Sony Black Trinitron 24" with weird colour (pink)

Does sound like the CRT to me.

Mark Z.

Ok, and assuming it's a CRT problem, is there any way to adjust to make it last for, let's say, some months? Increasing screen grid should improve something in this? I know it is a bit dangerous because it might fasten the CRT distruction..., right?

Thanks! Edu

Mark D. Zacharias ha escrito:

Me too. Do they still sell those CRT boosters? They increase the filament voltage a little, thus the cathode burns extra hot which is supposed to burn off some of the crud that builds up on them.

The retrace lines are possibly another problem.

I am a person who tries to fix everything, but maybe it's just time for a new TV. They are so cheap these days that when the CRT is dying, why even bother fixing it. You can probably get a new TV cheaper than a CRT.

Mark (who used to putter with electronics when I was much younger).

First let's get the color straight. The opposite of green is magenta, not pink. You said changing channel caused the screen to turn green. Is that real or an optical illusion?

A knowledgeable person could try adjusting thing like the crt drive and cutoff adjustments. Might help a bit. In my experience Sony tubes don't fare well in rejuvenation attempts - they often seem to die altogether.

Mark Z.

I'm not a knowledgeable person, but I can try...:-) The CRT drive is the adjustable "screen" HV which comes from the FBT and goes to the CRT board? What is the cutoff adjustment? Is it something which cancels the ray during retrace? Where can I find some adjustment for this?

The green colour instead of black is not an illusion. It is quite strange. Where it should show green it shows grey, and where it should show black it shows green... 8-|

Thanks for all the replies!

Eduardo

Hello again1

I have found that there is a way to configure some parameters in this tv set from the remote control. I need to enter service mode, but..

1) My remote is old and the ink cleared, so I cannot find the "disp" button 2) What is "PWR-ON" ??? My remote has a green "power off" button but it doesn't turn it on again? Is it talking about turning on the tv set amnually from the switch in the set? 3)Where can I find a photo of my remote control so I can check what the rest of the buttons do? My remote has buttons in both sides, one side has a reduced set and the batteris, and the other has the complete set. There is a slide cover which can be turned so it covers the other side...

Thanks! Eduardo.

'Ya gotta bad yellow gun.....Buy a new set.

sky ha escrito:

"bad yellow gun"... yeah, right

I think you got a lot of bad brain cells. Buy a new brain.

Hi, CRT is last thing in the list. Check the green drive. This drive circuit goes most often. If CRT is really shot, Nothing much can be done.

Why buy a whole new set when he could just buy a new yellow gun?

Or perhaps have this one re-filled.

(for the op, this is foolishness, pay no attention)

Ken

Hmmm, Really? Poor joke!

Seriously (please...) anyone can tell me how to enter service mode? There is no service mode button in the back. I have to use the sequence: Pwr-OFF -> DISP -> 5 -> VOL + -> PWR ON

What is Power-on? Pushing the main switch? And PWR-OFF does mean the button in the remote, or from the mail switch?

Thanks! Eduardo.

Tony Hwang ha escrito:

yes, but the OP does have some green output, hence its pink.

Without testing it I'd say its more likely a video drive problem, but it might well be a crt fault. Its not falling crt emission, if it were just that you wouldnt be getting green retrace lines. I'd measure the voltages on all the non-EHT tube electrodes to see how the green voltages compare to the other 2 colours. Also I'd measure the amount of green drive vs red and blue. Tjis should tell you whether the prolem is crt or video drive or other electrode voltages.

If the fault is the crt, you might be able to burn off an internal short, if not its well & truly had it.

If the fault is video drive, thats usualy fixable but not in every case.

If its other tube electrode voltages, thats the easiest to sort out.

There is also the final possibility of very low green emission plus someone has unably tried to tweak the drive/background to comppensate and has screwed those settings up. In this case the set would have very slowly got pinker and pinker over time, so you should usually know if is this or not. Low emission is easy to fix on most sets if you know a bit about electronics.

If youre not familiar with the dangers inside tv sets, learn first or leave them alone. TVs and microwaves are the 2 household appliances you really should not mess with unless youre upto speed.

NT

Hello Peter, thanks a lot for your useful reply!

I have an oscilloscope. I will ASAP check differences in voltage for all 3 colors in the CRT neck, right?

How can I burn an internal short?

I will try to check if variations in screen voltage improves something.

I'm not sure of what you are saying... "Over time" do you mean along days/months or along first minutes since turning on? What I have checked is that the effect (green fault except when pure black) diminishes along some minutes since power on. The effect is at its top when powered on.

All I know is I have to unplug mains, discharge capacitors, discharge all HV from FBT to tube grid, and after some seconds try to discharge again.

Is it reasonable to try to enter service mode in the OSD to tune some parameters???

Thanks!

if its a battery scope, maybe, if its mains, uhoh. A multimeter is more pratical and less likely to make anything go bang.

pass a wallop of current thru it.

no, that wont do anything. Just measure the electrode voltages and compare the 3 channels. And of course dont touch THAT electrode.

months

then you need to read understand and follow what I said, or we may not hear from you again.

doubt it. Not whats needed anyway.

NT

It is mains.. So I will use a multieter, ok.

Could you give more details? I have read about placing a 15K 2W resistor between each color cathode and GND to test if the screen turns to each color on its maximum intensity. Is this a right test?

I hope you can hear from me again...:-)

Ok, so, thanks again! Eduardo

eek. You need to familiarise yourself with the safety issues before getting in there.

pass high i thru thru the short for a couple of seconds. Vapourises it. Shorts occur between 2 tube electrodes. But ATM you havent found a short.

no, the needed tests have been explained already.

indeed, this is why you shouldnt do anything but read yet.

NT