Phillips LCD TV repair

Thread Starter

wayneh

Joined Sep 9, 2010
17,153
A friend gave me an aging LCD TV and it worked for less than a year. Now the power-on LED comes on (or not, sometimes) but nothing much else happens. No sound or image of any kind. Can't pull up a menu. The power button sometimes flashes to give feedback that the remote is sending, but not always.

So today I opened it up and was disappointed to not see bulging capacitors or anything else obviously wrong. I've looked for the service manual and I suspect there is one but I can't find it. I found one that's "close": https://drive.google.com/file/d/1bTQ3kQiwx4soRmt68nw6y0KDQiShHt5h/view

Anyone have an idea? Should I bail out now?

Model: Philips 32HFL4461F/F7

IMG_3141.png
IMG_3140.png
 

Attachments

Last edited:

Thread Starter

wayneh

Joined Sep 9, 2010
17,153
Well dumb luck may have paid off. I couldn't see the power-on indicator (far lower left of wide shot above) with the unit face-down on the table, so I unscrewed it and turned the module over. To my surprise, the TV now seems to be fully working. At least I can pull up a menu. Maybe a bad connection at the ribbon cables?
 

Yaakov

Joined Jan 27, 2019
3,509
Look how hot the board is getting in the upper right hand quarter. Those caps might be drying out even if not bulging. I don't know if moving it around could change anything but, that is going to die.
 

Thread Starter

wayneh

Joined Sep 9, 2010
17,153
Look how hot the board is getting in the upper right hand quarter. Those caps might be drying out even if not bulging. I don't know if moving it around could change anything but, that is going to die.
Before the miraculous recovery, I was thinking about following my own typical advice and re-capping the thing. You think the discoloration is a sign of something abnormal? Maybe I'll focus on the caps in that area.
 

Yaakov

Joined Jan 27, 2019
3,509
Before the miraculous recovery, I was thinking about following my own typical advice and re-capping the thing. You think the discoloration is a sign of something abnormal? Maybe I'll focus on the caps in that area.
It's certainly a sign of a lot of heat, and that is never good for electrolytics. It's probably worth doing, though you could wait until it fails again.
 

Thread Starter

wayneh

Joined Sep 9, 2010
17,153
It's certainly a sign of a lot of heat, and that is never good for electrolytics. It's probably worth doing, though you could wait until it fails again.
It was showing a little flakiness before it failed. It would occasionally go dark while the audio continued, and then come back. So I may go ahead and swap them out while I have it open.

UPDATE - My luck ran out. It's struggling again. I think it had time to cool off while I horsed it around and took out that module. Once it heated up again, bad behavior has returned. I left it plugged in but powered off all night. This morning I noticed that the heatsink in that hot zone is warm, and so are the nearby caps. That can't be good. I'm also concerned by warmth of the shielded, tuner area. There's an LED glowing in there 24/7 and I suppose some power usage there is normal even when turned off. But enough to warm up the case? Seems suspicious. I guess I can remove the shield and look for bulgers but I think I'm getting in over my head.
 

Yaakov

Joined Jan 27, 2019
3,509
It was showing a little flakiness before it failed. It would occasionally go dark while the audio continued, and then come back. So I may go ahead and swap them out while I have it open.

UPDATE - My luck ran out. It's struggling again. I think it had time to cool off while I horsed it around and took out that module. Once it heated up again, bad behavior has returned. I left it plugged in but powered off all night. This morning I noticed that the heatsink in that hot zone is warm, and so are the nearby caps. That can't be good. I'm also concerned by warmth of the shielded, tuner area. There's an LED glowing in there 24/7 and I suppose some power usage there is normal even when turned off. But enough to warm up the case? Seems suspicious. I guess I can remove the shield and look for bulgers but I think I'm getting in over my head.
Power supply flakiness can cause all manner of odd behavior. If you replace the caps in the PS section, it might clear up.
 

Thread Starter

wayneh

Joined Sep 9, 2010
17,153
Probably time to bail.

Today I replaced the 5 larger caps in the upper right of the PS board. They were all 1,000µF. Four were 25V and one was 10V. I used 35V caps for all. Unfortunately there's a 50V, 47µF cap that I don't have a replacement for. That may be the one thing left to try.

No joy. So I removed the shield from the tuner, computer section. Nothing under there I feel like messing with! But I can tell one of the large (>1" square) chips is hot to the touch and another is warm. I can also see that the board appears to be trying to reboot itself repeatedly. A tiny green LED comes on. Then another comes on near the connector to the panel as the backlighting comes on. But a few seconds later all goes black and the process repeats. I didn't count it out but I think it gives up after 5? attempts and then powers down.

Seems a shame to junk the whole thing - the panel and backlighting work - but I don't think there's much choice.

The photo shows the 5 empty spots I replaced, and the 50V 47µF I didn't.
 

Attachments

Yaakov

Joined Jan 27, 2019
3,509
Probably time to bail.

Today I replaced the 5 larger caps in the upper right of the PS board. They were all 1,000µF. Four were 25V and one was 10V. I used 35V caps for all. Unfortunately there's a 50V, 47µF cap that I don't have a replacement for. That may be the one thing left to try.

No joy. So I removed the shield from the tuner, computer section. Nothing under there I feel like messing with! But I can tell one of the large (>1" square) chips is hot to the touch and another is warm. I can also see that the board appears to be trying to reboot itself repeatedly. A tiny green LED comes on. Then another comes on near the connector to the panel as the backlighting comes on. But a few seconds later all goes black and the process repeats. I didn't count it out but I think it gives up after 5? attempts and then powers down.

Seems a shame to junk the whole thing - the panel and backlighting work - but I don't think there's much choice.

The photo shows the 5 empty spots I replaced, and the 50V 47µF I didn't.
That's a shame. But the rebooting thing sure sounds like the PS is flaking.
 
Top