TV Repairs

[Rave]

I've just pulled a Sony KV-2900 out of a skip. Apart from a minor crack in the front of the casing which I'm not worried about, it's main fault is that the picture stops about an inch from the bottom of the tube and that everything is (rather oddly) stretched upwards (so people look thin for example). I'm hoping that it's not because it got a battering as I staggered home with it (note to self: you are not Geoff Capes. 29" TVs are too heavy to carry more than 20 yards ). Anyway, does anyone know anything about repairing TVs? Or (on the offchance) does anyone know a repair discussion forum where experts proffer advice for free?

I've found a place that offers a 'no repair no fee' type service, and they reckon to get any TV going for £60, so I'll probably cough up if I need to, but if I can repair it myself by soldering in some new caps or whatever then I'd be inclined to. I already have a Trinitron tubed 29" Sony as my main TV, but this one, although a bit older, is cool because it has switches to manually change between PAL, SECAM and the two flavours of NTSC. For the time being it'll go in the bedroom, in the longer term it'll be ideal for consoles or even for the almighty MAME cabinet I've been planning for ages.

Rich :¬)

[Shogun]

Does the picture stay stretched like that or does it flicker? Could be just the v-hold is out.

[Sk!mD4Rk]

Hmmm, Mame cab. I've done a prototype controller and been meaning to do a cab now for a couple of years but lack of space in my place has put it on a lengthy planning stage.

Try www.avforums.com for TV info. You might be able to correct it by getting into the service mode or engineer mode if it's not too badly out.

[Rave]

Shogun, it stays stretched.

Hmmm, Mame cab. I've done a prototype controller and been meaning to do a cab now for a couple of years but lack of space in my place has put it on a lengthy planning stage.

Well, I'm more at the dreaming stage TBH, and I definately don't have the space in my current place. I haven't even got my Saturn or DC ATM, they're still at my Mum's house.

Try www.avforums.com for TV info. You might be able to correct it by getting into the service mode or engineer mode if it's not too badly out.

I will do. I don't have the remote though so I don't know how I'd get into service mode, and in any case it does look to be a fairly long way out. It is possible to knock the guns out of alignment my rough handling? I had to pretty much wrestle the brute into my flat.

Rich :¬)

[Howard]

If it's fairly old, chances are there'll be some potentiometers inside that adjust various aspects of the picture.

Just be careful when you're poking around... There are some NASTY voltages in there

[Rave]

One hand behind my back, insulated screwdriver, I know the routine. I hadn't thought of fiddling with the pots though, good idea.

Rich :¬)

[Tumble]

I DON'T like big voltages.... 240 volts is bad enough through the end of your thumb

[Rave]

Right, I got it open and there is indeed a big bank of pots in there. The trouble is, I enlisted my wife to help me and she was blimmin hopeless! I really needed someone to go "right, that one's the trapeziod......yeah that one's V-Size" and she didn't have a clue. I think the telly is too far out of alignment to get the picture perfect, but I have managed to get withing 1cm of the bottom of the screen and I can put up with a gap that size, at least until I can afford to pay a proper repairman.

What I really need, now that I've properly screwed up the tilt and pincushion, is a BBC test card to get it all pukka again. I taped one ages ago but god knows where the tape is. Is it possible to download one and then set it up as the second display out from the TV-out on my video card? That would sort me right out.

Rich :¬)

[SilentDeath]

"it's main fault is that the picture stops about an inch from the bottom of the tube"

Is there any smudging of colours? or is it a cleanish sort of line where it stops?
If the colors are smudged around where it stops it mean the phosphors have moved and the tube is then fked... usually happens when they get dropped... or hit something. I have the moved-phophors in the top corner of my 21" montior where it hit the side of the stairs when I was bringing it in.

[Rave]

Is there any smudging of colours? or is it a cleanish sort of line where it stops?
If the colors are smudged around where it stops it mean the phosphors have moved and the tube is then fked... usually happens when they get dropped... or hit something. I have the moved-phophors in the top corner of my 21" montior where it hit the side of the stairs when I was bringing it in.

No, it's a clean line. I've managed to moved the picture down by twiddling one of the pots, it now stops about 1cm from the bottom of the screen which I can live with. I guess some components are too far out of spec to get it perfect with the adjusters, probably capacitors that have dried out a bit.

I don't think you've moved any phosphors, it'll be the shadow mask that's moved. Whatever they are.

I've posted a thread in graphics asking how to output a test card from the TV output of my graphics card, check it out please graphics bods.

Rich :¬)

[Rave]

Right, well I've got it quite good. The big problem now is that the picture is stretched out in the middle and compressed at the edges, so everyone in the middle of the picture looks too tall, and titles and stuff at the bottom of the screen look all squashed. There were two pots that I was too scared to tweak because their position left me open to electrocution if I slipped- one called itself h-phase and the other was a large pot on the circuit board that was attached to the back of the tube itself. Anyone know what these do, and if they'll solve my problem?

Rich :¬)

[Jonny M]

H-Phase is probably horizontal phase, and will fix the "people in the middle looking thin" problem.

No guarantees though

[SilentDeath]

I suggest you post this on bit-tech electronics forum, lots of people there have fiddled with tvs before

[Rave]

repairfaq.org reckon I need to adjust the 'vertical linearity'? I could try the H-Phase I suppose, although I shall have to do it with the telly switched off, don't want to kill myself.

I'll try the bit-tech forums if that doesn't work, I haven't had any replies on avforums.

Cheers,

Rich :¬)

[Rave]

Hmmm....according to a page I googled, apparently horizontal phase adjusts the horizontal positioning of the picture, which I need to do. Won't solve the main problem though .

Rich :¬)