Sounds like a protection relay. It may be that a device overheated and failed- thus the protection relay kicked in to prevent the amp from destroying the speaker.
Either way it sounds like service is indicated. I would weigh the cost of repair against how the amplifier served your needs; if a replacement amp is costing over just a few hundred dollars then its likely the amp is very well worth repair, assuming service info is available.
Either way it sounds like service is indicated. I would weigh the cost of repair against how the amplifier served your needs; if a replacement amp is costing over just a few hundred dollars then its likely the amp is very well worth repair, assuming service info is available.