The P-700 phono board in model 22 Marantz units is prone to noisy output, mostly due to leaky transistors and diodes. I recently rebuilt a phono board on the Marantz 2230 receiver and decided to post a how to for anyone with soldering skills to attempt.
If your Marantz 22XX receiver is experiencing noise on the phono output or, you have soldering skills and want to go ahead and rebuild the board before it does, this post is for you.