LN40A530 Samsung LCD TV long to start...Capacitor issue ?

Did you fix the issue? Seems like I have the same problem Thanks

Your symptoms are classic for bad caps and unlike a fine wine, this will no t improve with age

Many times there is a small ceramic cap i parallel with the 'lytic cap that will cause the ESR meter to say it's OK when it isn't. If the meter says i t's bad it very likely IS.

Over the years I've observed that when I find a certain value/Voltage that has one failure in a unit, any other identical caps should be replaced as w ell. Generally when you get to the point of replacing some caps it's a good idea to replace ALL the 'lytic caps. Once you have the unit open it would be silly to gamble and maybe have to do it again.

Personally I prefer SMT caps as they're quicker to remove. I treat through hole and SMT the same. I destroy the cap by cutting it apart and with throu gh holes, cut the leads on the component side down to the board with a flus h cutter and the use an old solder sucker to pull the lead out the solder s ide. Remember to clean off any acid residue before installing the new caps and then the flux when you're done.

Also BUY THE BEST CAPS YOU CAN FIND. Your tine us way more expensive than e ven the best caps. DigiKey, Mouser, Newark and Allied carry good stuff. I u sually use DigiKey because their website is more complete than the others a nd I generally get Panasonic caps looking for highest ripple current, highe st hour and temperature.

I've found the best test for caps is to stick a scope across them and see what's happening to the voltage. Isn't hard to tell if that node has an issue. If there are multiple caps, it won't tell you which, but change 'em all anyway.

One thing that most people don't seem to realize is that a bad cap can let the voltage go WAY HIGH. If you're switching down from 20V to 3.3V, you can get

20V spikes on that node with bad caps. I've had monitors DIE from the spikes.

The result of all that is... Turn the thing off till you fix it. It may work after

10 minutes this time, but, eventually you may kill it.

People over-do the bad cap thing - but this one is easy.

Yes, it's the caps. Replace any that appear bulged at the top. The rest are probably OK for the next several years at least.

Use high quality low-esr types.

I agree it's potentially damaging to keep using it.

Mark Z.

This thread is 3 years old, but I'll bet the problem was not the power supply. I have had to rebuild dozens of Samsung main boards to solve this problem (and no, it's not caps).

The easy way to identify this is to remove the main, pre-heat it away from the TV with a heat gun or hair dryer, then reinstall. If it starts immediately, the main is the problem.

Authorized Samsung servicer. The exact symptom given is well-known.

It was the caps, I've no doubt.

"rebuilding the main board" - I doubt it.

No doubt eh? Here's what the OP said: "I had checked all capacitors on t he power supply board and they are reading all good (value/ESR). I even *ch anged* them and same thing."

Tell me Mark; how many times would you change the same capacitors before fi nally conceding they weren't the problem?

I've recapped thousands of Samsung power supplies, and have had a few dozen main boards in the MX10 series that would have the exact same symptom (slo w start, cycling, better when warm). If you're a Nesda member (doubt it), you'll find the solution to stubborn Samsung MX mains there. Most professi onal servicers won't put every solution to a problem on youtube. I'm no ex ception.

No doubt eh? Here's what the OP said: "I had checked all capacitors on the power supply board and they are reading all good (value/ESR). I even

*changed* them and same thing."

Tell me Mark; how many times would you change the same capacitors before finally conceding they weren't the problem?

I've recapped thousands of Samsung power supplies, and have had a few dozen main boards in the MX10 series that would have the exact same symptom (slow start, cycling, better when warm). If you're a Nesda member (doubt it), you'll find the solution to stubborn Samsung MX mains there. Most professional servicers won't put every solution to a problem on youtube. I'm no exception.

************************************************************************** Excuse the skepticism. I've seen my share of main boards, even after replacing the defective caps. Generally just replace the boards, though. "thousands" of power supplies might be overstating it just a bit, though...

mz

Sorry about that - I must have been too lazy reading the original post.

Appearances to the contrary notwithstanding, I'm really not a troll looking for arguments.

I would not, however, repeatedly change caps if the main board was indicated. In fact, the caps would probably only get replaced in that situation if Samsung were covering it, which they were until recently. Then the caps, and if indicated the whole power supply gets replaced on Samsung's dime, and informing the customer there might still be a problem after those parts replaced.

Sometimes the whole supply fixes their issue even when I did not expect it to.

Dropped out of Nesda a decade ago. Maybe should not have; at the time there was no value for the stuff I was working on.

Not too interested in trying to fix main boards when they are often available at reduced prices from Union Electronics, ShopJimmy, and others. Often as low as 20 to 30 bucks for a pull.

Besides, my focus is audio. I just want to get the stuff running and get on to the next job.

Later.

mz

haven't heard about NESDA in a while.

Do they have any members that are not within 5 years of retiring?