22" monitor GNR TS2200WA - info?

I've prized the case off and got sight of the two boards; one power and one logic. Both well provided with component annotations, even for the jumpers, but of course I don't have a schematic. Boards are connected by a cable that, it says, supplies +5V and has one sense "ADJ" line and one "On/Off" line. Quite like a PC or no doubt lots of other appliances which have a low-power standby state. The power supply is marked that it supplies +5V, and "optionally" +24V, +12V and -8V. Measuring, the +5V started at ~3V and worked up to a rather wobbly 5V. Must stick a 'scope on the wobbles to see if I can spot a pattern. The "ADJ" line also varied ~2V / ~3V. But clicking the power switch made no difference to the +0.1V on the "On/Off" line.

Mike.

Do you have an ESR meter? Whether or not, I would automatically suspect on e or more bad electrolytic capacitors. If any have swollen cases, they are surely bad. Even if there is nothing visible, I would replace all of the electrolytics in the power supply.

Did you see this youtube about the monitor ?

I think I would start out just replacing the electrolytic capacitors on the power board.

Many switching supplies seem to have blown capacitors. I have repaired several items around my house by replacing capacitors.

One give away for me is to take the heat gun of my hot air rework station and playing it around one or two capacitors at a time. If the set starts working or manking a big change I replace them.

Stuff a heat gun into the power supply and get it nice and toasty. If it powers up, recap the electros.

The heat gun I have is a paint stripper. I use it a lot to shrink heat- shrink tubing but am reluctant to play it on electronics. And I cannot find the non-contact thermometer I was sure I had.

Viewing the youtube video I think was meant, I see the same capacitors have bulges in my power supply. So though I cannot pop down to my local Maplin (like the youtuber) because they have since gone out of business, I have ordered replacements, fitted three, and the monitor is now working!

It is sad that a board clearly marked 2007 already has multiple duff components (assuming they are duff). I notice that the bulgy capacitors have cross-scores on the flat end, almost like a hot-cross bun. The scores recall a burst diaphragm, so I wonder if they are a safety feature for components which are considered quite likely to fail explosively! The words written on the items include "VENT", which makes me think that I might be right...

As well as three bulging capacitors there are three flat-ended ones which are also scored, so I hope those are "good".

I do not have an ESR meter but have noticed many discussions of such in this NG over the years...

Thanks to all respondents.

Mike.

Lytics can explode if no such precautions are taken during mfr

NT

Glad you got the monitor going. Seems that many of the simple repairs are just replacing the capacitors around a switching power supply. For some reason the switchers seem very hard on capcitors. They build up heat and will vent the steam. Most electrolytic capacitors are not really dry inside, but slightly moist. When the heat builds up and th epressure is too much, they burst. That could be the reason for the scores on the capacitors, not sure. They will have a way of bursting and venting the steam with a large explosion for the most part.

If possiable you should look at the temperature ratings of the capacitors. Some are around 80 deg C and some are around 100 or more. Always get the highest temperature ratings you can.

Years ago I accidentally put line voltage on a board instead of the +5 it wanted.

They not only explode they stink up the whole room.

ouch

NT

The best stinky component I remember (from decades ago) was the selenium rectifier!

I found that wikipedia has lots about capacitors. But not scratch-and- sniff...

Mike.

If the unit is still open, I would also replace those capacitors. Here in Silicon Valley, they are pretty cheap, probably less than the value of your time even at hobbyist rates.

Agreed, I would replace them. I just got a Samsung 22" monitor (free from CL), the owner said she screen flickered badly until it 'warmed up', taking about 30 min's, replacing these 3 caps fixed it.

Yup. That horrible smell is also horribly toxic.

Cheers

Phil Hobbs

Now I have remembered that in 1961 between school and college I had a holiday job with Radford's in Bristol, UK, who made PA amps for supermarkets. (Quite a new idea, then, perhaps.) Their snooty designer, fully suited, came to review the first of his new design off the production line, and I was one of the erks in attendance. As he bent over it to inspect our workmanship a large electrolytic exploded and decorated him with confetti. There were a lot of badly bitten lips and choked-off splutters...

So I am familiar with the danger, after all!

Mike.

On Sunday, April 22, 2018 at 4:06:05 AM UTC-4, Mike Coon wrote: . (Quite a new idea, then, perhaps.) Their snooty designer,

When I worked in a plant, one of the corporate engineers came to visit. Sh e dressed very stylishly - heels, nylons, jewelry - but incautiously leaned against a rail in the starch room, where we made glue. With lots of caust ic soda. The nylons actually melted off, quite embarrassing. I had to fee l a little sorry for her, but then again somebody would have warned her if she'd been a little easier to work with.