Author Topic: TV Repair - Choosing a MOSFET replacement - generic  (Read 530 times)

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Offline anonymic

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TV Repair - Choosing a MOSFET replacement - generic
« on: December 31, 2018, 09:19:40 pm »
I'm in the process of repairing a TV and believe the failure is down to one positively nuked MOSFET on the main board. It's an expensive board but I know the part number of the MOSFET. The problem is that it's only available in 3000 off quantity. I'm okay with replacing the part with an exact equivalent because apparently a firmware update to the board resolves the problem once it is repaired.

I've googled how to choose MOSFET's but I'm met with terminology and equations I just don't understand, use cases I can't identify, and in this application, a solution I don't understand. Searching here I mostly find users looking to solve specific problems for their circuit. Here the circuit exists but is merely missing a known component.

So my part number is ZXMP3F30FH P-Channel MOSFET in a SOT-23 package for what it's worth. One reference I found said it's okay to replace it with a BCW72LTIG or SBCW72LTIG bipolar transistor.  I'm not really interested in asking if that's appropriate because a yes or no really doesn't help me learn anything.  If anyone would like to expand on the whens and whys of replacing a MOSFET with a standard transistor, I'm certainly interested however.

My main question is, if I'm looking at a datasheet and I need something that isn't going to self destruct when I power the unit on, what parameters are most important to me to look for? Should I be looking for higher or lower values for those particular parameters?
« Last Edit: December 31, 2018, 09:25:44 pm by anonymic »
 

Offline Armadillo

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Re: TV Repair - Choosing a MOSFET replacement - generic
« Reply #1 on: December 31, 2018, 09:51:14 pm »
Replacement part recommended is TSM2307CX

Continuous breakdown Voltage and Currents, those listed as "Absolute Maximum Ratings" at the top of every datasheet.
You would have to read up about mosfet, I am afraid.

 

Offline anonymic

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Re: TV Repair - Choosing a MOSFET replacement - generic
« Reply #2 on: December 31, 2018, 10:18:38 pm »
Thanks for the part number.

My first go-around was with Digi-key's parameter search, which netted me the exact part and nothing else. Perhaps I should have selected a range from the datasheet value to something somewhat higher and that would have given me a range of solutions that would work. My concern was that if a particular parameter was too far from the datasheet value it would throw something else out of the acceptable range.
 


Offline anonymic

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Re: TV Repair - Choosing a MOSFET replacement - generic
« Reply #4 on: January 03, 2019, 02:46:29 am »
Thanks fzabkar, I've already ordered the part recommended by Armadillo.  TBH, the part wasn't the target, the reasoning was.
 


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