Why Are Some Circuit Board Components Glued?

[spongella]

While in the process of restoring a Realistic DX-302 a few dozen caps were replaced. Some were glued to the board at their base while some were glued to an adjacent component. In the photo attached the large capacitor on the Counter Board was anchored onto the IC below it with glue. You can see a bit of the adhesive on the top. The glue was very tenacious and was slowly cut away with a razor.

Does anyone know why certain components are anchored with adhesive? This was a new one for me. Thanks very much.

 

[prcguy]

Its either to keep larger components from moving ripping off the board during rough handling or some components are sensitive to vibration (microphonic) and can induce noise into circuits when vibrated. Coils used in PLL circuits are often blued and potted with wax for this.

 

[spongella]

Its either to keep larger components from moving ripping off the board during rough handling or some components are sensitive to vibration (microphonic) and can induce noise into circuits when vibrated. Coils used in PLL circuits are often blued and potted with wax for this.

Prcguy, that makes a lot of sense, thanks. Okay on the coil wax, been there, done that when realigning. Untouched coil wax is a giveaway that no one's fooled with them since leaving the factory.