television goes again by hitting the top of it?

The picture tube is likely fine, this is a problem far removed from it.

Something is making bad contact, either a connector that is no longer making contact all times, or a bad solder joint.

Michael

It has a Whack detector security option you turned on?

If it does, you better stay away from it.

-- Service to my country? Been there, Done that, and I've got my DD214 to prove it. Member of DAV #85.

Michael A. Terrell Central Florida

Bad solder joints. Take it to a tech.

Probably a bad solder connection on the circuit board, or a component that is going mechanically intermittent. Take the set to a service centre, and get it properly fixed.

--

JANA _____

Thanks but I want to give it a go myself, for 2 reasons, the cost of servicing compared to buying a new similar tv and I am reasonably handy myself with although limited electronic knowledge. I know there can be dangerous voltages left in the capacitors after turn off so I presume if I short the power plug phase and neutral pins to the earth pin I will discharge any voltage in the caps. The fact that it responds to a tap on the top of the tv makes me think it is probably not in the circuit board, it has settled down at the moment but the next time it goes haywire I will trying tapping different parts of the tv and see if i can narrow things down a little there before opening it up. Is it possible for dust to cause this sort of problem or are there no conductive parts exposed to the dust?

It's cracked solder joints on one of the boards, take it somewhere to have the problem fixed. Stop using it *now* and certainly stop whacking it, quite a few TV failures start out as solder joints then much more severe damage occurs because people continue to use the things.

Thanks, leaving solder joints out for the moment where am I best to look for this, I will trying tapping different parts of the tv and see if i can narrow things down a little there before opening it up so you may want to wait till i have done this before you answer my question, thanks.

I will look into safety measures before working on the inside of the tv and i certainly will not try working on it with the power turned on.

It's on one of the boards, guarranteed. When you tap on the top, the vibration passes through the entire chassis. Pull the back cover off and poke around with an insulated stick, a wood dowel works pretty well for this. It shouldn't take long to find the ticklish spot, at which point you can figure out a way to access the solder side of the board and touch up any suspect joints. It may take a couple passes but if you can solder and have some common sense this should be within your ability to repair.

You pretty much have to work on it with the power turned on, just shut it off and unplug it before you try to solder anything. Usually there's enough slack that you can leave the HV anode lead connected to the CRT and not have to discharge anything. Just give it a few minutes for capacitors in the power supply to discharge and treat them as charged.

Thanks for the great advice, as you say with this advice and a bit of common sense I should stand a good chance of fixing it. When it first happened I just assumed it was a capacitor problem considering it's age and so was just going to abandon it but when it responded to a tap I thought it might be too soon to give up on it. The only difficulty at the moment is that the problem has settled down a lot, so I will have to wait till it gets more flakey as the act of taking the cover off will probably be enough to get it going again and at this stage it can keep going for quite sometime before it flakes out again which makes faultfinding difficult.

Just go for it, when you start poking around, it's very likely the problem will occur once you start flexing and tapping things.

Not sure why you think i am a troll, I guess what I said is not totally correct and maybe even dangerous, but I always intended to check with a web search exactly what to do, all I really know is that the caps will hold a dangerous charge which i need to discharge somehow.

You thought it was the "cathode ray tube." Have it fixed by a tech, you don't know enough. Also there are some capacitors in that set that should be replaced.

The problem is a little knowledge is likely worse than none, because a bit makes you think you know how to fix the problem.

People have stated what they think the problem is, and you think you can define what's wrong by how much of a tap you need to give the set?

And I don't really know what that nonsense is about shorting things, but until you can make sense in that area you shouldn't be going near the insides of the set.

Michael

Very wrong, and a good way to die. see:

No, it isn't. There is a 99.5% probability of a cracked solder joint. The other .5% is a damaged connector. If you look closely at the solder work on the PC boards you will see more than one cracked joint. the more you beat on the TV, the more damage will occur from the vibration.

Wow, it's become clear real quick who to add to the killfile, sorry to those who will now see this post because of my reply, rest assured I will add all further trolls straight to my killfile

Thanks, I should not really have said that as I knew it was not quite right, all I really knew was that the caps would retain a dangerous voltage after turn-off and would require discharging, I was laways going to research this bit before going ahead.

Thanks for clearing that up, the advice here has given me a chance of getting the tv going again, if the problem lies outside the scope of what has been suggested here I will obviously give it up as I do not have the technical knowledge of the workings of television.