We have a 20 amp 240 volt (split phase) Hotpoint Window A/C installed on our farm. The manufacturing date is 1979, but I have no other information on it. Recently when I turned it on, the fan started fine, but the compressor failed to start and was making a grinding noise, causing the power to surge. The breaker then tripped. I know about electrical and motors but know little about air conditioners. The unit only gets used a few times a year. What should I do?