Philips 32TA1000 LCD Colour TV repair - Page 1
Forum section: electronics / repair

author: 0b01010011
author_rank: Regular Contributor
timestamp: November 09, 2014, 03:33:25 am
content: Have been a long time lurker of the forum and follower of EEVBlog but thought I would join up mainly to document this for others.My 8 year old Philips 32TA1000 LCD TV recently started behaving strangely - either resetting and then failing to display a picture until powered on/off, or displaying rainbow snow, or corrupting the colour mapping, so green was red, etc.This was quite intermittent for a while, and led to me changing cables etc., to no avail. It then started happening the same time other devices came on, so when the fridge compressor kicked in the TV would trigger, likewise with the subwoofer coming on.This led me to think it was a capacitor issue, so I opened it up to see if I could see any dodgy caps, however they all looked OK to me. But I decided to order some in and give it a go - I ordered a new set (apart from the tuner decoupling and audio stages, both of which I don't use) of through-hole Electrolytics from Farnell, all low ESR Rubycon, Nichicon and Panasonics to replace the crappy Capxon and Elite ones Philips put in there.I fitted them yesterday and all has been fine so far! Probably wouldn't have had to courage to do it if it wasn't for some of Dave's recapping videos and seeing how it worked for him, as this is our main TV.Was a good excuse to order $45 worth of stuff from Farnell for the free postage, after seeking wife approval of course.

author: retiredcaps
author_rank: Super Contributor
timestamp: November 09, 2014, 03:55:07 am
content: I have seen this power board on badcaps.net a lot and those Capxon capacitors are usually at fault on both boards.

author: 0b01010011
author_rank: Regular Contributor
timestamp: November 09, 2014, 04:13:49 am
content: Yes I suspected the issue was in the power board, maybe even the main 120uf primary reservoir capacitor given the issues when other larger-inrush devices came on, but this TV is such a bitch to open up I did them all, since I already had to disassemble and reassemble it once to get the cap values.

author: Vito_R
author_rank: Regular Contributor
timestamp: November 09, 2014, 04:23:24 am
content: We usually call those caps CrapX. I don't even bother testing them anymore, just change them with nichicons every time I see them. There are other problem caps you'll see often like Samxon, Chengx, and a few other chinese caps that fail often. Just recap the PS board and you will extend the life of your tv for many years even if those caps are not even acting up yet.

author: TheBay
author_rank: Unknown
timestamp: November 09, 2014, 04:26:57 pm
content: Quote from: Vito_R on November 09, 2014, 04:23:24 amCrapX love it!

author: 0b01010011
author_rank: Regular Contributor
timestamp: November 10, 2014, 02:09:19 am
content: Bad news, the same rainbow snow and reset-type issue happened again today, when the subwoofer clicked on. It seems to happen less often though otherwise.The DVR I use with the TV is about the same age (8 years) but the caps looked OK in that a few weeks ago when initially suspected the DVR may be at fault.Anyone have any idea what it could be - I could perhaps re-cap the DVR as I have some left over from recapping the TV.For reference my system consists of:Philips 32TA1000 TV (connected via a DVI to HDMI cable to...)Marantz NR-1403 AVRLG LST-5403P DVR (connected to AVR via HDMI)Boston Soundware XS subwoofer (connected to AVR via phono sub connection)It's the fact that this usually happens when the sub kicks in that leads me to think this is a capacitor age issue. I could be totally wrong though of course!

author: Vito_R
author_rank: Regular Contributor
timestamp: November 10, 2014, 02:26:31 am
content: Is this issue only happening when the DVR is used ?? Did you try disconnecting all your components and just feeding the TV HDMI from another set top box and see it the issue still occurs?

author: Vito_R
author_rank: Regular Contributor
timestamp: November 10, 2014, 02:31:21 am
content: The other thing I could think of is you said it clicks off when the subwoofer comes on therefore producing strong bass and vibration. Is the sub near the TV? if the vibrations are strong enough I'm thinking it could be affecting some loose ribbon cables in the TV on the T-CON board for example.

