JVC "lt-42c550" LCD TV: on, but no backlight

[eti]

Hello.

I thought I'd ask here, where actual expert engineers gather, rather than speculating with amateurs on YouTube comments.

I have been given a JVC "lt-42c550" - my friend said it was taking longer and longer to come on, but would come on eventually, after about 10-15 seconds (immediately I now think "bad caps" based on what's coming up next...)

So now he brought it over and it comes on - you can see the LCD when lit with a flashlight, but the backlight isn't working. I found one YouTube video where a bloke replaced two caps and fixed his (similar model) TV.

Any "JVC" experts? I'll bet it's not even made by JVC! I'm used to servicing CRT TVs and VCRs, and stopped doing that in the 90s.

Thanks chaps.

[Brumby]

I will say at the outset that I'm no expert here - and haven't performed any such repairs - but from my observations of similar failure and repair reports, I can support your observation that bad caps seem to be very well represented as a common fault.

.... and, yes, it seems full in-house manufacturing is not seen much these days.

[eti]

Removed PSU board, will check for faults and bad caps later today

[DavidAlfa]

Leds burning down are very common in older TVs as they age.
In fact, I usually found more damaged LEDs, but "luckly" they were shorted, so the backlight still worked, until one of them failed open.
If it's for yourself and you don't want to spend money in new leds strips, a cheap fix is to short the open leds with a wire.
The LED circuitry works at constant current, it will work fine, won't overload anything.
Unless there're contiguous damaged leds, the light difference isn't very noticeable.
Otherwise replace ALL the leds, or you'll have to fix them every 3-6 months. They all have the same running hours, so it's likely for others start failing.

[GlennSprigg]

Sorry if I'm "barking up the wrong tree" hahaha...
Of the numerous Laptops I've worked-on/repaired, the problem with them is virtually always the BackLight Controller Board itself,
behind the bottom of the screen outer escutcheon. Easy access, and very cheap to fix/replace!  However, I realize that what you
have is a TV.  I found ONE video though, that explains how just one of the backlight LED's can take it down, and how he tests all
the individual LEDS's, to find the faulty one. Interestingly, he uses his Multimeter on 'Diode' test setting, as the power supply! which
lights up the LED's too, due to the extra voltage to overcome forward-biasing, and won't be affected/bothered by shorts.