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A VGA monitor may be easier to repair than you think

cnx-software.com

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

#61

Post by grishka »

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?

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

#63

Post by bayindirh »

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 damaged parts myself.

The monitor came back alive for 30 seconds and then died again.

It had no leaky caps, no visible damage, nothing on the board.

Had to trash it.

So, YMMV.

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

#64

Post by Laforet »

yitchelle wrote: post #36
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…

> the market is literally invaded by rubbish quality capacitors, and swapping a bad quality one with another bad quality one guarantees it will fail again one day Actually, even a quality capacitor will fail eventually, just not as early as the fake ones. As you have mentioned about the heat, the capacitor will be exposed to it and will fail because of it.

I have replaced more capacitors in appliances than electronics. The fact that appliances runs on higher voltages and stop/starts frequently exacerbate the heat problem.

The 9 years old range hood in my kitchen is already had the start capacitor replaced twice. Whoever designed this unit decided to place the circuitry right in a hot spot, making sure that the capacitor will be gently toasted to death in a couple of years.

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

#66

Post by Laforet »

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.

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

#67

Post by mdip »

I think more than a few of us are familiar with the mess of bad capacitors that made their way into products throughout the early 00s. I still see this from time to time, but I remember the first time I encountered it -- I had purchased a $200 SageTV Media Streamer (v1) and it failed a few months out of warranty. I replaced it with a v2 and put the v1 in the basement.

Then Google bought SageTV[0] and they stopped producing software/products. Meanwhile, I wanted another TV hooked up. Taking apart the device revealed capacitors that -- even though I had been unfamiliar with the issues -- were obviously bad -- one had leaked all over itself, others were bulging.

I hit up ebay, repaired that, and thought about the growing pile of unreliable/broken hardware in a room that I had been putting off salvaging. That weekend, I repaired about ten LCD monitors -- caps in the PSU all around, one old plasma TV, 5 ATX power supplies and two NetGear 1Gbps switches. EVERY single one had varying degrees of damage. All but one power supply was functional again.

[0] The product was a TiVo for PCs and was among the best. Google purchased them as an acqui-hire and -- I think -- used portions of the software in their STBs for Fiber. They later released the code open source.

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

#68

Post by raxxorrax »

ksec wrote: post #11
jonatron wrote: post #3

Power supply caps fail so often that maybe they should be socketed?

The answer isn't socketed but high quality capacitor ( Solid or Tantalum etc ) . Swollen capacitor should really be a thing of the past. Unfortunately Capacitor is an area that is easiest to cut cost and has no immediate effect on the devices function and are hard to spot. Part of the reason why I switch over to Mac ~20 years ago. I dont want to spend time looking at every capacitor on a motherboard or to gather enou…

> Capacitor marketing on motherboard was a thing.

That is a thing? What do they advocate, the fine smell of rotten eggs when they die?

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

#69

Post by tailspin2019 »

sysadmindotfail wrote: post #43
zbuf wrote: post #23

I feel old; I came here for a guide to repair a "VGA monitor" and instead got a flat panel.

I am old. I did not even open the link until you mentioned it was an LCD. I was thinking: "Why would you repair a CRT?"

> I was thinking: "Why would you repair a CRT?"

Same here. And I didn't think I was that old...

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

#70

Post by fouc »

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?

does a bad capacitor always show damage visibly?
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