bigfred 

No "Guru" here, but will contribute my .02 all the same.

Agree with the others about identifying the root cause of both the "ping" and the loss of true before attempting to solve.

Is it in fact a "ping"? Or, more of a "click"?

Pings are most frequently spoke bind that issues that correct themselves in the first ride of a recently service wheel. But, potentially at the consequence of even tension, if that tension was achieved through spoke wind up.

Clicks can come from rim eyelets, nipples or the rim joint and can continue indefinately.

I don't disagree with the retruing/retensioning of the entire wheel. BUT, some thread locks/preps have a limited service life with regard to how many times they can be disturbed and still function. It might be necessary to actually unbuild the wheel and reprep the spokes. In which case it would be beneficial to know up front if you need to replace the rim or not.

If the click is rim joint related, it is not impossible to contiue to ride on that rim for some time without safety concerncs. But, I would find that difficult to do.

I would add more, but, have to go meet the other fat, old men for our Saturday Morning Mutual Distruction.