Samsung LN46A550P3FXZA Squealing, clicking on and off

[budm]

Re: Samsung LN46A550P3FXZA Squealing, clicking on and off

I use PANASONIC FM/FR series from DIGIKEY for al my repair works.
You need to look the spec of what you have.

[captainKKK]

Re: Samsung LN46A550P3FXZA Squealing, clicking on and off

I am NOT an electronics trained anything, but I have always been fascinated and try to repair electronic stuff. I fix computers for a living but not at component level, unless I REALLY want it working. That said, I tried everything I knew before I found this thrread by mistake......lots of shop jimmy this and that, youtube watching wasted and was within 2 clicks on buying a new 4K TV. Then OMG I read this for my Samsung LN37A550 that was 7 days dead and headed into the trash and all I did was resolder the R107, the IC101 and the R124 and POOF....just like new. All the auto booting rebooting with weird vertical lines and colors, then the loud squealing, rebooting and repeating STOPPED. FYI you can get the repair manuals and find the secret FACTORY codes to use from the remote to Factory reset this thing, which I did prior to doing this stuff here. THANKS GUYS......I guess I will get a couple of extra Switching Voltage Regulators 3A 27V 385kHz Step-Down Converters and the caps, just for backup. SWEET....

[captainKKK]

Re: Samsung LN46A550P3FXZA Squealing, clicking on and off

Either one of these two for NEC-TOKIN caps.
You can temporary solder 100uF 10V low ESR in parallel with the C102 to see if it will solve the problem, mines did.

Thanks BUDM, you the man, 2nd day your fix is working for me without a glitch, all I did was resolder the caps and the top regulator.

[rccrasher65]

Re: Samsung LN46A550P3FXZA Squealing, clicking on and off

Oh, and the customer's that I have on the bench right now is a PN50A500 plasma.

This issue with the high pitch squeeling, was fixed years ago, on here with C102, seems nobody goes through old threads. this same Samsung model PN50A500 was the one in the thread.

[captainKKK]

Re: Samsung LN46A550P3FXZA Squealing, clicking on and off

Thanks BUDM, you the man, 2nd day your fix is working for me without a glitch, all I did was resolder the caps and the top regulator.

PARTS:

https://www.eciaauthorized.com/en/search/MP2363DN

[captainKKK]

Re: Samsung LN46A550P3FXZA Squealing, clicking on and off

I am NOT an electronics trained anything, but I have always been fascinated and try to repair electronic stuff. I fix computers for a living but not at component level, unless I REALLY want it working. That said, I tried everything I knew before I found this thrread by mistake......lots of shop jimmy this and that, youtube watching wasted and was within 2 clicks on buying a new 4K TV. Then OMG I read this for my Samsung LN37A550 that was 7 days dead and headed into the trash and all I did was resolder the R107, the IC101 and the R124 and POOF....just like new. All the auto booting rebooting with weird vertical lines and colors, then the loud squealing, rebooting and repeating STOPPED. FYI you can get the repair manuals and find the secret FACTORY codes to use from the remote to Factory reset this thing, which I did prior to doing this stuff here. THANKS GUYS......I guess I will get a couple of extra Switching Voltage Regulators 3A 27V 385kHz Step-Down Converters and the caps, just for backup. SWEET....

UPDATE: After reassembly, I temperature gun on C132 area showed 190 degrees F, this is probably the cause of this cold solder issues on both sides of the main board. My computer CPU does not run this hot....POOR design.

[captainKKK]

Re: Samsung LN46A550P3FXZA Squealing, clicking on and off

UPDATE: After reassembly, I temperature gun on C132 area showed 190 degrees F, this is probably the cause of this cold solder issues on both sides of the main board. My computer CPU does not run this hot....POOR design.

Keep in mind, I am NOT an electronics guy (unlike BUDM, who is now my idol). After replacing the main board post re-soldering, it seems to me the "brains" CPU take some time to "realize" its been fixed and may take time to boot/stabilize.......ie 60 seconds for me. After this first extension of boot, it went right back to normal, and remains so. So, for us un-educated guys doing this, DO NOT be disappointed when turning on does not result immediate satisfaction........and you trash it because you think you ruined it.....be patient......

[taligent]

Re: Samsung LN46A550P3FXZA Squealing, clicking on and off

I came across an LN40A550 that failed to power on and only showed a blinking red light. The power supply capacitors had been previously replaced and measured fine out of circuit for capacitance, ESR, and Vloss as seen by an AVR transistor tester.

On the main board, the bottom side C102 capacitor showed correct capacitance near 47uF but ESR was bad at 0.72 ohms - according to the NEC data sheet, this should be no more than 0.1 ohms. The top side C131 measured good with capacitance near 47uF and ESR at 0.01ohms.

I removed C102 completely and moved the good C131 capacitor to C102, and also installed a parallel 150uF/10v capacitor for a little extra insurance (nothing special about the value, it was just the lowest ESR cap I had in spare parts around the original 47uF value). I installed a low ESR electrolytic in C131 and the set powered on!

Thanks budm for the info on this failure! Otherwise this TV would have been scrapped for parts as it's old enough that it wouldn't have been worth the time to trace the fault. It's a bit dim (service menu shows 33990 hours) so it'll be consigned to a dark room, but at least it's not heading to recycling.

[captainKKK]

Re: Samsung LN46A550P3FXZA Squealing, clicking on and off

UPDATE: 90 days later and my Samsung LN37A550 is still working flawlessly. Thanks BUDM. If you can figure it, why can't Samsung build it more durable?

[delaware74b]

Re: Samsung LN46A550P3FXZA Squealing, clicking on and off

Budm, thanks for the insight on this model main board. A friend of mine has a LN46A540P2FXZA with the same issue of cycling, green banding and squealing. I replaced the C102 with a Nichicon PM 100@16volts and it went away. I am also going to replace C131 as a preventive measure.