CurtPalme.com Home Theater Forum

[Curt Palme]

The brightness shift is due to the ABG, that's normal in the first few minutes. I thnk you have a short in the green tube. To test, transfer the green tube to the blue tube position. YOu need to put the blue tube into the green tube position and connect all wires, but the HV lead will not be long enough to get to the HV splitter. Connect all yoke wires, and you can see if the green tube works in the blue position, as it will use all the blue circuits instead of the green.

[Curt Palme]

The brightness shift is due to the ABG, that's normal in the first few minutes. I thnk you have a short in the green tube. To test, transfer the green tube to the blue tube position. YOu need to put the blue tube into the green tube position and connect all wires, but the HV lead will not be long enough to get to the HV splitter. Connect all yoke wires, and you can see if the green tube works in the blue position, as it will use all the blue circuits instead of the green.

[skyraker]

Hi Curt,

the tubes are nearly new (350 hours). The Preowner let built them into the CRT by "spatz-tech" inkluding a colour-calibration. He never changed the Gain, Bias etc. after build in. He just screwed at the convergence.
Is it really possible that a tube has a short after this time?

[skyraker]

Hi Curt,

here are some news. I hope it will help you a bit.

- I set "ABG Mode" to "off"
- I set "All white mode during warm up" to 0 Minutes
- Contrast is set to 20
- Bright is set to 45
- I reseat the CRT socket of the green tube

Now i switch on the crt.
No warm up "all white". Red and blue are logically dark, but green lights up with five stripes trough the picture.
Pressing the menue button shows the menue normally and sharp. Just the green tube is much too bright. It looks like the power of all white is set to the green tube at all the time.

Here are two pics of it. I hope it helps.






In this setup it runs some minutes. Then i turned off the crt cause i don´t want to destroy something else
There was no error code during this time.

[skyraker]

Mhh, i wanted to check the bias and gain settings. They are at standart settings.
Looking at the bias menue was no problem. Then i switched to the gain settings where the "Pattern with the gray stairs" was automatically shown. That was too bright. The CRT shuts down again with the error code 39.
Starting is not possible. 2 seconds -> off

[skyraker]

Interessting:

The green tube is "cut off" and still on.

[macgyver655]

It would be easiest to swap the tubes like Curt said. That Green tube is either bad or the G2 is set to high. This could be either an adjustment or a bad component. Swapping tubes would verify the green circuit as the problem or not. It would also verify the tube.

You can play all you want but this is probably the only way you can verify.

If the harnesses to the neckboards are long enough you could swap that way but I dont know if they are. You dont need to swap HV wires or deflection,convergence, focus or astig if it has it to verify.

[skyraker]

Hi macgyver,

i don´t want to play. I just wrote down the things i noticed.
I thought they could be helpfull for a diagnostic.

[macgyver655]

No offense was intended. I'm just being specific as to what needs to be done.....

Anything else you do is just time consuming and has no pertinent information in the diagnosis.

[skyraker]

Mhhh, it´s not my day.

I put the green tube to the blue position. Then i have connected all wires of the green tube inkluding the HV cable on the blue position.

Effect -> The same as before. The tube lights up too bright with the five stripes through the picture. Then the CRT shuts down with error 39.

So the tube is damaged? If it´s right: How long is the warranty of a tube. It runs only 350 hours. Its a tube from VDC installed by spatz-tech in germany (a "big" crt dealer).

Greets
Thomas

[Curt Palme]

a 1 year warranty for the tubes, 15 months from the VDC sell date I think.

Yes, the tube is bad, the cutoff level has changed. Talk to Spatz..

[Curt Palme]

a 1 year warranty for the tubes, 15 months from the VDC sell date I think.

Yes, the tube is bad, the cutoff level has changed. Talk to Spatz..

[skyraker]

Yes, i think i´ll talk to them tomorrow.
Three tubes inklunding the mounting for over 2,5k € is not really cheap. I hope they will be cooperative.

Is it possible that i have killed the tube with "resetting the convergence" or "setting the Bias and Gain"? That´s all what i´ve done.

You said the tube is bad. It couldn´t be any parts mounted on the tube? I just ask because i don´t want to tell something wrong, so that they laugh about me.

Thanks
Thomas

[skyraker]

There ist one more question please.

"the cutoff level changed"
What does it means? What changed in the tube?
And, what could be the reason of this changing?


Thanks
Thomas

[CIR Engineering]

There may just be a piece of dirt inside the tube neck and the tube may be repairable.

The first thing to try is running the projector, and tapping the tube neck with a non-conductive rod. Use a wooden rod and just tap the magnetics along the neck of the tube. If you can shift the dirt it will burn off and the tube will go back to normal.

If that doesn't work, you can pull the green tube out. Stand it upright with the face of the tube pointing down onto the floor. Tap all around the magnetics harder this time (but not hard enough to hurt break the glass). You may also want to lightly bang (drop) the front of the tube onto a hard wood floor or something like that. Again, the idea is to dislodge the dirt.

Another alternative is to just run the projector. This might burn off the dirt over some hours.

And lastly, a Sencore tube restorer might be an option for burning off the dirt.

Then again, it could be a bad connection inside the neck in which case the tube is dead. But often these can be fixed.

craigr

[skyraker]

Hi craigr

I did what you said ->tapping with a pice of wood around the neck.

The tube didn´t light up so bright now and the stripes are gone away. The tube looks nearly ok. I can play every pattern where the crt shuts down before. Now the tube just lights up a little too bright. This should be the G2 which regulates himself with ABG on after 20 minutes? Or is there another "mistake / defect"?

Picture before:



And after:






Many thanks
Thomas

[CIR Engineering]

Excellent

Now just run the ABG for twenty-five minutes to establish a G2.

The G70 ships with the GAIN set to MAX. Check this, and if it's at MAX reduce it to something below 225 (I suggest around 200). Then set your grayscale after that. Keep the green GAIN at your established setting and work around that.

If after running the ABG you don't like the solution that the G70 comes up with, just do it again. The G70 ABG seems to come up with a very different solution every time it is run. With ABG turned on, power cycle the projector off/on. Wait 25 minutes, and see if you like what the G70 comes up with this time.

The ABG on the G70 is quirky. Some G70's seem to need to have it enabled and others don't for correct black level. I always leave ABG turned off whenever I can after the initial 25 minute run.

craigr

[skyraker]

The green tube is in the blue and the blue in the green position at the moment.
I´ll put them back tomorrow and hope that everything is ok after running the "ABG Mode on" for 20 minutes.

ABG turned off?
I read that the ABG has set to "on" if the tube are in good condition and "off" at older tubes.
I´ll check it out whether it´s better to leave it off.

But first the tube has to run fine on its place. But it looks good (i hope)

Thanks
Thomas

[skyraker]

It´s me again

The tubes are back in their positions. AND, they are working fine.
No error, no stripes etc.

I talked to Spatz and Mr. