Sony Trinitron KV-21XMTU

[andyw25]

Hi all, another item iI need some advice with, my Trinitron that iI use for all my Vintage gaming equipment has a slight issue, it works well but the picture has a slight tilt and appears to be off centre. iI don't think it has a service menu as it's an older set, does anyone know how iI would go about adjusting the tilt and position of the picture?

Pictures to Follow

Many Thanks, Andy

[MALC SCOTT]

There will be horizontal/vertical shift pots you can adjust to centre the picture. The scan coils need to be adjusted to level it up.

[andrewn]

I've got the same set, in fact I got it out of storage a few days ago to see if it was still working and I was impressed with the picture quality. Looking at the service manual all the adjustments are on board J1 which is where the SCART socket is located. The adjustments are:
RV1508 Horizontal centre
RV1504 Horizontal size
RV1506 Vertical centre
RV1507 Vertical size
RV1509 Vertical angle
RV1503 Pincushion amp
RV1502 Pincushion phase
RV1501 Pincushion correct
RV1505 Corner correct

Hope this helps. This TV uses the AE1 chassis so these adjustments are likely to be the same for other sets that have the same chassis.

[Maarten]

There could be some external magnetic field or the deflection yoke could be sagging. Sets don't go out of adjustment all by themselves, and there is no other adjustment for rotation than the yoke itself.

[MALC SCOTT]

Check that the black rubber wedges have not fallen off the crt. They fit between the scan coils and the crt.

[andyw25]

Thanks for the info so far guys, ive (I've) repaired many things in the past but never done any work on a tv before, ive (I've) always left alone due to the high voltages, should Ii just leave it unplugged for afew days to discharge before removing the back cover?

It has sat in the spare room at my Grandmothers for several years and worked perfectly before that, but it has been moved and transported back home and set-up which is when Ii noticed the wonky picture.

The picture does seem too big as well, Ii currently have the PS1 set up playing Tomb Raider and even using the in game screen adjust there is still picture information lost as it's too big for the screen, also when using other Consoles the picture is not centred, it's off to the left so im (I'm) thinking the horizontal size and position needs adjusted at the very least.

Thanks again for the info so far, Andy

[Studio263]

We used to see this fault a lot with this model, what seems to happen is that the sticky tape that they use between the scan coil clamp and the tube neck goes "gooey" and lets the whole lot slide down the neck a little, often adding a twist as it goes. If you carefully undo the clamp and relieve the plastic fingers underneath away from the tape you will be able to push the coils back into the right position, which is as far forward as they will go and twisted round so that the picture is straight.

These sets have a 3 core mains lead and an isolated chassis (for the SCART conections etc) so there isn't a great deal in there to worry about. One thing to watch out for is the scan coil connections as you are squaring the picture up, the one with the thicker red lead going to it will give you a nasty shock if you catch hold of it (from frequent experience with many types of set!).

There's plenty of re-soldering to do while the set is apart, IF module, voltage regulators down the middle, the edge connectors for the stand-up panel at the back, anything else that takes your fancy... Good set though, makes the moderns look a bit sick.

[andyw25]

I've had a little adjustment with the pots on the board inside the tv and there is still a very slight tilt at the bottom of the screen but im (I'm)happy enough with it now to live with it, although on closer inspection the whole screen wasn't tilted, with the test card generator on the top of the screen was perfect, it was just the bottom left side that tilted slightly.

Does anyone know a good way of getting rid of dust from the inside of a crt tv, Ii was shocked when Ii removed the back cover, it's about a cm thick with dust in places, Ii didn't want to stick the Hhoover in in case Ii damaged something or caused current to come up the Hhoover pipe?

Many Thanks, Andy

[gec2110]

A dry paint brush and a light suction Hoover, always best to remove CRT base first.

[andyw25]

Hi all, Just wanted some advice with this Television.

Still being used for watching old Tele or playing Vintage Consoles on. It does produce a good picture, however it does have a couple of small niggles i would like to address.

When the set has only been on for a short amount of time, the green display for channel number and volume etc flickers in brightness from normal bright green to a very dark green, but once the set is warmed up after an hour or so it's perfect.

Also i seem to be loosing some Horizontal picture information, the vertical is perfect and when the back is off the set is off I can adjust the vertical so much that i have huge black bars top and bottom so nothing is wrong there.

However the Horizontal is adjusted as far as it will possibly go and yet the horizontal is still too big as there is picture information lost either side, it needs to be adjusted further but the adjustment is at the maximum, what could be the cause of this? Dried up Capacitors somewhere perhaps? Could a Capacitor problem also be the cause of the green volume/channel indicator flicker?

Many Thanks, Andy

[samjmann]

Hi Andy,

I remember my I had a Sony set of my own that I'd bought as scrap that did something similar. The green OSD flickering turned out to be nothing more than careful re-adjust of the CRT G2 or A1 control depending on your terminology. The excess correction of pincushion distortion was normally caused by a electrolytic going low value in E-W modulator control. This was a fairly common fault at the time.

Sorry I can't be more specific with component references, a hairdryer and a tin of freezer should soon show it up.


P.S. Like the Avatar of the Grundig 2X4 Super. They were the dog's b******s in their day

[Studio263]

Regarding the width problem, a lot of Sony sets are like this and give just a bit too much width even with the control on minimum. The only practical way to reduce it further is to change the value of the tuning capacitor in the collector circuit of the lie output transistor but be careful if you decide to experiment with this. Ensure that the HT rail is correct before you start and only make changes in small increments, keeping an eye on the EHT the whole time as it will be affected.

[andyw25]

I do think there is something at fault within the TV, be it a capacitor issue or something else. As it isn't just a little bit of Horizontal information lost, it's quite a lot, so much so that even just playing a DVD for example, say for example a BBC DVD that has the copyright warning at the beginning, the text on the right side is very close to the edge of the screen but the left side, parts of or whole words disappear off the edge of the screen, it never used to be like that and i just can't imagine Sony selling TV's that cut off so much picture information. It's really puzzled me to say the least as it appeared out of nowhere, would love to get it ironed out and back to normal if I can as it's a very good set with this fault aside.

But I'm a bit out of my depth when it comes to televisions sadly, I can do all manner of capacitor and parts replacements but with the high voltage involved its more a case of what I can do that can be easily achieved avoiding high voltage areas. If it's something in a high voltage area that needs work I wouldn't be afraid to do it but I would prefer to discharge high voltage first and that is something I would need advice on doing if possible.

I'm hoping it's just something simple like a bad Capacitor or a Transistor but as I say when it comes to televisions im far from an expert so any advice at all in trying to locate the fault would be greatly appreciated

Many Thanks, Andy