Electronics issue

[333rocky333]

Called out to an horrendous burning smell, but was unable to pinpoint, so had to return, finally traced it to this cctv monitor, however on initial visit, despite the obnoxious smell making there staff ill the monitor was still working..
Though on return visit it was now off, opened it up and found this.
Any ideas what may have happened, something appears completely gone,, possibly some sort of fusing component maybe?.
Just an Earth connection to the casing maybe?

Screenshot_2022-02-26-18-15-41

• 333rocky333
• 26 Feb 2022

Screenshot_2022-02-26-18-15-12

• 333rocky333
• 26 Feb 2022

Screenshot_2022-02-26-18-15-22

• 333rocky333
• 26 Feb 2022

Screenshot_2022-02-26-18-15-48

• 333rocky333
• 26 Feb 2022

Screenshot_2022-02-26-18-16-04

• 333rocky333
• 26 Feb 2022

 

[Deryck Tintagel]

Is that a loop of wire in the third image?

 

[333rocky333]

Is that a loop of wire in the third image?

Is that a loop of wire in the third image?

Prodding it it felt like a couple of wire legs, going by all the writing on the pcb i googled fp8115 and found this, so i wonder if similar was there.

 

[RandomGrinch]

After some confusion, the model number of the PCB is PWI 1702 SM
Here is an intact PCB!
https://www.aliexpress.com/item/32837953375.html
The burnt out connector is to one of the High voltage CCFL tubes (it's not a modern LED monitor!).
So it could run at about 600V RMS (edit: or more!), but at a very low current.
A dodgy connection, a short, a bit of arcing and that could be the result!
And as it's only one of the back lights, the monitor would probably carry on working without anyone noticing!

But that's just my theory!

Edit:
After some further research, it looks like the transformers for the tubes are usually constant current, if there was a break in the circuit/broken tube etc. the voltage could climb rapidly - if the protection doesn't kick in, an arc could form at the point of least resistance!
Example here:
https://www.badcaps.net/forum/showthread.php?t=15464