SER FAQ: TVFAQ: Arcing due to bad connections to or disconnected CRT return

S.E.R. FAQ

NotTaR of Television Sets : Arcing due to bad connections to or disc..
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Arcing due to bad connections to or disconnected CRT return

The Aquadag coating on the outside of the CRT is the negative plate of the HV filter capacitor. If this is not solidly connected to the HV return, you will have your 25 kV+ trying to go where it should not be. There should be a wire solidly attached to the CRT neck board or chassis. Without this, voltage will build up until it is able to take some other path - possibly resulting in damage to sensitive solid state components in the process. Therefore, is is important to rectify the situation.

Warning: If you find this disconnected, don't just attach it anywhere. You may instantly kill ICs or other solid state components. It must be connected to the proper return point on the CRT neck board or chassis.