Hi All, maybe someone can help me to bring my TU81 back to life again. I have checked the following, before turning on: - All capacitors on the Mail Power Supply and the one below the vacuum pump are fine - Voltages check - Fuses Problem is, that the "Logic Off" is constantly illuminated, after turning on. I had a look into the Tx81 Pathfinder documentation, and checked the following. - Check if Blower is running - Disconnecting all DC connectors Pathfinder tells me changing the power supply. I hear only an relay clicking when turning on the Power Supply, also, when nothing is connected, in this time the "Logic Off" light blinks one time. I think, that the power supply checks itself that the voltages are OK, and that this fails. Any hints or tips? Many Greetings Ulrich