Hello everyone,
I am repairing a screen, and the cause of the problem was a failed MOSFET - ME15N10-G, On the inverter board. This is probably the main driving transistor of the backlight, as it is the largest on the inverter board.

The MOSFET looked burned (not horribly, only the flux around it went brown) so I desoldered It and the short was gone from the PCB.

Now all I need is to find a replacement, I can order the same part for cheap on ebay, but I'm afraid it will burn again.

So I looked on digikey for a replacement with higher rating than the failed MOSFET and found the FDD390N15ALZ.

This MOSFET beats the failed ME15N10-G by all of the important voltage, current, resistance and power dissipation characteristics.

The only issue is the dynamic charge characteristic - the FDD390N15ALZ has some higher capacitance values.

My question is:
Provided that the driving frequency is lower than 300KHz, should I worry about frequency issues? i.e. the MOSFET will not change it's state the same way it has before.

I know that the rise/fall times are suitable for the frequency so I don't expect pulse skipping or change of the frequency due to the MOSFET not changing fast enough, but I don't know how the capacitance characteristic affect the exact on/off time, or if it even matters for the LCD backlight.

So should I order that FDD390N15ALZ?

Thanks,
128ITSH

 

First have you determined what caused the failure? Often times when I trace down a burnt component in TV the root cause is not always apparent from a burnt component but a symptom. There are cross reference resources that may help you match replacement better. I haven’t dug into this so do your research.

https://alltransistors.com/mosfet/transistor.php?transistor=31480

 

My question is:
Provided that the driving frequency is lower than 300KHz, should I worry about frequency issues? i.e. the MOSFET will not change it's state the same way it has before.

It looks like you already are worrying. That's a nice replacement but it does have a very substantially larger gate capacitance. It would make me nervous as well if I didn't know the frequency and how it's being driven, ie. whether the driver could handle the higher current. Lacking that information, I'd probably opt for the original part or one closer to it.

 

Or put 2 originals in parallel. Also Wolframore mentioned you need to find the reason for the burn, even if its a grid voltage peak.