of on-load tap changers (OLTC) by acoustic emission (AE). The study was conducted in a laboratory studying the effects of wear pin head OLTC working on the recorded AE signals. Assessment of the repeatability of the measurement results performed on the basis of the characteristic time. (Estimate of the repeatability measurement results obtained by acoustic emission method in the diagnosis of on-load tap changers).