Samsung LE32D400E1W power cycle/clicking + blinking

[goldfinch]

Hello, for a few years now this tv has had an intermittent fault. At random times it switches off and begins power cycling - the samsung logo appears, and I can hear the relay click, as described in other threads. If I leave it for a while it will often stop cycling in this way and sit with the LED blinking. It alternates between these two states at random intervals.

For some reason, punching the TV in the lower right corner usually resolves the issue for a while! This can fix it from anywhere between 2 minutes to several hours. This even resolved the issue for around 6 months with no trouble, though recently it has reemerged.

I haven't tried repairing a TV before, but my first thought was dodgy capacitors, so I checked and couldn't see any obvious issues. The fact that giving it a smack repairs it would suggest a bad solder joint or similar, but I don't know if it could affect components in other ways. From reading around the forums these symptoms could tally with a bad voltage regulator?

Unfortunately I can't provide pictures right now but will do soon. Thanks in advance for any advice.

[CapLeaker]

Re: Samsung LE32D400E1W power cycle/clicking + blinking

First thing I'd do is taking that PSU out and inspect the solder connection on every device that is mounted on a heat sink and all the transformers.

[goldfinch]

Re: Samsung LE32D400E1W power cycle/clicking + blinking

All the joints seem fine on visual inspection. Will take some (low quality, unfortunately) photos soon.

[CapLeaker]

Re: Samsung LE32D400E1W power cycle/clicking + blinking

What happens if you unplug the main board from the PSU (leave the backlights connected and) plug the TV in. The PSU should turn on (if it has a pull up resistor) and the back lights should be on too. Let it run an see what it does.

[goldfinch]

Re: Samsung LE32D400E1W power cycle/clicking + blinking

OK, just plugged it in like that and off the bat it seems fine - backlight is on constantly. Going to leave it running for a couple of hours and see if it stays that way.

Edit:
After a while I decided to plug the main board back in, wait for the power cycling to start, and then unplug it. Once the main board was back in I left it sitting, but it didn't start power cycling after 30 mins or so (as I would expect). I've never actually tested it without something plugged in to HDMI, so I've plugged a device in now and seeing what happens. Possibly it could be exacerbated by heat generated from actually decoding the HDMI signal, or I guess the stress on the connector from the cable being plugged in?

[goldfinch]

Re: Samsung LE32D400E1W power cycle/clicking + blinking

I've left it running for around five hours and it hasn't power cycled. 24 hours ago this TV was completely inoperable, but when I want it to break it won't! I will return to this thread once it stops working again.