I doubt he replaced it. It depends on where the lights are used in service.. Sometimes lights can be used where bugs aren't frequent so they don't get in the fixture as much.
Or the fixture was sealed up nice when in service so no bugs got INSIDE.
But this is a clean fixture and looks similar to the inside of my OV-15.
My guess is CWA since it has a capacitor.... And no, not all older fixtures had caps. My OV-10 (although older than the 60's and 70's) has no cap, just a flat red ballast.
That's right the HX and reactor type ballasts typically did not have capacitors but some do, the caps are installed in parallel on the power supply lines. CWA, CWI, and regulated output ballasts always have capacitors.
Yeah HX and reactor ballasts without caps do last longer because when the cap fails it can overheat the primary coil. Caps are favorable though, for power factor correction to allow less strain on the electrical circuits.
Or the fixture was sealed up nice when in service so no bugs got INSIDE.
But this is a clean fixture and looks similar to the inside of my OV-15.
Did the ones without the capacitors (HX ballast) last longer than the ones with them (CWA ballast)?
The ballast in this is CWA right?
Yeah HX and reactor ballasts without caps do last longer because when the cap fails it can overheat the primary coil. Caps are favorable though, for power factor correction to allow less strain on the electrical circuits.