Replacing Power Mosfet in Toshiba 32L1300UC LCD TV power supply?

[kodiac]

I would like to know if it is possible to replace a UTC7N65 power mosfet with a STP7NK80ZFP power mosfet?

If no - is there is a substitute for the UTC7N65 that can be installed in a Toshiba 32L1300UC LCD TV power supply?

Thank You

[R_J]

Re: Power Mosfet

The current is a bit low, 5.2 amp vs 7.4 amp
Digikey has this one, DMG9N65CTIDI-ND, looks a bit closer?

[kodiac]

Re: Power Mosfet

Thank You very much sir.

Would it be possible to use a substitute Mosfet with internal Zener diodes as opposed to normal diodes?
How does the Zener diodes affect the performance of the Mosfet?

Thank You

[kodiac]

Re: Power Mosfet

Can I replace the 7n65 with a MMD70R600P MosFet?


Thank You

[kodiac]

Re: Power Mosfet

Anyone have a Toshiba 32l1300 LCD TV that has no picture, no power - no standby led, blank screen?

Just like to know how it was brought back to life?


Thank You

[R_J]

Re: Power Mosfet

What was wrong with the fet? was it shorted? Was it SQ801? if not, do you get any voltages on the plug going to the main board?

I do see an eeprom available for this model, that might be the cause of the problem.

[kodiac]

Re: Power Mosfet

Thank You for your reply.

Do You have a schematic for the Toshiba 32L1300?

[R_J]

Re: Power Mosfet

No I don't

[kodiac]

Re: Power Mosfet

Can You show me the link to the firmware / Eeprom dump for the Toshiba 32L1300 please?

Thank You

[R_J]

Re: Power Mosfet

I had the wrong main board, the eeprom would be for a VTV-L40711 main board
Why don't you post the voltages I asked for, that way maybe it can be determined where the problem is.

[kodiac]

Re: Replacing Power Mosfet in Toshiba 32L1300UC LCD TV power supply?

OK I will do that.

Thank You

[kodiac]

Re: Replacing Power Mosfet in Toshiba 32L1300UC LCD TV power supply?

Would the MMD70R600P be a replacement for the 7n65?

Thank You

[R_J]

Re: Replacing Power Mosfet in Toshiba 32L1300UC LCD TV power supply?

the MMD70R600P is a surface mount component, not the same mounting as the 7n65

[kodiac]

Re: Replacing Power Mosfet in Toshiba 32L1300UC LCD TV power supply?

The 70R600P I have is in the TO-220 package.

Power Supply Board and Voltages attached.

[budm]

Re: Replacing Power Mosfet in Toshiba 32L1300UC LCD TV power supply?

What did you use for the meter GND ref when you made those Voltage measurement in the HOT side of the circuit? Chassis?
You need to use the negative leg of the main filter cap as the GND ref when working in the hot side of the circuit.
Please provide the pictures of the bottom side of the board so we can see the SMPS IC?
Was the original MOSFET shorted out? BTW, already asked in post #6 but no reply.

[kodiac]

Re: Replacing Power Mosfet in Toshiba 32L1300UC LCD TV power supply?

"What did you use for the meter GND ref when you made those Voltage measurement in the HOT side of the circuit?"

The meter GND ref was the silver Philips screw ( Chassis ) in the top right hand corner of the picture next to the AC Power connector.

The Bridge Rectifier voltage was pins 1 + and pin 4 - = 168v.




" Was the original MOSFET shorted out? "

Yes the original MOSFET was shorted out.


I'll post new voltages and pictures.

[budm]

Re: Replacing Power Mosfet in Toshiba 32L1300UC LCD TV power supply?

If the MOSFET shorted out, it could have damaged the SMPS IC too.

[kodiac]

Re: Replacing Power Mosfet in Toshiba 32L1300UC LCD TV power supply?

Top and Bottom of Power Supply Board.

Meter GND - Capacitor - .

[kodiac]

Re: Replacing Power Mosfet in Toshiba 32L1300UC LCD TV power supply?

Thank You

[R_J]

Re: Replacing Power Mosfet in Toshiba 32L1300UC LCD TV power supply?

If the mosfet was shorted, it is a very good chance R815 is also open also like budm said. U801 could be damaged, If the fet Drain shorts to Gate the full 160V could be applied to the ic.