why do flyback transformers fail

while flyback transformers can on occasion be blown due to a failure elsewhere in tv or monitor power supplies or deflections circuits,in most cases,they simply expire on their own.why?

flybacks are wound with many layers of really really fine wire with really really thin insulation.the entire assembly is potted with an epoxy resin which is poured in and allowed to cure.

in some ways,these are shorts waiting to happen.

imperfections while mfg these transformer and operating temp are hot insulation and epoxy cracks allow moisture to seep in cracks shorting out windings.once the sparking and arching starts develops usally its terminal time to replace.also windings break down and short out.its amazing they last as long as they do eight to ten years under optimnal operating conditions with outpower surges or outages.so remember in electrical storms unplug your tv for safty reasons if nothing else.