Samsung 40C5000QF intermittent won't power on

[smason]

This Samsung LCD goes through spurts where it won't power on, just clicks.
Then it'll be fine for a while.

I figured it'll just be a recap, but it's one of those super slim TVs, with long skinnySamwah caps.

What's a good source for replacement caps in this form-factor?

[tom66]

Re: Samsung 40C5000QF intermittent won't power on

I wouldn't immediately consider bad capacitors.
Have you checked the PSU voltages when it will and won't power up?

[smason]

Re: Samsung 40C5000QF intermittent won't power on

I wouldn't immediately consider bad capacitors.
Have you checked the PSU voltages when it will and won't power up?

No, I haven't done anything other than take the back off since it arrived.
Haven't even plugged it in.
House-full of people to feed today so won't get at it 'till Monday or Tuesday.

I assumed caps because the symptom is the same as the poster child for the Samsung bad caps class action lawsuit.

[tom66]

Re: Samsung 40C5000QF intermittent won't power on

But in those instances the capacitors almost always bulged; I'll bet yours haven't?

[retiredcaps]

Re: Samsung 40C5000QF intermittent won't power on

What's a good source for replacement caps in this form-factor?

I remember seeing some United Chemi-con long skinny caps in another picture and it looks like they have 2 possible series that might work?

http://www.chemi-con.co.jp/e/catalog/index.html

Check out KXJ and KHE.

[smason]

Re: Samsung 40C5000QF intermittent won't power on

But in those instances the capacitors almost always bulged; I'll bet yours haven't?

You'd win that bet, flat as pancakes.

[smason]

Re: Samsung 40C5000QF intermittent won't power on

I remember seeing some United Chemi-con long skinny caps in another picture and it looks like they have 2 possible series that might work?

http://www.chemi-con.co.jp/e/catalog/index.html

Check out KXJ and KHE.

Excellent, thanks!

[smason]

Re: Samsung 40C5000QF intermittent won't power on

OK, did some testing. Of course it behaves fine on the bench.
Got some more details from "the customer"he says it randomly powers itself off, then back on, and sometimes stays off and won't power on, just clicks.

Voltages on the power supply look good, maybe a hair high 5.3v 12.8v
Voltage regulators on the main boardhave good outputs well within spec.

For grins I measured the larger electrolytics on the power supply board. They're all in pairs in parallel, so not really too valid a test, but got readings that looked normal.

I'm tempted to give it back and tell him to bring it back to me when it fails and stays failed

[retiredcaps]

Re: Samsung 40C5000QF intermittent won't power on

I'm tempted to give it back and tell him to bring it back to me when it fails and stays failed

Intermittent problems are always difficult.

I have an ATX power supply (it was under warranty) that was intermittent. Now it is finally failed, but the form factor and tight spacing makes it virtually impossible to troubleshoot.

[smason]

Re: Samsung 40C5000QF intermittent won't power on

I'm tempted to give it back and tell him to bring it back to me when it fails and stays failed

Indeed that's what I'm doing. Giving it back to "the customer" and he'll let me know if/when it fails for good.

[Mt.Man]

Re: Samsung 40C5000QF intermittent won't power on

Look for cracked solder connections on all the small transformers. Common problem on these Samsung thin TV power boards. But you may have a main board thats acting up.