466 Interface Bd 15V-65V short


Troubleshooting an issue with my 466, where both traces would get blurry (unfocus) intermittently. The problem appeared to be mechanical in nature, as it responded to taps on the case.
Opened it up and found a chalky, powdery bridge between C1737 (65V) and the 15V test point on the interface board. Cleaned it up, and appears to have cleared the problem. Has anyone seen this before?