How much bulge means a bad cap?

[Viper01]

How did you find PF?: Searching for how much bulge means a bad cap?

Hi!

I'm a new member.
My Xbox One and 50" Plasma got busted from a lightning even with a 2 surge protectors to protect it. Both would not turn on anymore.
Tv is rarely use and I still hoping I could fixed it before I bring it to the electronics depot. I opened it and hoping for a burned parts but did not see any except this capacitor. Have not tried to test the capacitor for I need to bring it to work so I can hv the proper equipment to test it.

Do you guys think this cap is bad already?

Thank you!

 

[berkeman]

Welcome to PF.

It does look to be bulging a little bit, but I doubt that would cause the whole TV to not work. More likely the input fuse was blown if there are MOVs inboard of the fuse (that's how surge protection works sometimes). Have you been able to find the input fuse and beep it?

If the input fuse is intact, it's likely that the surge caused a latchup somewhere, leading to the failure of a semiconductor. When you turn it on, does it draw any input current? Do you have a Kill-o-Watt or other power measuring device that you can use to see if it's trying to turn on?

BTW, you may already know this, but please don't be probing inside the TV when it is connected to the AC Mains. Disconnect from the AC Mains to test the fuse inside, etc. The only way you can probe inside a powered-up device like that is if you are using an Isolation Transformer and really know what you are doing. Thanks.

 

[DaveE]

Yes, I agree that cap probably isn't your only problem.

However, my rule is any bulge is too much. For most people it is just easier, and better to replace it that to worry about measuring it or guessing about it's current or future health. Electrical components shouldn't show any mechanical deformation, ever.

 

[Rive]

Regarding repairs, that cap is a goner regardless it's likely not the (main) reason for not powering up.
That is the way (of repairs).

But the problem with lightning strikes is, that without detailed and professional analysis you just won't know what's wrong. And this includes measurements on the primary side, in 'live' conditions. Unless you are qualified just don't do that.

Since it's already open, just check the fuse (with power cord disconnected), then close back everything and find somebody qualified.

 

[Viper01]

Welcome to PF.

It does look to be bulging a little bit, but I doubt that would cause the whole TV to not work. More likely the input fuse was blown if there are MOVs inboard of the fuse (that's how surge protection works sometimes). Have you been able to find the input fuse and beep it?

If the input fuse is intact, it's likely that the surge caused a latchup somewhere, leading to the failure of a semiconductor. When you turn it on, does it draw any input current? Do you have a Kill-o-Watt or other power measuring device that you can use to see if it's trying to turn on?

BTW, you may already know this, but please don't be probing inside the TV when it is connected to the AC Mains. Disconnect from the AC Mains to test the fuse inside, etc. The only way you can probe inside a powered-up device like that is if you are using an Isolation Transformer and really know what you are doing. Thanks.

Hi!

"When you turn it on, does it draw any input current? Do you have a Kill-o-Watt or other power measuring device that you can use to see if it's trying to turn on?"
- When I turn it on, I usually hear a sound every time I plug it in and the usual red light on the on/off sw.
Green light does not goes on anymore the next press on the switch or the remote to turn the tv on. There is a box where the plug goes in that I will open next time when I got the chance. Maybe there's the MOVs inside.

Appreciate all your response.

 

[Tom.G]

For what it is worth, I've repaired several computer monitors and laptop power supplies that died, by replacing ALL the electrolytic capacitors in the power supply. If one cap has failed you can be sure the rest have degraded.

The observed indication is usually one, or occasionally two, electrolytics have a domed top, indicating failure. The switching power supply simply stops switching.

There is a box where the plug goes in that I will open next time when I got the chance.

That sounds like it is the power supply, and the most likely failure point.

See if you can find someone competent to measure the power supply output voltage(s), (if any!).

Have fun,
Tom

 

[jsg2021]

How did you find PF?: Searching for how much bulge means a bad cap?

Hi!

I'm a new member.
My Xbox One and 50" Plasma got busted from a lightning even with a 2 surge protectors to protect it. Both would not turn on anymore.
Tv is rarely use and I still hoping I could fixed it before I bring it to the electronics depot. I opened it and hoping for a burned parts but did not see any except this capacitor. Have not tried to test the capacitor for I need to bring it to work so I can hv the proper equipment to test it.

Do you guys think this cap is bad already?

Thank you!

The "safe answer" is ANY bulge is a bad sign.

 

[phinds]

my rule is any bulge is too much

+1 on that