SnM

i have a bad computer monitor. it sometimes is fine, but the it will start to freak out, start frizzing out. at this time, it also makes a static noise. sometime is just does it for a bit, and then returns to normal, but then sometimes it gets worse, and the monitor tries to reset it self, and when it gets real bad, the monitor gives up and shuts off. i then need to unplug it and plug it back it so i can turn it on, and then it usually continues to freak out.

now, i can cause the monitor to start frizzing out a bit by hitting/bumping into it. this is leading me to believe it is a loose connection of some sort in the monitor. this problem is getting worse and worse as time goes on.

i know there are high voltages inside, but i have never opened one up, nor have i opened up anything similar. is there anything i should look out for? i want to see if something is loose. i do have a replacement one now, so it is no rush to get this thing working. any ideas or help would be great!

btw, this is a KDS 21" visual sensations monitor. my thrid one too. first two had pixels out. just missed the warranty date too! :x

Thanks,

steve

Optikon

Third one...? Take the hint! This company does not produce quality products! :-)

zachtheterrible

sorry, i accidently posted this twice, and can't delete it.

zachtheterrible

WATCH OUT FOR CAPACITORS!! They are cylinder shaped usually, and the big ones are the ones you want to watch out for. They might be shaped in other ways (i'm not sure), but if it says uf on it, it's a capacitor. Don't worry about the little ones. Anyway, a capacitor stores electrical charge, and will nail u if you touch the two leads at once :shock:.

TillEulenspiegel

If you are unfamiliar with monitors or basic electronics concepts, I do not recommend that you mess with the thing.
The monitor even when unplugged case store lethal voltages. If you choose to fool with thing your responsible for what happens.
That being said clearly.........

I would proceed as follows.
Rest the monitor on its screen on a soft serface..towel or what ever.
Remove the case , the back of the case has a "safety interlock, which means that you can't power the monitor with out the case being on. I remove the plug from the case , it's usually held by either a metal clip or a shaped plug, prise it from the case.

Take a jumper cable with alligator clips on both ends ( or fashion one from a wire. Ground one end to the chassis metal ground, attach the opposite end to a plastic handled screwdriver ( flat) . On the side of the monitor you will see a rubber wire with a "suction cup" looking thing CAREFULLY place the grounded screwdriver to the underside of the suction cup ( picture tube side). This will discharge the most dangerous voltage..you should hear a "snap" from the discharge.

Now, look at the bottom of the circuit board, start at where the power plug joins. Look for any evidence of arcing or loose joints , blackening, dis-coloration.. There are several components that generate heat that look like the photo ( in the middle the aluminum heatsink just above the word "Caution" hehe ) jiggle the heatsink and see if the pins or the traces of the pc board move if so solder them and apply a heat resistant adhesive ( hot glue sticks are great) to the heat sink where it contacts the board.

The next step to follow if you can't discern by eye what the problem is........
Plug in the monitor ( without the back on ) power up your 'puter. Prop it up a bit if you need to see the picture. Take the screwdriver ( disconnected from ground) and tap gently , with the plastic handle on the circuit board and you will find ( if it exists ) the faulty connection. %90 of all monitor problems stem from two causes, a blown horizontal output or ( more common ) a melted connection from heat generated from regulators.

Attached Images

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Exo

Check for dry solders, the fact that it makes noises would suggest you need to focus on the power supply/high tension circuit.

Also try to clean the backside of the picture tube, around the rubber thing (don't know the english word for it ops connected to the high tension transfo. Dirt may cause the high voltage to 'spark' to the grouned part of the tube...

and, indeed, watch out for capacitors, especially the big one in the power supply. On a working monitor there shoudn't be much charge left on it, but depending on the defect, there might be charge left in it...

SnM

okay, thanks. i'll be carefull. probably open it up next week or the following week. I figured the caps would be dangerous, so i'll take your advice on how to discharge them. i'll let you know what i find!

thanks again!!

steve