Samsung ln46d610 power cycling

[microvibe]

I have a 46d610, plug it in starts to power cycle hear the chime backlight tries to light then repeat. If I unplug inverter boatd it will power up and stay on I don't see video with flashlight but I do have voltages.
13v line is 12.4v
All 5v are 5.2
Pdimm is 1.6v
Det-5v is 2.5v not sure this a problem.
On the inverter connector pin 1 and 3 high and low don't go past 5-6v.

I have 392v on main caps. Not sure how test inverter board don't have transformer tester.

[budm]

Re: Samsung ln46d610 power cycling

Can we see the rest of other boards?

[microvibe]

Re: Samsung ln46d610 power cycling

Here is pic of the rest boards curtosey of shopjimmy better quality

[microvibe]

Re: Samsung ln46d610 power cycling

Bump

[dick_barton]

Re: Samsung ln46d610 power cycling

What is the BLU_ON voltage when you start up with the inverter board connected and also what voltages do you have on CNI801 connector.

[microvibe]

Re: Samsung ln46d610 power cycling

Blon is 5.2v

Cni801
Ld is 10.6
13v is 12.4
Cnt 11.2v
Fet low spikes to 4-6v
Fet high spikes to 4-6v

[budm]

Re: Samsung ln46d610 power cycling

Did you do any resistance testing on the High Voltage winding (there are two HV winding for each transformer) of those three inverter transformers to see if they all have about the same resistance?

[dick_barton]

Re: Samsung ln46d610 power cycling

The board shows a legend saying CNI801 High (273V) AC and CNI801 Low (193V) DC

[budm]

Re: Samsung ln46d610 power cycling

The output of the power supply board that goes to the High Voltage transformer is AC high frequency high Voltage (273V) to drive the primary side of the high Voltage transformers instead of the usual 24VDC power supply for the driving circuit of typical inverter board, the drive circuit is on the power supply board instead.

[microvibe]

Re: Samsung ln46d610 power cycling

Resistance is same on all transformers. 1.3 on 2k setting

[budm]

Re: Samsung ln46d610 power cycling

Do you have cap meter to check the capacitance of the cap CI818 (2W 474K).

[microvibe]

Re: Samsung ln46d610 power cycling

No I don't. Don't know anyone locally has one ethier. The TV tries to start up you hear the startup chime and the back lights try to come on course they're not getting enough voltage and then reboots again

[microvibe]

Re: Samsung ln46d610 power cycling

You think it's the 2w474k cap same issues as the Samsung c and d series lcd's. This one doesn't look swollen .

[budm]

Re: Samsung ln46d610 power cycling

I am not sure yet about the relationship of that inverter driver circuit and the rebooting of the TV because the LD (Lamp Detect) is above 10V DC.
The cap does not have to be swollen to be bad.

[microvibe]

Re: Samsung ln46d610 power cycling

With the main board disconnected the back lights come on and stay on. In the main board is connected then it power Cycles detect 5 volt pin shows 2.68 volts where does that get its Bible Source from

[Nick's Tvs]

Re: Samsung ln46d610 power cycling

If disconnecting the main board allows you to get good back-light, it sounds like you might have an issue on your main board. Was there a lightning strike or power surge around the same time this issue occurred? If so, I would suggest you check for a low reading on the surface mount capacitor with location number C601 to the right of the HDMI chip IC601. I attached a photo with this post outlining where the cap is located. If it reads anything below 400 ohms, then you have a bad HDMI chip.

[microvibe]

Re: Samsung ln46d610 power cycling

No power spike that I know of measures 690ohm one way

[Nick's Tvs]

Re: Samsung ln46d610 power cycling

Okay that means your HDMI chip is fine then. Generally when we receive these boards with cycling issues it is due to that chip being shorted from a lightning strike or surge. Sometime they also simply overheat and fail.
Thought I would give it a try.
Not sure exactly then.

[microvibe]

Re: Samsung ln46d610 power cycling

Ok rechecked cap in continuity or diode mode instead 2kohm mode cap read 168 one way and 0L the other . If chip is bad can I remove it then boot up tv?

[budm]

Re: Samsung ln46d610 power cycling

What Voltage do get now at DET-5V opin when you run the power supply board by itself?
Look at some of the Samsung power supply board schematics, it shows that it should be close to 5VDC for normal operation to tell the main board that the backlights circuit is OK.
Monitor that pin to see if it changes state at all when TV is turned off and when turned on.