PTC replacement in 28w T5 ballast - value?

[cape zoloh]

The PTC blew in a 28w T5 ballast and I need to replace it.
Problem is, there is no component left to measure, as it exploded.
Anyone with knowledge of what type of PTC I need to get?
The ohmage of these varies quite a lot.
I understand that a sufficient voltage rating is needed, but the rest is unknown to me.

[Kleinstein]

A first question is if one really needs the ballast or would change to LED light in short time anyway.

A PTC may make sense as a kind of fuse - if blown, chances are that there are more problems. For a replacement one would look for a suitable PTC fuse for the expected current.
However the part may also be a NTC for inrush current limiting. Ideally the NTC you can buy have a datasheet to tell the right one for the size of filter capacitor and expected inrush current.
Similar to the PTC case there is a chance that there are more defects. So a replacement NTC/PTC may well blow again in relatively short time.

[cape zoloh]

I'm well aware changing a fuse might change nothing, but as this lighting fixture have worked for years I'm willing to try, but getting a correct PTC seems very hard without more knowledge. A 28W T5 tube is a known current. Maybe I'll try one of those Vishay PTCL I think the series is called.
Might be right regarding LEDs. However this is my parents designer lightfixture, and they will never let it go...maybe I can modify it...