Condensate burst on board BN-00506A

[Nawual]

Hello.
This board comes in a Samsung that does not turn on. I do not have any tension in the pins and I could see a condesador(CM804) busted near the IC but I do not know what value it has. I guess it will be 1KV but I do not know the capacity and I can not find the scheme.
Any ideas? Thank you






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[tvtimmy]

Re: Condensate burst on board BN-00506A

This smps is listed as a substitute for yours.

[Nawual]

Re: Condensate burst on board BN-00506A

Ok, thanks mate!
Do you think the ic will be wrong? Because that condesador has exploded is not very normal.

[stj]

Re: Condensate burst on board BN-00506A

is the fet o.k.??
(pins 1 & 3 shorted out or not)

if not then your lucky - btw i would upgrade that to 2KV - i'v seen 1KV ceramics fail a lot in some psu's

[Nawual]

Re: Condensate burst on board BN-00506A

What transistor do you mean? I often find it hard to translate from English into Spanish with the electronic terms.
I will put a 2kv capacitor, thanks for the advice

[stj]

Re: Condensate burst on board BN-00506A

the transistor is built into the i.c. between pins 1 & 3

[Nawual]

Re: Condensate burst on board BN-00506A

Ah, I'm an idiot. Of course, I know what you mean, I'm going to measure it.
Thanks again

[Nawual]

Re: Condensate burst on board BN-00506A

Hello again. I have changed the condenser and checked the FET with pins 1 and 3 and they are not shorted. But I did not have DC in the large filter condenser. Reviewing the hot zone I found the rectifier bridge broken and the protection fuse was open.
I have changed them and now I have voltage in the condenser but it does not reach the IC.
Suggestions?

[R_J]

Re: Condensate burst on board BN-00506A

The main filter connects to JP802, then to the primary winding of TM801s, and then directly to the ic, so check the connections and check the transformer winding.
Also check RM803 resistor (lift one end to check it) and check DM803 for short.

[Nawual]

Re: Condensate burst on board BN-00506A

Ok,i´ll check them and post here the results.
Thanks!

[Andrew F. Ali]

Re: Condensate burst on board BN-00506A

I would RJ but will also change all the following parts: IC801, DM803, CM808, RM803 and DM801.

[Nawual]

Re: Condensate burst on board BN-00506A

Thanks mate, but what´s RJ?

[Andrew F. Ali]

Re: Condensate burst on board BN-00506A

I meant I will follow RJ's advice.

[Nawual]

Re: Condensate burst on board BN-00506A

Ok, so following the advice of RJ, I have measured the tensions in the TM801s, and I have 0v in the red dots that I painted in the photo. The two pins left in the TM801s give me 300v. The DM803 has been removed and it is fine(red circle), and the RM803 is also fine.
In ohms the TM801s is isolated the primary of the secondary and in the primary I get very low resistance between the pins, so I discard it.
[IMG][/IMG]

[R_J]

Re: Condensate burst on board BN-00506A

Hello again. I have changed the condenser and checked the FET with pins 1 and 3 and they are not shorted. But I did not have DC in the large filter condenser. Reviewing the hot zone I found the rectifier bridge broken and the protection fuse was open.
I have changed them and now I have voltage in the condenser but it does not reach the IC.Suggestions?

You said you can NOT get the voltage from the "large filter condenser" to the ic, this is the path of that voltage.
Also check RM802 (2R2) resistor
Check if you have A5V (5 volts standby) on DM857

[budm]

Re: Condensate burst on board BN-00506A

"In ohms the TM801s is isolated the primary of the secondary and in the primary I get very low resistance between the pins, so I discard it." I wonder what he means by "so I discard it".

[Nawual]

Re: Condensate burst on board BN-00506A

Apologies for delaying to post the solution. I replaced the IC and the PSU came back to life. Thank you all for the help.

[tvtimmy]

Re: Condensate burst on board BN-00506A

Good job !

[azzzaoo6]

Re: Condensate burst on board BN-00506A

Ok, thanks mate!
Do you think the ic will be wrong? Because that condesador has exploded is not very normal.

hi ive just repaired this exact board the problem was 4 pin bridge rectifier was shorted tv was dead