Hi Fluorfan96

With electronic ballasted CFLS that program preheat. Do their electronic ballasts 'lose' the ability over time subject to long term no usage, therefore becoming Instant Start type?

Because with one or more of my 2000s era CFLS, I remember them program preheat bak in the day as a child but recently running them up lets say 2014 or this year, they start up instantly with no preheat!!!!

Has someone experienced this?

All best

Programmed start electronic ballasts are rarely used in CFLs (Osram Dulux Facility and Megamen Ingenium uses it). Most CFLs with warm start electronic ballasts, uses PTC to delay the starting before the electrode heats up, so when hot restarting them, they starts instantly. If the lamp began starting instantly also during cold start, the PTC has failed.

The PTC in fact makers the ballast programmed start, of course only when it is working.
Some designs use a VDR (of a voltage higher than the lamp arc voltage) in series with the PTC, so once the lamp sucessfully starts, the voltage becomes lower than the VDR threshold, so the VDR blocks the current, so PTC is allowed to cool down, so become ready for the next ignition. Plus it is supposed to reduce the stress by not maintaining the PTC hot all the time the lamp is running. Or better say that is, how it is supposed to work.
In real life the VRD uses to have high enough capacitance to leak sufficient current to keep the PTC warm (the CFLs are apparently designed to operate on higher frequency and/or higher ambient temperature than the VDR/PTC combo was designed for), so nothing much changes for the operation compare to bare PTC.
Then because the PTC/VRD combo is designed but not allowed to cool down, it tends to fail pretty soon and usually the lamp becomes an effective rapid start (depends on the exact design, most designs have limited resonant current and voltage for ignition, so the arc ignites only after electrodes warm up to emission, even when that happens within fraction of a second).

The fully electronic programmed start control is indeed very rarely used in CFLs, mainly due to cost reasons. Simply said, even when aiming for longer life/higher swtching cycle life lamps, it is still a bit easier to use more robust cathode shape (those double spirals or so, which tend to direct the fast ions to collide into themselves instead of abrading the cathode) and use the rapid start design (limit the voltage during ignition). Of course, you can not get into 20khour range range with these, but 10..15khours (in the home cycle, so about 5k starts) is rather realistic, definitely to make the tube life not the weakest point in the system. For longer life there is a need for more expensive passive components of the ballast (the electrolytic whose tend to dry out, the starting resonance capacitor which tends to develop a short circuit because of the TDDB, the coil assembly where the glue holding the core together tends to fail; all has longer lasting parts, but these are bulkier, more difficult to make with more production/recycling environmental footprint and therefore more expensive)

Hiya dor123 and Medved thanks for your answers. Ah so basically most of my CFLS use a PTC/VRD setup in the electronic ballasts! Pity that the thermal issues cause it to fail. I knew I was not going mad when I noticed with my 2000s era CFLS doing a cold instant start instead of the 'warm' start feature that the PTC/VRD provides.

Recently I bought 2x MEGAMAN Compact Classic GLS CFLS and when I tested the one thad a slight rattling sound because I thought the tubing inside got damaged and after 2 seconds of no light, it came on as normal and was relieved. I don't think they are program preheat as they do not have the Ingenium logo on the boxes, so basic PTC/VRD setup in their electronic ballasts.

Anyhow this all solves my experience with the so called old school 2000s era CFLS I've been collecting were instant starting from cold