Slight popping noise coming from the flyback cap?

Stuffmonger

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I just changed out the monitor in my centipede with a WG 7302 monitor. I've used these monitors in 2 other games, and am happy with them. But, this one has a fairly quiet cracking noise coming from the flyback cap. Is there a bad connection on it, or is it certain that I need to replace the flyback? These monitors aren't that old (~1997 with limited use), so that's why I am skeptical as to if the flyback is bad.


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The original flybacks on many of this generation WG chassis are prone to failure. THe most common failure I have seen is cracking of the case resulting in arcing to nearby components and this usually sounds like a cracking noise.

Try turning out the lights and watching the monitor chassis for arcing.
 
I've seen this several times where it was just a dirty picture tube. Discharge and disconnect the HV lead. Clean the inside of the suction cup, and around the anode connection with Windex on a paper towel. Make sure there isn't any dust or dirt under where the suction cup will go. Allow it to dry, and reconnect the HV lead and push down the suction cup.

What happens is that carbony dust builds up and provides a path for the HV to arc.

If that doesn't fix it, or it's arcing near the flyback itself, then yeah, you need a flyback.

-Ian
 
There is no arcing between the frame and the monitor (the last one had that issue, which was why I swapped it out). I'll try cleaning the anode cap and see if that helps. If definitely sounds like it's coming from the cap, and not from the chassis near the flyback.


Edit: Ok, I cleaned the anode cap, and that seemed to do the trick. It wasn't very dusty at all, but I guess it had dust in the wrong spot. Thanks for the help!
 
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There is no arcing between the frame and the monitor

There wouldn't be. If it's a dirty tube, it would be arcing from the anode connection to the aquadag coating on the outside of the tube. Notice that the whole back of the tube is coated in a black conductive coating - except for the area around the anode connection, which is uncoated. If this area gets too grimy, it becomes a conductive path for the HV. You may or may not be able to see it arcing.

-Ian
 
clean the tube area well where the cap goes. Clean the rubber anode cup too. If you see any cracks in the rubber, you will need to replace the rubber( aka replace the whole flyback)

if it looks ok, apply a LIGHT coating of silicone lubricating paste around the outer 1/2" of the cap, bieng careful not to get any on the anode itself or in the anode hole..

i prefer this stuff because i use it as lube and it also works great as heat sink paste too..
http://www.foxruntools.com/3msiliconepaste.aspx
( also works well on steel to bronze bushing areas in our games)

if ng replace the fly.
 
if it looks ok, apply a LIGHT coating of silicone lubricating paste around the outer 1/2" of the cap, bieng careful not to get any on the anode itself or in the anode hole..

Why would you put a lubricant on the anode cup? That's just going to attract dirt, which will eventually provide a conductive path. You really want it to be clean.

-Ian
 
Why would you put a lubricant on the anode cup? That's just going to attract dirt, which will eventually provide a conductive path. You really want it to be clean.

-Ian

I have used silicon dielectric grease on many anode cups that wont stop arcing and it fixes them right up. Sometimes just cleaning the area and cup doesnt fix it. Alot of vectors had it on them from the factory.
 
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