65js9000 power supply bn44-00818a

[thuss]

Its a 65js9500 .Any advice would be helpful.

The backlights wont switch on.tv turns on and responds to the remote.

As per the other threads my mate has changed the 3110a chip, fuse and the primary and secondary mosfet he also replaced a couple of smd resistors a 1000 marked resistor and a 01c resistor.
All the voltages are present from the mainboard.

Prior to replacement of the above parts the fuse kept blowing inc mosfets.

Now nothing is blowing and there is voltage on most of the components however the voltage doesnt exceed 45v on the fuse and 65v on the mosfets.

The three main cap have only 45 volts on the legs. Which should be about 400v.

On the main transformers there is about 40v present on the ac side but nothing on the dc side.

One last question with ref to the the photo with the transformer what is that whiteish coloured component left of the transformer? Its reading continuously in comparison to the other similar components on the board.

Any advise would be helpful.

[diif]

Re: 65js9000 power supply bn44-00818a

The white thing to left of the transformer is a standoff, to reduce/remove the possibility of a short if the board bows.

[thuss]

Re: 65js9000 power supply bn44-00818a

Thanks

[dick_barton]

Re: 65js9000 power supply bn44-00818a

Check the two bridge rectifiers. Do you have 220v AC between the two AC pins and 310V DC between the positive and negative legs.
The rectifiers may have been damaged when the mosfets shorted.

There is a previous thread about this power supply

https://www.badcaps.net/forum/showth...ht=bn44-00818a

[thuss]

Re: 65js9000 power supply bn44-00818a

Yes seen and used that previous thread bridge rectifiers seem fine. Will check again thanks

One thing that was mentioned by my mate is that prior to replacing smd rm914 its pads with nothing in place were reading 100ohms and still reading 100 ohms after he installed a 01c resistor (10k).

[dick_barton]

Re: 65js9000 power supply bn44-00818a

Have you checked the inrush current limiter.in the blue box. I can't quite make out the number on the board.

What is the the item in the red box.

[thuss]

Re: 65js9000 power supply bn44-00818a

He did say that was strange but he couldnt work it out. He has removed the 01c smd res and rechecked it- it is fine and also the mosfet closer to the rm914 which is fine out of circuit but the outside 2 legs are reading short in situ

[thuss]

Re: 65js9000 power supply bn44-00818a

Have you checked the inrush current limiter. I can't quite make out the board number.

The board number bn44-00818a

[dick_barton]

Re: 65js9000 power supply bn44-00818a

Sorry, meant the component numbers on the board.

Have you checked the inrush current limiter in the blue box.

What is the the item in the red box.

[thuss]

Re: 65js9000 power supply bn44-00818a

Have you checked the inrush current limiter.in the blue box. I can't quite make out the number on the board.

What is the the item in the red box.

Yes he checked the ones you highlighted in the blue boxes. The red box please see attached photo its alkq3298 a relay

[dick_barton]

Re: 65js9000 power supply bn44-00818a

Do you know if it's being activated. Can you hear it click over?

Is the relay connected across the varistor. If it's like some other sets I think initially the line current passes though the varistor and brings up the standby voltage which then swithes the relay to short the varistor and allow full line current to flow through the relay contacts.

[thuss]

Re: 65js9000 power supply bn44-00818a

On the reverse side of the relay the two pins on the lhs slightly diagonally place are reading continuous but not with any other legs. The rhs legs do not read. Yes can hear it click and it is connected to the varister with voltages of 125

[dick_barton]

Re: 65js9000 power supply bn44-00818a

If it clicks then it must be operated. If I read you correctly the left side with the slightly diagonally placed are across the varistor. The RHS will be the supply to activate the relay so there must be some voltage being applied.

It appears to be a 5V, 8A relay.

With the set power off can you supply 5V to the RHS (coil) and use you meter set to ohms to check the resistance of the LHS contacts.

[thuss]

Re: 65js9000 power supply bn44-00818a

Sorry cant do- as my mates taken all the equipment but the varisters/ blue boxes you highlighted all had 125v on them but will get it checked again - ive read on the yhtead its the boost circuit that could be at fault?
My mate couldnt find dp801

[dick_barton]

Re: 65js9000 power supply bn44-00818a

The ac voltage readings prior to the bridge rectifier would be with respect to the neutral mains incoming and not the chassis.

[thuss]

Re: 65js9000 power supply bn44-00818a

Thanks will get them checked

[Storyteller12]

Re: 65js9000 power supply bn44-00818a

Double check all the parts your mate replaced and make sure he replaced them with the correct ones. Also I’ve gotten knock off parts before from eBay/ Amazon. It’s always good to order from a reputable place to make sure your getting genuine parts.

Sounds like the problem is coming from the primary side for sure though.

[R_J]

Re: 65js9000 power supply bn44-00818a

Check the DC voltage ACROSS one of the primary caps IE CP803S, What is this voltage? it should be around 325vdc in standby and around 385vdc when the power supply is ON.
If you have 385vdc (boosted pfc) then check that you have your STB5V (J899) These need to be working before anything else will.
As for RM914, with it removed you are measuring RM811 (100Ω), one end of RM811 connects through TM802CS to one end of RM814, the other end of RM811 connects directly to RM814.

Also when you are checking voltages you must know if they are in the primary or the secondary of the power supply. These use different grounds for the negative lead of your meter.
Primary voltages are checked using HOT ground (- leg of CP803S)
Secondary voltages use chassis ground or J891 for example.

[thuss]

Re: 65js9000 power supply bn44-00818a

Will do the check,stby was checked yesterday and it was about5.3 volt on the jumper you mentioned. My mate did put the + lead on the +terminal of the cap and the -lead on the -side will get checked again thanks

[thuss]

Re: 65js9000 power supply bn44-00818a

Sorry about late reply both bridge rectifier ac value is 242v
Both rectifier dc values is 249v.

The primary cap cp803s value whilst on standby 364 v dc whilst on 396 vdc