|
It would be unusual for the BF just to stop working...
The only thing that comes to mind is that the tuning position has been lost.
You could try holding the filter assembly onto the black box, not screwing it into place; low power eyepiece and just slightly tilt the assembly..the CWL varies slightly with tilt....worth trying.
(If I had access to a spectroscope I could quickly advise the possible problem)
|