I just shipped an Eimac 8877/3CX1500A7 date code 1981 from England to Northern Ireland. I used a genuine Eimac foam filled box. it arrived with an open circuit heater. Is this a common failure? Are the heaters in these tubes especially fragile or have I just been unlucky? 73, Alan G3XAQ -- Alan Ibbetson alan at g3xaq.net