[R-390] 16 KHz filter oscillates

[Flowertime01 at wmconnect.com]

Fellows,

I have a R390/A on the bench. As I peak up the 16 KHz mechanical filter it 
goes into oscillation. I get a nice audio tone out of the headphones. I can 
change that tone with adjustment and drive it beyond the audio range. The 
oscillation continues as it can be metered on the diode load. I can peak the 
level with the trimmer caps. I can back the trimmers back off the oscillation 
point and get a signal through the filter at almost the same level as the 
other filters. I do not know if the filter will ring at these trimmer 
settings with real world signals.

Is there a cure other than replacement? Will replacement cure the problem? 

The deck is late production but still with the black beauties. The only 
change was to get the orange drop in before power was ever applied.

Is there a wire dress layout problem that leads to this problem?

Thanks

Roger AI4NI</HTML>