[SignalOne] CX-11A Issue

[Robert A Sullivan]

I’ve been working a CX-11A whose symptom was it would function perfectly for a few minutes (it would vary) then go ‘dead.’ After considerable troubleshooting the issue was isolated to the synthesizer board thanks to the extensive use of cold spray and a heat gun. It was impossible to identify the culprit although I could duplicate the symptom by using heat and cool in one area of the PCB. Replaced numerous components (including IC’s) to no avail.

Investigating the bottom of the board (with magnification) I saw tiny cracks on a couple of lands near one of the IC’s that ran quite hot (normal for the chip). Reflowing the solder in and around the IC solved the problem. (So far, so good). If the photo attaches you can see the long term of heat at one end of the board.

Put this in your “it might happen to me” drawer.

73, Bob
WØYVA
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