LG 42PC5D Plasma no pic but sound

[tom66]

Re: LG 42PC5D Plasma no pic but sound

Yes, Q1, sorry didn't say.
The diodes may look bad, but diodes rarely become non-uniformly leaky. They almost always fail shorted. As do FETs.

[maddog310]

Re: LG 42PC5D Plasma no pic but sound

Readings from Q1

D+ S- OL
G+ S- OL
G+ D- OL
S+ D- 12. 14Mohms

Measured out of circuit, so it's bad? That heat sink was very hot.

Why would some diodes measure one way and others another way?

Thanx for all the help Tom66, without the help of you or others on this site and the internet, we probably wouldn't be able to fix our (my) electronic devices.

Where should i be looking now in relation to that fet, could that be the only part that went!
I did measure the IPM's and they show as no good also.

[maddog310]

Re: LG 42PC5D Plasma no pic but sound

ttt

[tom66]

Re: LG 42PC5D Plasma no pic but sound

Circuit can be different for some parts, so you will measure differently.
You need to test those Q's on diode mode.

[maddog310]

Re: LG 42PC5D Plasma no pic but sound

Q1 diode mode

D+ S- OL
G+ S- OL
G+ D- OL
S+ D- .482v

[maddog310]

Re: LG 42PC5D Plasma no pic but sound

Rechecked in diode mode.

Q1 tested out of circuit

D+ S- OL
G+ S- OL
G+ D- OL
S+ D- .482v
S+ G- OL

Q2 tested in circuit

D+ S- OL
G+ S- OL
G+ D- OL
S+ D- .469v
S+ G- .196v

I am going in the right direction, where should i be checking next?

[tom66]

Re: LG 42PC5D Plasma no pic but sound

Q1 good, Q2 appears bad - try retesting.

[maddog310]

Re: LG 42PC5D Plasma no pic but sound

Q2 tested out of circuit

D+ S- OL
G+ S- OL
G+ D- OL
S+ D- .460v
S+ G- OL

I guess both are good, that heat sink was very hot though.

Looking in the wrong place, likely the ipm's i checked earlier, which are a known weak point. I thought maybe something else might of been shorted.

Should i replace 1 or both ipm's?

Ysus # 6871QYH063A, module # AEF31675201(A) 0651SANY(P), Zsus # 6871QZH067(A), same module as above.

Do they have to replaced with exact match or with something close?
Any suggestions on replacements.

[tom66]

Re: LG 42PC5D Plasma no pic but sound

I don't know to be honest. Do you have screen glow in a dark room?

[maddog310]

Re: LG 42PC5D Plasma no pic but sound

No i didn't try it in a dark room.

I will put those fets back in and try.

[cudadave]

Re: LG 42PC5D Plasma no pic but sound

did anyone know what the F46J diode was? on the ysus board.

[cudadave]

Re: LG 42PC5D Plasma no pic but sound

does anyone know what the diode F46J is? on the ysus board.

[cudadave]

Re: LG 42PC5D Plasma no pic but sound

does anyone know what the diode f46j is? On the ysus board.for samsung plasma tv

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