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Old 05-20-2011, 09:53 AM   #1
newbie1
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Default Need help identifying faulty transistor & replacement

Hey guys,

Its me again.

Model : Dell 2407wfp

Failure : No power LED. Owner claimed that upon switching ON the Power switch a Pop sound was heard + burning smell coming out of monitor.

Dissambled it and I can see that one of the leg of the Big cap is almost/already broken. 2 pink resistors got burnt. Proceed to measure some of the components & found out that
1) Main Fuse open
2) Bridge rectifier shorted
3) Transistor Q601 shorted
3) Transistor Q651 shorted

So now i am needing the experts here to identify what is Q651. Marking on it is K3502 P65775(Fuji?). Also are there any other replacement option parts for the Bridge rectifier (Marking GSIB4A60) & Transistor Q601 (Marking 2SK3548)?
For Transistor Q601 (Marking 2SK3548) I could only find 2SK3549 but I am not sure whether it is compatible.

Thanks in advance, Guys!
Attached Images
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File Type: jpg DSCF2994.jpg (310.7 KB, 70 views)
File Type: jpg DSCF2995.jpg (243.5 KB, 59 views)
Attached Files
File Type: pdf Fuji-Semiconductor_Actives-and-Passives_9250017[1].pdf (125.9 KB, 45 views)
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Old 05-20-2011, 09:59 AM   #2
Rtech
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Default Re: Need help identifying faulty transistor & replacement

The bridge is easy,data sheet attached ,lots of similar ones about from many different manufacturers.Ensure the pin spacing is correct as shown before ordering.

http://pdf1.alldatasheet.com/datashe.../GSIB4A60.html
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Old 05-20-2011, 10:02 AM   #3
Rtech
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Default Re: Need help identifying faulty transistor & replacement

The K3502 is probably this :-

http://pdf1.alldatasheet.com/datashe...I/2SK3502.html
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Old 05-20-2011, 10:15 AM   #4
newbie1
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Default Re: Need help identifying faulty transistor & replacement

Quote:
Originally Posted by Rtech View Post
The bridge is easy,data sheet attached ,lots of similar ones about from many different manufacturers.Ensure the pin spacing is correct as shown before ordering.

http://pdf1.alldatasheet.com/datashe.../GSIB4A60.html
Quote:
Originally Posted by Rtech View Post
Thanks Rtech. Appreciate your lightning quick respond.
I will check for the identical replacement parts. Just incase I couldn't find them, are there any other alternative replacement that you know of to replace them?
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Old 05-20-2011, 10:57 AM   #5
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Default Re: Need help identifying faulty transistor & replacement

Read immediately under "Commonly failed components"
http://webdevsys.com/d530psuRepairNotes.htm
And of course verify the cross reference is correct.....
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Old 05-20-2011, 11:06 AM   #6
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Default Re: Need help identifying faulty transistor & replacement

Found this but it's not in a real datasheet..........
http://www.200ic.com/stock/Suppliers-2SK3548.html

2SK3548 Datasheet:
Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: The inputs (IN1, IN2) are protected by shunt diodes to VSS and VDD. If the inputs are driven beyond the rails, the current should be limited to less than 10mA. Note 3: The 2SK3548 output (VOUT) is high impedance and can be overdriven, either sinking or sourcing current, to the limits stated. Note 4: The 2SK3548C/2SK3548I are guaranteed functional over the operating temperature range of C 40C to 85C. Note 5: The 2SK3548C is guaranteed to meet specified performance from 0C to 70C. The 2SK3548C is designed, characterized and expected to meet specified performance from C 40C to 85C but is not tested nor QA sampled at these temperatures. The 2SK3548I is guaranteed to meet specified performance from C 40C to 85C. Note 6: High speed automatic testing cannot be performed with CAVE = 10F. The 2SK3548 is 100% tested with CAVE = 22nF. Correlation tests have shown that the performance limits above can be guaranteed with the additional testing being performed to guarantee proper operation of all the internal circuitry.

2SK3548 Suppliers:
Key reatures include a low power dissipation of 375mW and TTL-compatible outputs. A wide analog input bandwidth of 8MHz (C3dB) allows operation without the need of a sample- hold. Also, single +5V supply operation is obtainable with an input range of +3 to +5V, eliminating the need for an additional power supply. A 0 to C2V input range is available with 5V supply operation.

2SK3548 On stock:
A typical application of the TV-SAM is a real-time interfield image processing combined with flicker reduction. This can be achieved, for example, by writing and reading with 13.5-MHz clock rate via port C and B and by simultaneously reading port A with 27-MHz double speed clock. A main cycle of 4 consecutive RE cycles of transfer is needed:
• Low Ohmic Values: 0.01Ω to 1.0Ω • Low Temperature Coefficient of Resistance (TCR): 10ppm/C, nominal (- 55C to + 125C, + 25C Ref.) • Tight Resistance Tolerance: to 0.1% • High Power Rating: 1 watt at + 85C • Current Rating: 5 Amperes maximum • Low Thermal EMF: 0.05V/C typical • Low Current Noise: - 40dB • Low Voltage Coefficient: < 0.1ppm/V • Non Inductive: < 0.08H
Function, Pinout, and Drive Compatible With FCT and F Logic Reduced VOH (Typically = 3.3 V) Version of Equivalent FCT Functions Edge-Rate Control Circuitry for Significantly Improved Noise Characteristics Ioff Supports Partial-Power-Down Mode Operation Matched Rise and Fall Times Fully Compatible With TTL Input and Output Logic Levels ESD Protection Exceeds JESD 22 C 2000-V Human-Body Model (A114-A) C 200-V Machine Model (A115-A) C 1000-V Charged-Device Model (C101) 64-mA Output Sink Current 32-mA Output Source Current 3-State Outputs
− The order of the two start bits must be 0, then 1 in any frame; otherwise, the data rate will not be detected correctly. The period between the falling edge of the first start bit (ST0) and the rising edge of the second start bit (ST1) is measured to generate an internal-clock synchronized data stream.
The 25CTQ center tap Schottky rectifier series has been optimized for very low forward voltage drop, with moderate leakage. The proprietary barrier technology allows for reliable operation up to 150 C junction temperature. Typical applications are in switching power supplies, converters, free-wheeling diodes, and reverse battery protection.
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Old 05-21-2011, 06:33 PM   #7
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Default Re: Need help identifying faulty transistor & replacement

PCBONEZ, thank you. Appreciate it.

From yours & Rtech's help, i am now going to place order on the parts to replace them. Hopefully no other components are failing or are 'walking wounded'. Lets see how it goes when the parts arrive.
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Old 10-24-2011, 11:01 PM   #8
antonio herrera
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Default Re: Need help identifying faulty transistor & replacement

i have the same monitor but mine monitor it's not that bad i have replace the cap& the resistance n still not working i need more help on fixing my monitor?
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Old 10-25-2011, 09:28 AM   #9
newbie1
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Default Re: Need help identifying faulty transistor & replacement

Quote:
Originally Posted by antonio herrera View Post
i have the same monitor but mine monitor it's not that bad i have replace the cap& the resistance n still not working i need more help on fixing my monitor?
See >> this link for the parts to change. Oh & good luck!........ because mine is not having the best of luck..
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Old 01-17-2012, 09:28 PM   #10
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Default Re: Need help identifying faulty transistor & replacement

See this link for those who wanted to use the power adaptor mod version
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