VERY bad cap

[tattoodee]

Approaching my elderly mothers door recently I heard a crack which sounded like a .22lr rifle, on entering she informed me that it had come from the TV or the digital recorder box, she had immediately switched both off at the power outlet so I took a look, the TV was fine but when sniffed the recorder box smelt odd, but not exactly a "burnt electrical" smell, on opening it up I saw that one of the 220uf 16v caps had literally exploded off the board leaving both wires in place, before I attempt a repair does anyone have any idea what could have caused this?

[stj]

Re: VERY bad cap

clean up the mess and take another pic so we can see the area better.

[eccerr0r]

Re: VERY bad cap

Usually never see that kind of catastrophic failure with caps unless it was abused (like reverse polarity)... Weird...

[momaka]

Re: VERY bad cap

I guess the cap must have not had a safety vent. Because, even with reverse polarity and severe over-voltage, most caps with vents still just gas out politely.

[tattoodee]

Re: VERY bad cap

Well I replaced the cap and it didn't fix it, all I was getting was the front panel led flashing I'm guessing that either the exploding cap caused some other damage or some other fault caused the cap to fail

[momaka]

Re: VERY bad cap

We need more pictures. You may have other bad caps in the box or perhaps something else wrong with the power supply.

[stj]

Re: VERY bad cap

given the 4pin connector it's next to, i suspect it's related to the 5v or 12v rail
maybe the hardrive is not being powered, a lot of newer cheap-ass pvr's store the firmware on the drive and only have the bootloader in flash.

[tattoodee]

Re: VERY bad cap

I took a look at the rest of the caps and several of them are swollen , I imagine it has had it's time but it hasn't done too badly lasting 5 or 6 years of daily use.

[stj]

Re: VERY bad cap

so new caps then

[Behemot]

Re: VERY bad cap

I don't see the images but did the caps have proper vents? If they were ventless, its actually quite common for the pressure to leak through the bung.

[stj]

Re: VERY bad cap

vents?
he had the pair of plates and balls of brown paper syndrome!
no idea where the can went!!!