How one electrical passive element can cause issue

26 Mar 2017

Few days ago I got TV with following issue: there is no way to power on TV (only standby LED is on). I have checked that all voltages on IP board (power supply and inverter) were correct. Next I have checked key elements on main board. After analyze of schematic I have found guilty: it was electrical capacitor 100 uF / 16V (C5068) located near 1.2 V LDO (placed under metal shield near the MCU). After replace of this element TV works properly.

Top Comments

kk99 over 7 years ago in reply to COMPACT

Yes, capacitor was short circuited.
- Cancel
- Vote Up +1 Vote Down
- Sign in to reply
- More
- Cancel
COMPACT over 7 years ago in reply to mcb1

There's now even lifetime calculators available.

NICHICON CORPORATION | Product & Technology
- Cancel
- Vote Up +2 Vote Down
- Sign in to reply
- More
- Cancel
mcb1 over 7 years ago in reply to COMPACT

Yes.
It resulted in many motherboards dying prematurely, but they could be fixed if the leakage haven't caused too much damage.
- Cancel
- Vote Up 0 Vote Down
- Sign in to reply
- More
- Cancel
COMPACT over 7 years ago in reply to mcb1

And cheap and nasty electrolytes!
Do you remember the Capacitor Plague at the turn of the Century?
- Cancel
- Vote Up 0 Vote Down
- Sign in to reply
- More
- Cancel
mcb1 over 7 years ago

Well done.
You'll be surprised how many LCD monitors suffer from faulty capacitors that prevent them from working correctly after a few years.
As manufacturers have tended towards switch mode supplies, the need for low ESR caps has grown.

Manufacturers have to balance costs with life, and sadly some big name companies are using 2000hr capacitors.
They get away with it on the basis that, that is the life expectancy when running at their rated temperature, and the cost of longer life versions climbs very steeply.

With warranty periods of one or maybe two years, it's becoming normal and something you'd expect from no name low cost brands.

Mark
- Cancel
- Vote Up +2 Vote Down
- Sign in to reply
- More
- Cancel