author: Vito_R
author_rank: Regular Contributor
timestamp: November 10, 2014, 02:38:48 am
content: Reading your 1st post again I just thought it could also be some kind of voltage drop or surge on the AC mains triggering your power supply to fail. I would setup a test meter on the DC outputs of the power supply while it is in operation and record what happens when you trigger this with the surround sound sub on. See if the power supply outputs drop out or fluctuate. If you have a fluke meter for example use the min max mode and record. Also check your AC mains input into the power supply on min max mode and see if there are any voltage sags or fluctuations. Be very careful the heat sinks are HOT as in energized. Do Not touch them or work behind the TV when mains are on. Use an isolation transformer if you have one and be very careful and only make your connections before you plug into the mains.

author: 0b01010011
author_rank: Regular Contributor
timestamp: November 10, 2014, 02:46:31 am
content: Vito_R - haven't tried connecting the DVR directly to the TV via HDMI, everything has been through the AVR, apart from the pre-AVR days when it was connected using component video rather than HDMI.What leads me to think this isn't DVR related is that it also happened with other HDMI sources such as a Raspberry Pi and also a DVD player.I'll try the direct DVR-HDMI connection tonight.As for the sub I don't think it would be strong bass/vibration as this even happens at low volumes - for example this morning I had the news on - this wasn't enough to trigger the sub coming on until the theme music came on at the end of the bulletin - this was enough to trigger it to come on (i.e. from standby to powered on) and as soon as I heard the relay click the TV blanked out.I am not sure how other subs work, but mine has a standby circuit that senses the audio level, then when it's a certain level triggers a relay to turn on the PSU/amplifier inside the sub. Similarly when the audio level is low for a while (2-3 mins) it turns the relay off to turn off the PSU/amplifier.

author: 0b01010011
author_rank: Regular Contributor
timestamp: November 10, 2014, 02:50:11 am
content: Yes that's a good idea I'll set up the meter tonight once the kid has gone to bed and take some min-max recordings - then if I get nowhere there I'll try on the DC bus.I do have a meter with min-max (not a Fluke sadly, but not a $10 Jaycar special either). I sadly destroyed my Fluke with a ceiling fan the other day trying to untangle the probe wires.

author: Vito_R
author_rank: Regular Contributor
timestamp: November 10, 2014, 02:50:53 am
content: You mentioned above on your first post that it also happened when the compressor on your fridge came on? Is that still happening?

author: Vito_R
author_rank: Regular Contributor
timestamp: November 10, 2014, 03:00:00 am
content: Quote from: 0b01010011 on November 10, 2014, 02:50:11 amMy condolences for your Fluke. She was a great meter.

author: 0b01010011
author_rank: Regular Contributor
timestamp: November 10, 2014, 03:41:34 am
content: Thank you, I cursed myself for days afterwards for buying a fan with metal blades. If only they displayed an LCD display smash rating on them I would have settled for plastic blades.

author: Vito_R
author_rank: Regular Contributor
timestamp: November 10, 2014, 03:47:36 am
content: Quote from: 0b01010011 on November 10, 2014, 03:41:34 amSounds like you should help Dave out with his next Multimeter torture test. Maybe you can finish destroying that Fluke 28 he wasn't able to crack.

author: 0b01010011
author_rank: Regular Contributor
timestamp: November 10, 2014, 11:30:19 am
content: Well I tried direct connection between TV and DVR and that went OK for the time I tried (about an hour). I'll have to try for longer though I think to get any solid conclusions there.One thing I did notice though was that the DVR and sub were plugged into a 2-way mains adaptor - this was making very poor contact I think, certainly from the crackles that happened from just adjusting the position of the plugs (not even pulling them out), so perhaps this was to blame.I've removed the 2-way adaptor for now and the sub just plugs directly into the wall socket.As for the mains voltage, I did some min-max measurements but all came out with the voltage completely solid - min of 241 and max of 246 volts, power cycling the sub at least 15 times during that measurement time to try and any effect from the inrush. I think either the inrush must be far less than I thought it may be, or could have been that once charged the PSU reservoir cap stayed charged despite me giving a minute or so to discharge between power cycles.Anyway at least with the adaptor out of circuit that may help. If not I will forgo digital connection via HDMI-DVI to the TV and just resort to component video, since the AVR does have provision for this.

