Samsung LN32C540 Standby Light Only

[aaronwt6]

Just picked this up yesterday evening. When plugged in, the standby light comes on but the unit will not respond to the remote or the power button the touch pad on the front.

I've checked voltages coming out of the power supply and I have 5V present at only the A5V pin. I figure that's the standby of course. I've also checked the wires going from the control board to the touch sensor / remote sensor board and find it strange that I have 3.3V at about 7 of the 10 lines there. Maybe that's normal.

I can unplug the control board wires and still get no backlight. I had a similar model a while back (46") and that would automatically turn them on per some instructions I found on here. I can also jump between A5V and PS-ON on the power supply and nothing happens.

Based on the fact that jumping those two points gives me no change in the output on the supply, I'm thinking that's got to be the problem. Any opinions on it would be greatly appreciated.

Thanks,

Aaron

[kc8adu]

Re: Samsung LN32C540 Standby Light Only

if you pull up pson and nothing happens start there.
and someone used nichicon vz to recap?
not going to cause this problem but vz are not low esr.ky would be more like it.

[aaronwt6]

Re: Samsung LN32C540 Standby Light Only

Hmmm. I didn't notice it had been worked on before. Definitely suspicious of the supply then.

Can anyone confirm that the backlight should come on with the control board disconnected on this model?

Thanks again,

Aaron

[aaronwt6]

Re: Samsung LN32C540 Standby Light Only

Found this thread so definitely has to be the power supply. I don't get 24V out to the inverter board with the control cable unplugged.

[newtothis]

Re: Samsung LN32C540 Standby Light Only

Can you post a pic of the reverse of the PSU?

Also have you checked SMD fuses? Be labelled like Fxxx

[aaronwt6]

Re: Samsung LN32C540 Standby Light Only

Ok. So this was definitely worked on before which doesn't make me feel very good. No telling if it was repaired or if the work was done because of the problem and then it never functioned.

Someone did a horrible job with the solder too.

[aaronwt6]

Re: Samsung LN32C540 Standby Light Only

Unsure on the fuses. I can't seem to locate any but maybe I just don't know what I'm looking for.

Cheapest PS I see online is around $50. If I saw one for $30 I'd go for it for sure after looking at the 'repair' on this one.

[newtothis]

Re: Samsung LN32C540 Standby Light Only

Unsure on the fuses. I can't seem to locate any but maybe I just don't know what I'm looking for.

Cheapest PS I see online is around $50. If I saw one for $30 I'd go for it for sure after looking at the 'repair' on this one.

I'll skim over the pics and locate for you

[newtothis]

Re: Samsung LN32C540 Standby Light Only

Ok I cant clearly see the labels for the components... but before anything... that soldering.... looks as if at least one of those joints is cold!

I am assumeing that if those caps are wobbled the joints wobble too?, looks like the second pic shows a bad joint... it looks as if it is riding a few mm above the pad

[aaronwt6]

Re: Samsung LN32C540 Standby Light Only

This may be a bit better out in the sunlight. I really don't think any of the solder joints are cold but they do look bad. I may touch them up later just in case. Seems the person didn't use a hot enough iron.

I have to take my son to the park for a bit to play but I'll check back in later today.

Thanks for the help,

Aaron

[newtothis]

Re: Samsung LN32C540 Standby Light Only

yes before anything else I would remove the caps, clean the pads and resolder and see what happens, Can work from there then.

[aaronwt6]

Re: Samsung LN32C540 Standby Light Only

Will do. I'll get that done this afternoon and report back later today. Fingers crossed but I sure do hate working behind someone, especially when their work looks like this.

[newtothis]

Re: Samsung LN32C540 Standby Light Only

LOL! Something i learnt was that anything can be repaired, just depends how much time you want to put behind it (any money of course)

[aaronwt6]

Re: Samsung LN32C540 Standby Light Only

I hear ya. Time turns in to $30-$50 quick though. Back later with the report. I really should just change the caps again to something better but hate to do that either if I don't know if the supply works.

[newtothis]

Re: Samsung LN32C540 Standby Light Only

My guess is someone read up on common PSU prolems and found out about caps... opened her up and spotted some bulging caps... Decided to replace them with little or no soldering experience and bodged it quite badly.... Created poor contact and never fixed the issue and let the set go... From where those shoddy caps are on the circuit i am willing to bet my life that it is those caps preventing that set from powering up

[aaronwt6]

Re: Samsung LN32C540 Standby Light Only

Allright. Cleaned up all the solder joints and still no go. And I can attest that they are now well done. :-) Still wondering if the thing even worked before the attempted 'repair'. I need to just buy some packages of common capacitors so I have some sitting here for cases like this.

Another thing I'm questioning is if they are even the correct capacitors given the quality of the work that was done.

[newtothis]

Re: Samsung LN32C540 Standby Light Only

do you have the board number off the PSU?

[aaronwt6]

Re: Samsung LN32C540 Standby Light Only

BN44-00338B

And wow, is this ever an expensive board. I can find the 'A' version for under $30 but it's not the same.

Oh, and I just messaged the person I bought it from and the problem occurred prior to the re-cap. That was done as an attempt to fix it by a friend of the seller and the problem persisted afterward.

So, to me they have now added an additional variable to the mix.

[tom66]

Re: Samsung LN32C540 Standby Light Only

Well, at least they look to have used good caps.

You may be able to use the A variant if:
a) the connectors/inputs are largely the same (such it will fit in the case and connect properly); and
b) power ratings are the same (32 inch vs 32 inch, not 32 inch in 37 inch set) (power boards only); and
c) the set lets you change the panel model from the menu (most Samsung sets do) (main boards only)

In fact Samsung main boards are pretty good for interchangeability.

[aaronwt6]

Re: Samsung LN32C540 Standby Light Only

Well, I of course can't check the menu to verify but the version A supply certainly looks to have the same plugs, and locations.