Samsung 192n

[Sam]

Can someone tell me the capacitance on the secondary +12v and +5v rails of this power supply.

[davmax]

Re: Samsung 192n

Googled: This is a 19" black monitor. Have you opened up this monitor? This should reveal what you need to know.

[Sam]

Re: Samsung 192n

Yes I have it open, someone has worked on it before. It has mixed CapXon caps, on the 12v it has (two) 1000uf 25v and (one) 470uf 25v..On the 5v it has (two) 2200uf @ 25v and (one) 470uf @ 25v..All 12v are in parallel , same with the 5v.

[sceva]

Re: Samsung 192n

I just opened a 192N and have the same question as the original poster. On the 5v track there are three caps in parallel. Two are 2200uf @ 10v, and the third one was 470uf @ 25v. Is this 'normal'?

I will get pics and submit tomorrow...

[sceva]

Re: Samsung 192n

Very strange LCD... When it is not working, the power indicator is flashing yellow or orange. I get 7.5v coming off the PS to the main board where I should have 12v, and 3.6v where I should have 5v.

So far I have:
Tested all the caps and replaced the 3 small ones with good caps. They were a little high with esr meter, but not failing.

Reflowed solder on all the pins on the PS.

The larger cap right below R14 was originally a 470u/25v. It is in series with the two beside it, so I replaced it with the same type as the two - 2200u/10v. Not sure if that was wise or not.. hopefully someone can let me know...

Retested the board after replacing caps and same results. I then removed the cable from the PS to the main board and got the same low voltages.

I reconnected the Main board and removed the cable from the main board to the inverter board and retested - and got 15v and 5v!

Then I reconnected the inverter cable, turned it on, and it works... with 12.6v and 5v coming from the power supply.

I then moved things around, messed with cables, trying to get it to fail again but could not... Any ideas?

[sceva]

Re: Samsung 192n

The larger cap right below R14 was originally a 470u/25v. It is in series with the two beside it, so I replaced it with the same type as the two - 2200u/10v. Not sure if that was wise or not.. hopefully someone can let me know...

It is still working. Just wondering if I should leave the 2200u cap in place, or put the 470u/25v back in. I have done some reading and realized that when they are in parallel that the capacitance is the sum of all the caps, so maybe they 470 was by design?

[sceva]

Re: Samsung 192n

It is still working. Just wondering if I should leave the 2200u cap in place, or put the 470u/25v back in. I have done some reading and realized that when they are in parallel that the capacitance is the sum of all the caps, so maybe they 470 was by design?

I am thinking about putting the original 470u/25v back in if no one has any other suggestions.... I am not learned enough to re-engineer boards yet!