Hitachi 43HB6T62 No Power

[trunks81]

Got this tv in and it is struck by lightning,
The main fuse is oke and i dont have an short when i power the set on.
I also have like 300V on the main cap Also tested the diodes on the board and they are fine

[dick_barton]

Re: Hitachi 43HB6T62 No Power

Check the solder joints on CN4 are all good.

[R_J]

Re: Hitachi 43HB6T62 No Power

First check if you have +12VCC on CN4 if not, then check the primary circuit.

The main cap voltage is checked using HOT ground, so measure the voltage ACROSS the main cap. Hot ground is the anode of D147. Then with your meter negative on hot ground, check the voltage on the drain (center lead) of the mosfet, you can also check that voltage on the two ferrite beads directly in front of the mosfet. If you have the same voltage as across the main caps, then check if you have VCC voltage for the main ic. This voltage can be checked across C115 47µf/50v

[CapLeaker]

Re: Hitachi 43HB6T62 No Power

300V on the main cap doesn't cut it when the TV is on. It should be closer to 400V. That means: the PFC isn't working.

[trunks81]

Re: Hitachi 43HB6T62 No Power

Hello

There is no +12VCC also no 5VSTB,
Also the voltage on C115 is 20V,
voltage on the mosfet is 92V

[CapLeaker]

Re: Hitachi 43HB6T62 No Power

you have to fix the 5vstb first.

[trunks81]

Re: Hitachi 43HB6T62 No Power

Which section do i need to check for that ?

[budm]

Re: Hitachi 43HB6T62 No Power

According to the schematic, this power supply board has an always on 12VCC, 24VCC, 5VSTBY (generated by 12VCC).

Does your board has U101 as FAN5300?
Do you get any DCV between the two legs of C169?

[trunks81]

Re: Hitachi 43HB6T62 No Power

U101 is present only according to schematics it is an FAN6300
DCV between C169 is 12.3V

[budm]

Re: Hitachi 43HB6T62 No Power

U101 is present only according to schematics it is an FAN6300
DCV between C169 is 12.3V

That means the U101 SMPS IC is working so you should have +12VCC at connector CN4 PIN 10, 11, and 12 according to the schematic, do have them?

[trunks81]

Re: Hitachi 43HB6T62 No Power

I dont have +12VCC at pins 10,11,12

[budm]

Re: Hitachi 43HB6T62 No Power

What DCV do you have on C532? 24V?

[budm]

Re: Hitachi 43HB6T62 No Power

BTW, after tracing out the board, the +5VSTBY parts are not installed, I do not see Q104, D113 installed on the board so there will be no +5V STBY.

[trunks81]

Re: Hitachi 43HB6T62 No Power

On C532 ian getting 28V ?

[budm]

Re: Hitachi 43HB6T62 No Power

I dont have +12VCC at pins 10,11,12

Do you have +12V on C109?
Are you sure you count the CN4 pins correctly?

[budm]

Re: Hitachi 43HB6T62 No Power

On C532 ian getting 28V ?

That is fine for now because the 24V output is not used for feedback regulation, the circuit only monitor +12V output and uses it to maintain the +12V output..

[trunks81]

Re: Hitachi 43HB6T62 No Power

Iam getting 12,3V on C109
only the next does not make any sense to me ..
iam getting 12,3V on the next pint 6,8,10 and gnd is 4

[budm]

Re: Hitachi 43HB6T62 No Power

Iam getting 12,3V on C109
only the next does not make any sense to me ..
iam getting 12,3V on the next pint 6,8,10 and gnd is 4

You count it wrong.

You need to turn the picture 180 degree to match the bottom view of the board. https://www.badcaps.net/forum/attach...0&d=1598424914

As you can see, C109 (positive leg I marked at +12V is connected to pin 10, 11, and 12 of CN4.

Use negative leg of C109 for ground then check check the Voltages on the pin again, look at how I labeled the pins for you for top view and bottom view of the board for CN4.

[trunks81]

Re: Hitachi 43HB6T62 No Power

my bad i was misguided by the arrow on the connector..
But no i see there is also an little dot at pin 1

Now i have 12.31V on pins 10,11,12 on GND 4,6,8

[budm]

Re: Hitachi 43HB6T62 No Power

So the the 12V power supply for the main board is fine, the 24V for the backligts circuit is fine.
So now you need to find out what you have on STBY pin 3, BL-ON/OFF pin7, PWM-DIM on pin 7 when TV is off and when TV is turned on.