Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

A VGA monitor may be easier to repair than you think

cnx-software.com

Post reply on HN
Print view View original

81–90 of 128 posts

Re: A VGA monitor may be easier to repair than you think

#81

Post by BBC-vs-neolibs »

grishka wrote: post #61
squarefoot wrote: post #17

I've repaired several TVs and monitors, LED lamps, etc. just by replacing bad capacitors, and in a few cases some diodes too, so it's worth trying especially on electronics that would otherwise be thrown away. If you see a TV/monitor going off randomly or a LED lamp starts flashing, pretty sure there are one or more defective capacitors in there. Defective capacitors are a common plague in modern electronics, and the…

Huh. I have a Dell monitor that suddenly started showing these kind of smeared stripes instead of a proper picture. Took it apart, looked carefully at all the capacitors and other components on both boards, but none looked bad. Disconnecting and reconnecting the ribbon that goes to the LCD panel made no difference whatsoever. What could it possibly be?

Capacitors can be bad but look perfectly fine.

If there aren't many, one can just replace all of them.

Re: A VGA monitor may be easier to repair than you think

#82

Post by naikrovek »

squarefoot wrote: post #17

I've repaired several TVs and monitors, LED lamps, etc. just by replacing bad capacitors, and in a few cases some diodes too, so it's worth trying especially on electronics that would otherwise be thrown away. If you see a TV/monitor going off randomly or a LED lamp starts flashing, pretty sure there are one or more defective capacitors in there. Defective capacitors are a common plague in modern electronics, and the…

good caps go bad, too. service lifetime is a function of temperature and time. lower the operating temp by 10°C and you double the lifespan of the good name-brand capacitor, and probably quadruple the life of the crappy generic cap.

Re: A VGA monitor may be easier to repair than you think

#83

Post by goda90 »

I've got several broken electronics that I'd love to try to repair someday, but they don't have any screws and they are obscure enough to not have any tear-down guides to tell me if a heat gun would help. Cutting them open could just leave them unappealing to use, and thus I wasted my time.

Re: A VGA monitor may be easier to repair than you think

#85

Post by bayindirh »

Laforet wrote: post #66
bayindirh wrote: post #63

A had an awesome (for its time), Hyundai L90D+ monitor, and used it for ~8 years. One day it turned and stayed off, sent it to some local shop for repair, and the tech told me that he added another light control circuit and, my brightness had to be adjusted via an external control. He also said that two ICs damaged, and he cannot source any. I got pissed, found the parts, removed the other abomination and changed the…

The board had probably developed a short somewhere because one of those tiny ceramic SMD capacitors had failed which is very hard to tell just by looking at it. Or the PCB substrate may have degraded, allowing two traces to come into contact but this is less likely. The tech probably figured out that this was happening but was unable or unwilling to isolate the issue.

> The tech probably figured out that this was happening but was unable or unwilling to isolate the issue.

I suspect. It was just a run of the mill repair shop. If he had found it, it would have warned me when I told him about my future intentions.

Re: A VGA monitor may be easier to repair than you think

#86

Post by hermitdev »

mikewarot wrote: post #57

Since the title specified a resolution, I assumed a VGA CRT with a DB15 connector. (Not an MDA, CGA or EGA) I was all set to warn you kids about the dangers of CRTs, high voltage, Xrays, and of course the implosion if you break the neck of the tube... and instead got bad capacitors on LCD displays. Regardless of what the safety standards say, you should always remove power, and short any capacitors with a screwdriver…

I also immediately had flash-backs to opening up an old CRT 13" TV that was going flaky (the sort of flaky where sometimes percussive maintenance worked). Being an electrical engineering student at the time, I thought I could handle it. I knew about the high voltage, I knew about the retained charged of the capacitors, etc, etc. What I wasn't prepared for was just how poorly shielded this thing was once I got it opened.

I shocked myself almost immediately as I was doing basic examination. I hadn't even gotten to probing for shorts or broken connections. Thankfully, the shock wasn't bad, more startling than anything (I remember it being somewhat like brushing up against an electric fence). I was wearing a grounding strap on the arm of the hand where I got shocked. Not sure how much/if that helped any.

