[TenTec] Model 289 Noise Blanker - Question

[Dave Burnett]

I have a Model 289 noise blanker in my 580 Delta, but it doesn't seem to work as effectively as I would expect, especially in the presence of local power line noise.  I don't have a lot of experience with it, so is there anyone in the group that can tell me how well it should be expected to work?  Any experience troubleshooting them?

73,

 -Dave
WD8KRV