Sylvania LC320SLX No Power-Dead

[RON_CET]

Re: Sylvania LC320SLX No Power-Dead

how accurate is your dvm? also you do have a tolorance factor but either way you should read .39 ohms plus/minus i say 10% out of circuit

[kevinm34232]

Re: Sylvania LC320SLX No Power-Dead

I pulled 1 leg of all the resistors and R614 still read 0.000

[RON_CET]

Re: Sylvania LC320SLX No Power-Dead

R614 if you are reading this in circuit your going to read just like short due to one side is connected to ground,but what i do is remove one side of R614 to read and you should get about .3 ohms also the zener diodes there D608,D610,D612 should not read shorted to ground in circuit

[kevinm34232]

Re: Sylvania LC320SLX No Power-Dead

OK Ill try that. Also Im curious why the large resistor (R614 METAL OXIDE FILM RES. 2W J 0.39 Ω) gives me a resistance reading of 0.000?

[RON_CET]

Re: Sylvania LC320SLX No Power-Dead

yes if R604 is open it will stop set from powering ON, FYI i use a 680 ohm 1 watt to discharge most caps.

[kevinm34232]

Re: Sylvania LC320SLX No Power-Dead

This main on this cap definetely stays charged for awhile I found out when one of the pins touched the chassis

Anyway I heard about using a resisitor to discharge them, or a 100w light bulb, just curious what you all do..

Back to the TV as I said above, it seems R604 is bad although I haven't checked everything, could that one cause TV not to turn on?

[selldoor]

Re: Sylvania LC320SLX No Power-Dead

This isn't true... I know myself having touched plenty of caps and gotten plenty of shocks... They will self discharge slowly but it can take days.

Hmm? well I did say to check? - I do on BIG caps if im in a hurry and am pleased to say I have never been shocked at least not by a cap.

Anyway to answer the question as asked- it is all in here
http://www.repairfaq.org/sam/captest.htm#ctsdc

[tom66]

Re: Sylvania LC320SLX No Power-Dead

Modern capacitors have a resistor built in which normally discharges them in less than a minute. If you want to check to make sure just test the voltage with your meter - observe the polarity.

This isn't true... I know myself having touched plenty of caps and gotten plenty of shocks... They will self discharge slowly but it can take days.

[selldoor]

Re: Sylvania LC320SLX No Power-Dead

Also what would be a good resistor for discharging large capacitors? Or is there another way?

Modern capacitors have a resistor built in which normally discharges them in less than a minute. If you want to check to make sure just test the voltage with your meter - observe the polarity.

[budm]

Re: Sylvania LC320SLX No Power-Dead

From the SCH, the line voltage is fed to L601, L602, then it goes to 4 Diodes D601~604 bridge setup, the + output feeds R602, 603, 617 then the output feeds pin3 of the T601.
So check all those connections of all those component, and the resistors.

[kevinm34232]

Re: Sylvania LC320SLX No Power-Dead

What do you get at pin 3 of T601?

If I'm checking correctly 2.9v

[kevinm34232]

Re: Sylvania LC320SLX No Power-Dead

Let me resolder them and Ill check.

[kevinm34232]

Re: Sylvania LC320SLX No Power-Dead

Think I may have found something. Figured I check this group of resistors.

R604 tests open
R605 and R606 test good .392-.395
R614 the large resistor test 0.000?

R604-606 RES CARBON FILM T 1/4W J 390k Ω
R614 METAL OXIDE FILM RES. 2W J 0.39 Ω

Could R604 be the problem? What about reading on R614?

[budm]

Re: Sylvania LC320SLX No Power-Dead

What do you get at pin 3 of T601?

[kevinm34232]

Re: Sylvania LC320SLX No Power-Dead

Ok I have 4.6v at gate and 0v at drain using hot ground, so I guess I need to check diodes on primary side?

[kevinm34232]

Re: Sylvania LC320SLX No Power-Dead

OK thanks will do

[RON_CET]

Re: Sylvania LC320SLX No Power-Dead

if no diodes are shorted ,then using pin 8 of T601 as ground read dc voltage @ Drain of Q601 should have 134 vols DC when set plug in if you do have the 134 v there then check for 5.3v on gate of Q601 those two voltages must be present to kick start Q601 into oscillation to get the power supply running

[RON_CET]

Re: Sylvania LC320SLX No Power-Dead

going back to the diodes you checked for voltages also make sure none of those diodes are shorted use your diode scale on dvm to check

[RON_CET]

Re: Sylvania LC320SLX No Power-Dead

your resistor is ok then

[kevinm34232]

Re: Sylvania LC320SLX No Power-Dead

Nothing on 200k, but at 2M .396