Arrived on site to perform mini split diagnostic. Upon arrival client stated that head unit has no power. Began diagnostic at disconnect and found no power present, reset breaker and only 90 V was present. Continuously reset breaker and the same 90 V was being sent out. Due to the breaker being over 30 years old it is possible that it has weakened and is becoming defective which is resulting in the unit not getting 240 V. Advised client will have to double check availability of breaker at shop and will get back to him Monday. Upon departure unit is non-operational and client will you central heating furnace in garage for meanwhile.