That was enough for me to determine I wasn't qualified to work on it. I reattached the case and lived with its flakiness for a few years longer until it was replaced with an LCD.

Re: A VGA monitor may be easier to repair than you think

#87

Post by josefresco »

kichimi wrote: post #10
blueflow wrote: post #4

Earlier quoted context omitted.

"modern" does not imply "better" anymore, for at least a decade now. Think of SmartTV, microwaves, or every kind of consumer electronics in general.

I do think you should open your mind a bit. Smart TVs are pretty terrific, I can just cast whatever I want across the room and bam, it's on the TV. Friends can come over and share the input. I can lay in bed with nothing but a remote and browse my plex library. I used to go along this line of thinking, and had a "dumb" TV for a long time. I would spend hundreds of hours trying to get a PC/xbmc/kodi setup with a remot…

Dumb TV + Streaming stick is the way to go. Bundling your TV (hardware) with your smart TV (software) is a recipe for disappointment and frustration 2-3 years down the road when the tech evolved and your TV manufacturer has lost interest in supporting your model (looking at you LG)

Re: A VGA monitor may be easier to repair than you think

#88

Post by BizarroLand »

naikrovek wrote: post #82
squarefoot wrote: post #17

I've repaired several TVs and monitors, LED lamps, etc. just by replacing bad capacitors, and in a few cases some diodes too, so it's worth trying especially on electronics that would otherwise be thrown away. If you see a TV/monitor going off randomly or a LED lamp starts flashing, pretty sure there are one or more defective capacitors in there. Defective capacitors are a common plague in modern electronics, and the…

good caps go bad, too. service lifetime is a function of temperature and time. lower the operating temp by 10°C and you double the lifespan of the good name-brand capacitor, and probably quadruple the life of the crappy generic cap.

Then again, if the item you are repairing is 4 years old or more, then the original caps have enough life span to justify using same quality replacements. Sure, you might only be saving 30 cents on an individual item (not counting shipping), but if its what you have on hand there's not really a downside.

Re: A VGA monitor may be easier to repair than you think

#89

Post by kasabali »

grishka wrote: post #61
squarefoot wrote: post #17

I've repaired several TVs and monitors, LED lamps, etc. just by replacing bad capacitors, and in a few cases some diodes too, so it's worth trying especially on electronics that would otherwise be thrown away. If you see a TV/monitor going off randomly or a LED lamp starts flashing, pretty sure there are one or more defective capacitors in there. Defective capacitors are a common plague in modern electronics, and the…

Huh. I have a Dell monitor that suddenly started showing these kind of smeared stripes instead of a proper picture. Took it apart, looked carefully at all the capacitors and other components on both boards, but none looked bad. Disconnecting and reconnecting the ribbon that goes to the LCD panel made no difference whatsoever. What could it possibly be?

If there are vertical lines most likely Cof or T-Con board failure. Unfortunately it isn't an easy repair. (Although some YouTube videos show you can work around some minor cof failures by isolating broken lines with a tape)

Re: A VGA monitor may be easier to repair than you think

#90

Post by BatFastard »

grishka wrote: post #61
squarefoot wrote: post #17

I've repaired several TVs and monitors, LED lamps, etc. just by replacing bad capacitors, and in a few cases some diodes too, so it's worth trying especially on electronics that would otherwise be thrown away. If you see a TV/monitor going off randomly or a LED lamp starts flashing, pretty sure there are one or more defective capacitors in there. Defective capacitors are a common plague in modern electronics, and the…

Huh. I have a Dell monitor that suddenly started showing these kind of smeared stripes instead of a proper picture. Took it apart, looked carefully at all the capacitors and other components on both boards, but none looked bad. Disconnecting and reconnecting the ribbon that goes to the LCD panel made no difference whatsoever. What could it possibly be?

Interestingly I have 5 Dell monitors, and 10 Samsungs that are 15 years old. Dells are all still running strong. While the Samsungs have needed replacement Caps, and their DVI ports have flaked out. I did find that if I use the VGA port they will work well though, strange...
Post reply on HN