I have been using a Yaesu FT-897, ALS-600 with an MFJ 998 for years. I do this by using a DIN splitter from the 897's Linear/Tuner jack. One cable is the radio to tuner interface (din to phone type to the tuner so when I press tune, it tunes through). The other DIN also goes to the tuner as an amplifier interface. Today, I bought a Yaesu FT-847. I put the Y adapter on the Tuner DIN and it worked the same. I can tune the 998 with the radio's tune button, and the amplifier works. But.... My amp is turning off on me like a temp fault...it just clicks, the lights go off and the amp goes dead. I can reset it almost immediately by turning it off and on. It will work again just fine for a while and then do it again. I'm thinking this is an interface cable issue? I'm not sure. The interesting part of this is that I can run non-stop CW at 450 watts and no amp problem on the same frequency...just switch from ssb to cw. And another weird thing on ssb, is my amp meter says I'm putting out 500 watts, but my 998 tuner says I'm putting out like 19 watts. I tested this on the air and the ham who helped me said my signal went way down when my amp failed out. I turned the amp off and looked at the meters power reading while transmitting with no power, and my radio indicated 50 watts, the amp meter indicated 50 watts, but again, the 998 indicated like 7 watts. Perhaps the tuner is reading a good swr but having issues with the match, even though it's showing a 1.4 swr? Anyone have any clue as to what's happening? Should I interface this situation differently? I think MFJ sells the cable to go from the CAT to the tuner interface, but they also say the cable won't work for the 847, yet at the same time, will work for any Yaesu that works with the ATAS 100, which this rig does interface with. Any help with this would be much appreciated.