| | Re: Help! Sudden Melting/burning Endcaps
This is what a poster in the other planted tank forum suggested just now:
"It's not a ballast/bulb combo problem and cooling fans won't stop it. The problem is the contacts in the endcap are loose. This causes a bad electrical connection, which makes for a high resistance and it sometimes arcs and always gets hot. You may be able to "squeeze" the female connectors in the endcaps a little with pliers to tighten them up. It's a common problem on molded endcaps for a lot of types of lighting."
Either it's a loose connection and/or corrosion in the end caps. Both explanations are highly likely.