Need Advice: SF 6P w/drop-in Problem

I have an early original SF 6P and recently after discovering this wonderful forum purchased a DX 3W Cree drop-in module, 3V-18V input (6090). The new drop-in is fantastic, but oftentimes after reassembly I have to tap the light for it to come on.

To somewhat complicate matters I think I destroyed my original tailcap while trying to fit Trustfire RCR123s (apparently too long), but gool ole SF was kind enough to replace the tailcap with a model Z59 at absolutely no cost. And now using AW's RCR123s, thanks CPF.

I did not use the outside spring shipped with the new drop-in as learned here and the fit seems fine, no rattle or gap. What did I do wrong?

Thanks in advance for your replies.

Easy answer would be to fault the DX module . But sounds like an issue involving the contacts. Clean them, extend necessary springs, try other cells.

Thanks adamlau.

I have used multiple sets of new batteries with the same result and have attempted to clean and lube the entire flashlight. It appears that the lamp and tailcap springs are functioning correctly? Is it possible that the new drop-in is not seated properly?

I guess my best question is what parts exactly need to be making good contact?

What I suspect is that the flashlight body isn't making contact with your lamp assembly - which is a common problem with older 6P's and generic drop ins.

You may need to put a spacer ring between the lens and the reflector.
Hence why when you tap the unit, it will turn on.

This is why with older 6P's, its probably best to go with a OEM P60L LED LAmp assembly. I did that with all of my old 6P/9P/9Z/3P's that are marked "Laser Products". This ensures I get a good fit. I lose a bit of lumen brightness, but it fits and it works every time.

-Steve