Samsung LE32C450E1W don't start

[claudegu]

Hello and sorry for my english, I'm french.

When I plug my tv, the red light goes on, then if I use the remote to start the TV, nothing happend.

The power card is a BN44-00338a



Without the Main board plugged, the backlight goes on
And I have these values:

On the CN802:
1/3/5 : 12,1V
7/9 : 0V
11/13/15/17 : 12,2V
2 : 0V
4/6/8 : 0v,
10/12 : 0V
14/16 : 5,2V
18 : 0,8V


CN803:
1/2/3 0V
4 : 1,2V
5/6/7/8/9 : 0V
10/11/12/13/14 : 24,6V

On the big capacitor 395V DC

If I plug the Mainboard to the power board, the back light goes off and the 13V and 5V go up and down and I heard a tik tik about once every second.
On the big capacitor the voltage goes down to about 320V and up to 390V evrey second too.

I have tried to remove the mainboard and put loads to the 13V and 5V of the power board, evrery thing is fine with the 13V and the 5V they don't drop.

I have checked the ampere on the 13V and the 5V between the main board and power board, 400mA on the 13V and 200mA on the 5V.

If you may help me, I would be very happy.

[claudegu]

Re: Samsung LE32C450E1W don't start

I still need help

[Alastair E]

Re: Samsung LE32C450E1W don't start

Mainboard fault I would think.

You've proved the PSU and the Backlight systems are working--Not much else left!

[claudegu]

Re: Samsung LE32C450E1W don't start

Thank you for the reply.
About the main board, what should I test ?

[martino]

Re: Samsung LE32C450E1W don't start

On powerboard,replace capacitor CM808,very common failure on these...

[claudegu]

Re: Samsung LE32C450E1W don't start

Hello Martino, thanks for your reply.
I had a look and find no CM808, I found a
CP808 22uF 50V is it that one?

My supply board is a CN07BN44-00338ASE

[tom66]

Re: Samsung LE32C450E1W don't start

On powerboard,replace capacitor CM808,very common failure on these...

As the power board appears to be working there would be little point in doing this.

[claudegu]

Re: Samsung LE32C450E1W don't start

Martino : OK I found it, it is a CMS under the board, just at the output of an opto.
TOM66: what should I do for the main board, is there some points to test ?

Thanks for your help

[martino]

Re: Samsung LE32C450E1W don't start

I apologize, reading too fast,I thought you had the BN44-00338b,but you have the A version....So ignore my post,Tom66 you stand correct!!

[tom66]

Re: Samsung LE32C450E1W don't start

the particular fault applies to both 338A/338B and would be correct if the voltages were low or gone, so you weren't too far off.

[martino]

Re: Samsung LE32C450E1W don't start

The fluctuating 5 and 13volts got me on that. Quickly scanning over the board number sealed the deal for me. Haha.
I need to learn how to slow down, not only with soldering at 3am but also reading posts. Lol.

[stj]

Re: Samsung LE32C450E1W don't start

it's a shorted part,
start by checking all the diodes, regulators & fets.

[claudegu]

Re: Samsung LE32C450E1W don't start

About the CM808, I have removed it, just in case, but nothing happend.

STJ: I will do that, but when I plug a 13V and 5V supply on the main board, my supply says: 400mA for the 13V and about 200mA for the 5V so I thought there was no shortage.
But is it enough to provide 13V and 5V to the main board to get it "on" ?

[martino]

Re: Samsung LE32C450E1W don't start

About the CM808, I have removed it, just in case, but nothing happend.

STJ: I will do that, but when I plug a 13V and 5V supply on the main board, my supply says: 400mA for the 13V and about 200mA for the 5V so I thought there was no shortage.
?

AH!!!....that's how you load checked.....
I would put CM808 back in and replace CM801s(see pic,I circled it)....
It's 22nF 1000v cap......
And you can't just take it out and try,as this cap is sitting in series......

[claudegu]

Re: Samsung LE32C450E1W don't start

Martino : my load check isn't valid?
OK, I will put back the CM808 and replace the CM801, but I have to get one.

Thanks for your help

[claudegu]

Re: Samsung LE32C450E1W don't start

Martino,

Is this one Ok ?

[martino]

Re: Samsung LE32C450E1W don't start

Do you have a local electronic hobby store? I see you are in france,the cap is pretty regular,I would be hard pressed if they wouldn't have them....
Take old one with you,always helps Or the france ebay???

[tom66]

Re: Samsung LE32C450E1W don't start

I would be surprised if the cap is bad; you can get it from Farnell or probably eBay though (no concern about counterfeits with poly caps, in general.)

[martino]

Re: Samsung LE32C450E1W don't start

Tom66. Plz double check before I give him bad advise.( pretty new at this still).
The load test he did was by applying 5 And 13 volts to the main board with an external psu and measured amp draw with that. He didn't "load" the psu itself. Making me think it IS the classic cap fault. I put both schematics beside eachother for location of cm808 and on his that would be the one I stated here.

[tom66]

Re: Samsung LE32C450E1W don't start

I think he is using an amp-meter in series with original power board.