Dynex 32" TV - Page 1
Forum section: electronics / repair

author: injb
author_rank: Regular Contributor
timestamp: February 13, 2019, 02:25:41 pm
content: I have a Dynex 32" LCD tv that I haven't turned on for about 2 or 3 years. Yesterday I plugged it in and tried to turn it on - the red LED is on, but it won't come out of standby. It's the same with either the remote or the buttons on the side.Any suggestions? It definitely worked last time I tried it, and it's just been sitting with no power since then. Are there any tricks I can try before tearing into it? Thanks!

author: shakalnokturn
author_rank: Super Contributor
timestamp: February 13, 2019, 10:28:21 pm
content: It's quite funny the number of things that break down "just sitting there".In your case I would have expected the side buttons to have developed some oxidation on the contacts as they often do over time, but then it's not responding to the remote either...In the worst case the side keys are oxided and you stored the remote with batteries that leaked so that isn't working either. Check the remote is actually emitting light with a smartphone/camera.Next options are that the main supply electrolytics were on the edge when you stored it, time did the rest, or some insect got in and nested in a critical spot on the PSU.

author: injb
author_rank: Regular Contributor
timestamp: February 14, 2019, 12:52:41 am
content: Quote from: shakalnokturn on February 13, 2019, 10:28:21 pmThanks. The funny thing is, I took the back off to have a look, and since I couldn't see anything obviously wrong with any components, I tried powering it on, and lo and behold, it worked! I put it back together and it's been working fine since then, with either the button on the side or the remote. I must have disturbed some magic dust or something.Great tip for checking the remote with the smartphone...I hadn't thought of that but it works nicely.

author: james_s
author_rank: Super Contributor
timestamp: February 14, 2019, 05:13:37 am
content: Was it stored somewhere cold? This may not be the issue yours had, but when electrolytic capacitors start to fail they are worse when cold, the ESR drops as they warm up. This is the reason so many devices will work fine then you turn them off and the next time you try to use them they won't turn on. Capacitors may bulge or leak when they get really bad but it's quite common that they look perfectly fine.

author: GreyWoolfe
author_rank: Unknown
timestamp: February 14, 2019, 02:49:55 pm
content: I have a Dynex 32" that my son gave me instead of putting it on the curb. It has no sound but works as a decent computer monitor. The reality of it is that if it stopped working, I wouldn't waste time trying to repair it unless it was obvious bad caps. It is a low quality product, but for the price I got it for, it serves my needs.

author: injb
author_rank: Regular Contributor
timestamp: February 14, 2019, 03:16:24 pm
content: Quote from: james_s on February 14, 2019, 05:13:37 amNo, it was stored in the living room of my apartment, so normal temps. It just sat there for a few years, unplugged and untouched. When I was hooking it up, the base had become stuck to the glass table it sits on because it hadn't been moved in so long!Quote from: GreyWoolfe on February 14, 2019, 02:49:55 pmFunny, I got mine for free too. And I feel the same way - if I didn't find anything obviously wrong, I was going to trash it and buy another one for $100 or so. But it was annoying because I never use a TV anyway, and I only wanted it to set up a raspberry pi I just got. Once I have it set up and networked, I don't need a monitor any more because I can use ssh. So I wasn't looking forward to buying a new TV for 30 minutes of use!

author: Doctorandus_P
author_rank: Super Contributor
timestamp: February 15, 2019, 12:45:08 pm
content: Electrolytic Capacitors may start leaking if not used for an extended period of time, because the very thin insulating oxide layer dissolves or get broken down.When applying power again the oxide layer starts reforming.When the leakage is very bad then this may cause so much internal heating that the capacitors explode / burst open, and to preven perferctly salvagable capacitors from destroying themselves there are tutorials for "reforming electrolytic capacitors" on the 'net.A leaking capacitor may have thrown some voltage off somewhere in the TV, but it's just a guess.

author: james_s
author_rank: Super Contributor
timestamp: February 15, 2019, 05:37:27 pm
content: I've re-formed capacitors in antique gear a few times but as far as I can tell that doesn't really apply to modern (as in under 40-50 years old) gear. Modern gear that has switchmode power supplies can't have the voltage brought up slowly, if the PSU doesn't self destruct it will normally not start up until the voltage crosses the undervoltage threshold.