author: Vito_R
author_rank: Regular Contributor
timestamp: November 11, 2014, 12:21:33 am
content: Hopefully it was just that poor quality 2-way adapter it was plugged to. Keep testing long term and let us know. If the issue reoccurs consider the following: If your DVR's HDMI output and video from other set top boxes were all running through your AVR receiver it could simply be a defective. However, you mentioned in your first post that this also occurred when the compressor in your fridge kicked in which leads me to believe it is still some mains power issue. Is that still happening when the compressor comes on? Maybe it was affecting the AVR receiver causing it to cut out or cause an issue with the HDMI output. Keep testing it with all your devices plugged directly into your tv without the AVR connected to anything. What you can do later is plug some audio into your AVR receiver and no other devices running through it and get the subs working to see if that affects or causes the TV to cutout. If after all that you see the issue reoccur again try monitoring the DC bus on the TV PS with min max on your meter. This should allow you to isolate which device is the culprit. Good luck

author: Macbeth
author_rank: Super Contributor
timestamp: November 11, 2014, 12:52:50 am
content: CrapXcon. At least they label them so you know they should all be replaced. It's the fake Panasonics, Nichicon, etc. that can throw you if they haven't vented. I need a decent in-circuit ESR meter. Mind you PSU's are usually only double sided boards so it's not hard to just desolder and lift a leg to check them. Meh.

author: Vito_R
author_rank: Regular Contributor
timestamp: November 11, 2014, 01:08:24 am
content: Yes I agree the fake caps can be a problem too thats why I always buy my stock from the big distributors like Digikey or Mouser to lessen the chances of that ever happening. I've also seen a lot of caps fail without any signs of venting or leaking that's why a good ESR meter is always recommended. The exception is when I see CrapX I just Shhhcrap themmmm.

author: Vito_R
author_rank: Regular Contributor
timestamp: November 11, 2014, 01:15:20 am
content: I can recommend the ATLAS ESR meter made in the UK. I love it. But know it tests caps 0.5uf and above. The bob parker blue ESR meters are also great too.

author: 0b01010011
author_rank: Regular Contributor
timestamp: November 11, 2014, 02:48:13 am
content: Yeah with the fake caps that's why I went to Farnell to get the new ones for the TV - ebay and the local JayCar store were cheaper, but almost all were no-name or unknown (to me) brand caps when I wanted to just do it right the first time. Of course if this was a scummy breadboard type project I wouldn't care as much.I agree it certainly points to the AVR as a culprit, at least until I can do some further testing. Like you said it just seems so PSU related when it's happening at switch-on times for other devices. The AVR is quite new, so I am wondering as well if it could be an HDMI incompatibility between the TV (which only has a DVI port) and the AVR.As you suggest I will try and rig it up so that the AVR can be used for audio and the TV just has a direct connection to the DVR.

author: 0b01010011
author_rank: Regular Contributor
timestamp: November 11, 2014, 02:50:41 am
content: Quote from: Vito_R on November 11, 2014, 01:15:20 amAn ESR or perhaps an LCR meter is on the list of 'test equipment to buy'.. may have to 'accidentally' add one to my basket next time I am on Farnell or RS online.

author: Vito_R
author_rank: Regular Contributor
timestamp: November 11, 2014, 03:04:17 am
content: Quote from: 0b01010011 on November 11, 2014, 02:50:41 amJust keep that new LCR meter away from your fan this time and you should be ok