I use to have a Pioneer Pro-77 RPTV. For the last few years (since about the time I started using my Pronto) I would once a week or so have a problem where the Pioneer TV would not turn on. Discrete On from the Pronto wouldn't work, power toggle on the original remote wouldn't work and even the power button on the front panel wouldn't work. To get the TV to work again you had to unplug it for a few seconds and then replug it in. I assumed there was some flakey relay in the power control some where. I never bothered to have it looked at.

Well I now have a two day old Pioneer Pro-530HDI, and the exact same thing just happened to it! So I don't think it is flaky hardware anymore. I think there is some remote sequence that is putting it in this mode.

I'm using the Pioneer TV discrete on/off codes from this site. The rest of the codes were learned from the original Pro-77 remote (and seem to work fine for the Pro-530HDI also).

I guess it could be an IR Sequence intended for some other device that is causing the problem. For the record the other components I have are:
Pioneer VSX-26TX Receiver
Pioneer DV-F07 DVD Jukebox
Philips DSR-6000 DirecTivo (Using code 1)
Philips DSR-6000 DirecTivo (Using code 2)
Panasonic PV-VS4820 VCR
Audiotron
Panasonic CP-72 DVD player

(But the Pioneer TV power on problem pre-dates the Audiotron and CP-72)

Anybody seen anything like this? Any clues on how to debug?

Here's an idea, Learn the codes from the new tv's remote. Do this directly on the pronto, with it disconnected from the pc.

The reason why I say this is because you might have a dirty code from the old tv set. Since you said that you are still using some of the old codes for your new tv.

Rob

Okay, I did relearn all of the codes from my new 530HDI remote. Only time will tell if this improved things. The old Pro-77 TV would only get messed up about once a week. The new 530HDI only got messed up once before I switched to using the new codes.