I have a Spectra IV 23X with day/night capability, and lately I've noticed that when the camera has been still for a while, it drifts out of focus. Not terribly, but enough to definitely be noticed. Sending it to a preset seems to remedy the issue, but I would like to diagnose this issue and fix it. Any input is greatly appreciated.

Is there a bright and/or pulsing light source in the image frame? If so, that appears to be a problem with Spectra domes (and I believe many other brands because most dome PTZ's use the same Hitachi or Sony camera heads). Their autofocus circuitry appears to get confused and is unable to maintain proper focus.

The Spectra II BCBW was the first dome we had that experienced this. We had many talks with Pelco Tech Support and Manufacturing and they admitted that the Sony camera heads they used had "a problem with the fuzzy logic autofocus circuit". According to Pelco, Sony knew about the problem but refused to do anything about it. The biggest problem with the Sony cameras is that once they went out of focus, nothing could get it to come back, whereas the Hitachi replacement camera heads will usually refocus when moved.

Because of that, we have replaced the camera heads in many of our Spectra II and a few Spectra III dome drives. We do that in-house and have saved a huge amount of money by doing our own repairs. We purchase the parts from Time Lapse Supply. We figure we've saved over $80k in the last two years versus buying new dome drives for out-of-warranty PTZ's. That includes repairing just about any failure: camera heads, power supplies, logic boards, belts, fans, plastic parts and slip rings.