Samsung UE40F6320AK on / off boot loop problems

[Bloopeta]

Re: Samsung UE40F6320AK on / off boot loop problems

If you disconnect the power supply from the main board and jumper A5V to PWR ON/OFF using a 1K resistor and switch on, does the B5V and B13 supplies come on.

1k resistors came this morning, no difference to B5V and B13V when jumper A5 to pwr on/off, exact same result with or without resistor.

Does it matter which way round resistor goes?

[nomoresonys]

Re: Samsung UE40F6320AK on / off boot loop problems

With power cord unplugged, unplug cable from powerboard to mainboard, plug power cord back into powerboard, backlights should come on and stay on=powerboard selftest if backlights don't come on the problem is in powerboard or backlights which need to be fixed first before messing with mainboard which may be ok or not.

[Bloopeta]

Re: Samsung UE40F6320AK on / off boot loop problems

With power cord unplugged, unplug cable from powerboard to mainboard, plug power cord back into powerboard, backlights should come on and stay on=powerboard selftest if backlights don't come on the problem is in powerboard or backlights which need to be fixed first before messing with mainboard which may be ok or not.

Hi, Ive already unplugged main board and the backlights dont stay on, still just clicks and comes on for a second, then immediately off again, and repeats over and over.

Even if nothing at all is plugged into the powerboard, except the mains power cable, it still clicks repeatedly.

Would the whole powerboard need replaced, or just some capacitors etc?
I have read that around the time this TV was produced Samsung were known for fitting undervalued capacitors??

[nomoresonys]

Re: Samsung UE40F6320AK on / off boot loop problems

Check all the diodes, could try heating the powerboard a small section at a time with a hairdryer, go over the whole board and those brown caps the little blue ones too, see if the tv tries to turn on or anything changes.

[Bloopeta]

Re: Samsung UE40F6320AK on / off boot loop problems

Check all the diodes, could try heating the powerboard a small section at a time with a hairdryer, go over the whole board and those brown caps the little blue ones too, see if the tv tries to turn on or anything changes.

Tested Diodes, all seem fine.

Whilst on diode mode, I touched all the resistors, all beeped, except one, not sure if that means anything? Lol

[Bloopeta]

Re: Samsung UE40F6320AK on / off boot loop problems

Check all the diodes, could try heating the powerboard a small section at a time with a hairdryer, go over the whole board and those brown caps the little blue ones too, see if the tv tries to turn on or anything changes.

Just tried what u said n gently warmed the power board with a heatgun, after a minute or two the TV has come on as normal!!

[budm]

Re: Samsung UE40F6320AK on / off boot loop problems

PS-ON signal.
So PS-ON is stable? I still think that for the PS-ON to be going and down, the A5V has to be going up and down also because the PS-ON pull-up resistor is connected directly to the A5V as shown in the picture.

[nomoresonys]

Re: Samsung UE40F6320AK on / off boot loop problems

Hmm, now maybe try narrow down the area heated to when it comes on, thinking its a bad cap, maybe heat the electro caps small section at a time see if it comes on then the blue ceramic. Could test the caps it's hard to know the esr tho without an esr meter.

[budm]

Re: Samsung UE40F6320AK on / off boot loop problems

I would try just heating up the standby power supply section and see especially around those two lytics caps, https://www.badcaps.net/forum/attach...3&d=1571254351

[nomoresonys]

Re: Samsung UE40F6320AK on / off boot loop problems

Is that the right picture Bud it's a resistor circled?

[budm]

Re: Samsung UE40F6320AK on / off boot loop problems

Is that the right picture Bud it's a resistor circled?

This OP picture? https://www.badcaps.net/forum/attach...3&d=1571254351

[nomoresonys]

Re: Samsung UE40F6320AK on / off boot loop problems

Ok, I see, you mean he should start in that area.

[Bloopeta]

Re: Samsung UE40F6320AK on / off boot loop problems

Hmm, now maybe try narrow down the area heated to when it comes on, thinking its a bad cap, maybe heat the electro caps small section at a time see if it comes on then the blue ceramic. Could test the caps it's hard to know the esr tho without an esr meter.

I only have a multimeter, and dont know how to test caps with that?

[Bloopeta]

Re: Samsung UE40F6320AK on / off boot loop problems

I would try just heating up the standby power supply section and see especially around those two lytics caps, https://www.badcaps.net/forum/attach...3&d=1571254351

I will try in the morning, as its almost 11pm in UK

[budm]

Re: Samsung UE40F6320AK on / off boot loop problems

Ok, I see, you mean he should start in that area.

That resistor is 82K Ohms, it is for the RC snubber network for that standby power supply section, I just do not understand why people will use diode mode to test resistor.

[Bloopeta]

Re: Samsung UE40F6320AK on / off boot loop problems

That resistor is 82K Ohms, it is for the RC snubber network for that standby power supply section, I just do not understand why people will use diode mode to test resistor.

Wasnt testing them as such, but as I was there testing the diodes, I thought id see what happened if I tried on the resistors

[Bloopeta]

Re: Samsung UE40F6320AK on / off boot loop problems

It would appear, that heating this section is what allows it to start

[budm]

Re: Samsung UE40F6320AK on / off boot loop problems

The LED driver/power supply section. If you disconnect the LED connector, will it be in boot loop?

[Bloopeta]

Re: Samsung UE40F6320AK on / off boot loop problems

The LED driver/power supply section. If you disconnect the LED connector, will it be in boot loop?

Yes, still loops with LED feed plug disconnected

[budm]

Re: Samsung UE40F6320AK on / off boot loop problems

Can I see good clear hi-res of the whole bottom side of your power supply board?