Testing a Plasma PS without any boards connected?

[videobruce]

To trouble shoot what appears to be a bad Plasma PS, disconnecting all of the daughter boards, where should a load go and how much to have the supply up and running to check voltages?

[Alastair E]

Re: Testing a Plasma PS without any boards connected?

Yes--Its possible with some of them.

What make/model are you working on? The procedure is different for different makes....

Like-- some Samsung you would deck the PS-On with a 1K and apply the Std-by 5V to the Vs-On via 1K
Some LG you would supply 5V via 1k to RLY-On and PS-On as well as Vs-On.

Use a 240V 150-200W Incandecent Bulb as a load for the Vs to check it.....

IF its a Philips with I2C comms PSU--Bin It, you'll never get the PSU to run without the set connected!

So--It All Depends on Make and Model, and whether its even possible.....

[videobruce]

Re: Testing a Plasma PS without any boards connected?

LG 60PK250/550 from 2010
Using a load, is that with all the boards connected or disconnected?

[Alastair E]

Re: Testing a Plasma PS without any boards connected?

Thats with the PSU on the bench, connected only to the bulb and whatever is needed to get it to run.
--ie, Not in the set.

[videobruce]

Re: Testing a Plasma PS without any boards connected?

I happened to stumble across a "training manual" for a similar series set and there are two pages on testing under load that are written differently. The 1st says nothing about disconnecting it from the rest of the chassis. The 2nd version tells you to disconnect the connector to the main board. Nothing about removing the board from the rest of the circuit on either. ;

Using two 100 Watt light bulbs, attach one end to Vs and the other end to ground. Apply AC to SC101. If the light bulbs
turn on and VS is the correct voltage, allow the SMPS to run for several minutes to be sure it will operate under load. If
this test is successful and all other voltages are generated, you can be fairly assured the power supply is OK.

The other version is here;

With P813 disconnected from the Main board (P301) attach two 100 Watt light bulbs, attach one end to Vs and the other end to ground.
Apply AC to SC101. If the light bulbs turn on and VS is the correct voltage, allow the SMPS to run for several minutes to be sure it will
operate under load. If this test is successful and all other voltages are generated, you can be fairly assured the power supply is OK.
Note: To be 100% sure, you would need to read the current handling capabilities of each power supply listed on the silk screen on the
SMPS and place each supply voltage under the appropriate load.
Note: Placing the two 100 Watt light bulbs from Vs to Ground will assure the power supply will regulate with a load and no other Abnormal conditions may result.

[Alastair E]

Re: Testing a Plasma PS without any boards connected?

You asked--- 'Testing a Plasma PS without any boards connected?'

I said, Yes--some you can, and described how to do so.

You have maybe confused things by reading a manual that assumes the PSU is in the set--not on the bench.
--To do that procedure in the manual you'll need to disconnect the SUS boards but keep mainboard connected (so the micro can turn it on), put 150W 240V bulb on the Vs output of PSU.

Why do you think your PSU is faulty anyway?

Does any voltages come up, then die away on turn-on?, No STby 5V? no stdby red-light? What?

Whats happening? Any shorts on the Vs lines? blown fuses...?

Is this one of those LG 60" that have Two PSU's....? I dunno, Never ever seen any 60" for repair thankfully, would kill me to carry such an obscene monster up three flights of stairs anyway!

[videobruce]

Re: Testing a Plasma PS without any boards connected?

When plugged in, the standby light flashes twice and then dies. Nothing is coming off the PS as far as I can tell. No relay clicking.

It's a LG 60PK250. The supply looks clean, no burns, cold solder joints or bulged caps. Most all connectors where disconnected and the reconnected more than once in case it was a contact problem.

[Viejo]

Re: Testing a Plasma PS without any boards connected?

My 60pk250 only I can ear click and click the caps looks fine the resistor are good the fuses too my suspect is the regulator 3br1565jf some help to fix it