I decided to carry out the PA1O mod for 4 meters and also install the CT1FFU preamp board, The preamp board was a very easy install.
The PA1O mod was also pretty simple and very rewarding the power is up at 85 watts now from 15 or so, It did take a bit of rummaging through the radio to get to the board to carryout the modification, once you get to the board its a case of desoldering a capacitor and thats it.
well sort of if your 847 has some transistor for controlling the ALC level on 4 (as i understand) you'll need to cut a leg off from it, mine had this transistor.
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEheKWZKUtSzNx07iT-S6qFfxqpjpbIkzdSCynfuiFO5Cuw9HfGOuylXccWP5mSRzPHtlJPqi5q4bglwRcztqwB_ui33P-r7GOVKCJ1gO5cDR4ZuzIQT6FpwyuIuhBg69hZzPlSu3AOW92vm/s320/IMG00155-20100723-1007.jpg)
The HF and 4/6 meter final board at the top of the picture
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEguLOMJp2JmhWWr-LkoF2jitwH2JwKsHUMP5dxGLn8vXq1BrQ7qAwB2FVGcvHt77DifceXJGii1ViDHR6Gca3uIBS8YPUR2wgYs1TuRQNrhOzira6blshyt-EwVQe7muiRgaWPsjT2ITpAe/s320/IMG00154-20100723-1004.jpg)
Digging!!
During the installation of the CT1FFU preamp.
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjWcL_egS3rwG3dYkMo8diuOS2YrpIWqhXRcCJjrxesLWT8By5NjphL-Iz5yJx3QYAHosyoCj-d7FZvv6Ns-pBNR0ijExG6CG2NwMemmJ-JrL42QtTqPplwBgXcbB_rFL3fpmokjk6aCSNh/s320/IMG00152-20100723-0935.jpg)
The CT1FFU board installed, its in a far more accessible location than the Power modification, I opted to attach the red + to a track that was more accessable than the one suggested (its not attached in the photo yet).
GM0USI Alan who lives close by has a 847 with a different preamp board and a different power mod. the plan is to get the radios side by side at some point and compare.