Author Topic: [SOLVED] SOT23 351A3 markings cant identify  (Read 440 times)

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Offline Samogon

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[SOLVED] SOT23 351A3 markings cant identify
« on: March 03, 2018, 05:43:45 pm »
This is fluke 789 process meter failed to power on.
i have one good on the board. desoldered it and component tester said that it is mosfet n-ch with zenner between source and drain
i placed generic mosfet n-channel but without zenner and unit started working, but in off position it shows dashes, it mean not fully off, i suspect it is due to wrong transistor
« Last Edit: March 04, 2018, 03:12:24 am by Samogon »
 

Offline Samogon

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Re: SOT23 351A3 markings cant identify
« Reply #1 on: March 03, 2018, 11:32:56 pm »
Looks like i have found it
NDS351AN On semiconductors
http://www.onsemi.com/PowerSolutions/product.do?id=NDS351AN
 

Offline Armadillo

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Re: SOT23 351A3 markings cant identify
« Reply #2 on: March 04, 2018, 12:04:14 am »
Isn't that a typical bodily diode across drain and source. Where is the zener diode you are referring?
Will the dashes be the same in the off position?
 

Offline Samogon

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Re: SOT23 351A3 markings cant identify
« Reply #3 on: March 04, 2018, 12:10:24 am »
Dashes do appear at the off position
And maybe i was wrong about zenner, possible it was just diode.
I have already soldered it back and itnis under display with wierd snap-in system do not want to remove it. Who knows how much stress it can sustain.
Will order transistors on Monday, it is cheaper then fixing dosplay holder :)
 

Offline Samogon

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Re: SOT23 351A3 markings cant identify
« Reply #4 on: March 04, 2018, 03:11:58 am »
Correction:
Proper device found and it clearly states "Device marking 351A"
https://www.fairchildsemi.com/datasheets/ND/NDS351AN.pdf
 

Offline Samogon

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Re: [SOLVED] SOT23 351A3 markings cant identify
« Reply #5 on: March 10, 2018, 05:01:06 pm »
Installed transistor and dashes have disappeared when meter is off. That was simple repair.
 
 


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