Pro150HD. Marginal Comcast cable signal despite several visits, but that's another story. They've just added some new HD channels, and some of them have poor S/N and have tons of macro blocking errors.
One channel in particular makes my monitor crash any time I linger on it for > 1 second or so. Let me repeat that: I can crash my set on demand any time I want just by visiting this particular channel.
When it happens, the screen is crawling with horizontal streaks of blocks and errors, then locks up, then powers off, then when I power back on (to same channel) it locks up again. Sometimes the only way I can get control back is to disconnect the cable input, then power up, then manually disable this problem channel.
I am a CS/EE, I write software for a living, and design microprocessors for fun. Having read this thread, I speculate this monitor has a control processor that interfaces to the remote, steers A/V source multiplexers, etc, and has a separate digital video processor that does digital and HD demodulation, decompression, etc. I speculate that if you feed a sufficiently marginal signal through ANT, something in this digital video processing pipeline will crash. Eventually the control processor notices the digital video processor/processing is not responding and powers down the set, flashing the blue lights as a diagnostic.
If that's what's going on, no amount of swapping boards like-for-like will help. And it is entirely possible the problem won't reproduce in the service dept. if they don't have your particular marginal signal source. You would need them to fix it / reproduce the problem in situ.
Of course no marginal signal input should ever cause a monitor to crash and shut off. The hypothetical digital video processor should shrug off such errors and (at worst) display some transient picture error for a frame or so.
If this is indeed what is going wrong, it may be possible to fix it through hypothetical firmware updates that correct hypothetical firmware shortcomings (out of bounds errors?) that allow the hypothetical digital video processor to crash on bad input. Or if it is a hardware problem, particularly on some VLSI IC, there may be no practical fix other than to avoid feeding it marginal signals.
If a Pioneer monitor engineer should wish to visit my home and see me crash my set on demand, please PM me.