Projection tv picture went out

Unless you have some experience in electronic repair my only suggestion is to have a professional look at it.

One thing I'd like to ask is does the on screen display still work for things like channel indicator or volume?

No. Totally blank just like the set is turned off. I looked at the picture tubes and there is no orange glow. I have done minor electronic repairs. Also, I do HVAC, so I am well experienced in electrical troubleshooting/repairs. If I can positively identify the source of the problem, I can most likely do the repair. I'm willing to give it a shot before I pay someone $75 only to tell me that the repairs will exceed the cost of the tv.

Since you can obviously use a voltmeter you need to start with a print of the power supply and voltage chart at certain test points. You might plug the model number of the set into Google.com and see if there are others who experienced the same/similar failure. Google also might help to secure a schematic. I know by reading some Samsung chassis had common faults for convergence processing components and CRT leaks.

You also might want to pull the chassis out and give it a good visual in plenty of light, maybe something will show up. Visual inspection was always my first step and often can narrow down your trouble shooting steps. Heck it could be something as simple as an onboard fuse or fusable link and those can be checked with minimal effort.

Also certain models had built in error codes that made the power indicator blink in certain patterns depending on thefault. Check into that. Also check that the AC cord is supplying the set. I've seen simple failures like this many times.

Good luck with this. Maybe there is a way to determine what equivalent model Samsung chassis it is? Can you take some pictures of the insides showing the boards?

Just be aware, if you're not already, that CRTs have some particular safety issues. One of which is that they can give you a nasty electric shock long after the set's been turned off.

Sylvia.

Thanks! I AM aware of this. But to clarify things, I have read that such components remain energized long after the set has been turned off. Mine has been unplugged for a week now. How long after being unplugged is a reasonable amount of time to insure all the energy is dissipated? My work schedule has precluded me from doing any further diagnosis since the problem began (last Saturday). However, once I start looking at (energizing) it again, I need to know how long I should wait after I unplug it to start probing around.

To the other posters, I haven't responded since I haven't done anything else yet. But you will be the first to know when I do.

Chris

y

se

has

lem

lse

Hard to believe a charge would still be there after a week but if is was and you managed to discharge it through you, you'd be annoyed and not dead. It's like touching a spark plug. Oh, you haven't done that either? Of course you _could_ use a clip lead and screwdriver to discharge it painlessly. I look at your problem as a fantastic opportunity to get that NEW TV you've been looking at.

G=B2

Some of the material I've read indicates that charge gets embedded (for the want of a better word) into the glass, and leaks out over a period that can extend into months. So you can't assume that leaving it unplugged for a week solves the problem. If you're going near the tube, you need to discharge it, and you need to be aware that if you leave it for a while (a vague expression meaning I don't know how long), then you need to discharge it again.

Descriptions of the extent of the problem range from "not really a problem at all" to "it can kill you". I don't know how to judge between them.

Search Google for discharge +CRT

Sylvia.

While wearing protective eyewear, of course, incase you manage to implode the tube.

Sylvia.

How to discharge your CRT without damaging it or getting shocked:

First, disconnect the TV from AC power!...

Using a long wire clip lead, connect one end of a long lead 10k (2 watts or more) resistor to the CRT ground (usually there is a metal band around the CRT - use that or a connecting metal bracket as a ground - DO NOT use the PCB chassis ground). You will be using the other end of the resistor to discharge the CRT. A safe, easy way to accomplish this is to securely tape the resistor to the long end of a plastic coat hanger with masking or electrical tape, and use the other end of the hanger as a handle.

With one hand, use a 12" plastic ruler to carefully pry up the edge of the high voltage "suction cup" on the CRT. Using your other hand, touch the end of the resistor on the hanger to the anode contacts under the cup. You will see a spark and hear a 'pop' when it discharges (alternately, you could just slide the resistor under the cup until it touches the contacts, but be careful not to scratch the conductive coating on the CRT). Hold the resistor against the contacts for a few seconds. Remove it and move the clip lead up to the other end of the resistor. Now, touch the end of the resistor to the contacts again so that you are directly shorting the CRT to ground.

It's now safe to remove the anode cup from the CRT. While wearing safety glasses, you can use a screwdriver to carefully depress one of the contacts under the cup and then remove it, but be very careful not to scratch the conductive coating or damage the CRT when you do this. After you have removed the cup, short the exposed contact on the CRT to ground again just to be on the safe side. You will probably see a much smaller spark, if any.

When you are ready to reconnect the CRT cable, short the contact on the CRT to ground once more first. The CRT may have recovered enough charge to zap you, so you want to short it out again just before you replace the cup.

h e

It's possible the glass acts like an electret but my suspicion was always that the coatings on the CRT surfaces are distributed resistances and capacitances so when you 'discharge' the tube you really only discharged a 'zone' around the discharge point and the charges will migrate after the short is gone. Or maybe its just magic.

G=B2

e

lf

ic

uch

ine

a u

It's just like a capacitor, hence the conductive outer coating. It can migrate, but not usually to an amount to worry about. Nothing at room temperature has zero resistance, so there is always some charge that will migrate, to eventually even out over the substrate.

u

I'm glad to see someone explaining this in english. I started working on televisions eons ago, before the internet, as a kid, and it took me forever to figure out how to ground out the crt without killing it, me, or other circuitry.

Hard to believe a charge would still be there after a week but if is was and you managed to discharge it through you, you'd be annoyed and not dead.

*************** I found this: "The CRT attached to the flyback has an inherent capacitance which can hold a high voltage charge for up to a week or more after the power is switched off." **************

It's like touching a spark plug. Oh, you haven't done that either? Of course you _could_ use a clip lead and screwdriver to discharge it painlessly. I look at your problem as a fantastic opportunity to get that NEW TV you've been looking at.

G²

************ I have considered a new tv, but since this one is not that old, and considering the cost of new, I prefer to repair it. Anyway, all three (red, blue, green) CRTs went out simultaneously. That tells me that it is probably something other than the CRTs; perhaps the flyback. What do you think?

Well, I finally broke down and sprung the 80 bucks, and had a tech come over this morning. He said the deflection board has to be replaced. He explained how relatively easy it was to do, and that with my experience, it should be no problem. Not to mention, will be significantly cheaper doing it myself. He also turned me on to a couple web sites that their own company uses for parts. I will have to wait until Monday to contact them since I am having limited luck finding the part online. In case anyone has a desire to help me locate it, the model info is at the beginning of this post. I have additional numbers if need be.

Thanks

May not need to take photos, but will if necessary. I know what the problem is as indicated in my other post today. I will try to locate the part Monday. But if I hit dead ends, I can post a photo.

I'm glad to see someone explaining this in english. I started working on televisions eons ago, before the internet, as a kid, and it took me forever to figure out how to ground out the crt without killing it, me, or other circuitry.

**************

I finally located the "no longer available" deflection board for my tv. Ordered it today. Will post the results when I get it replaced.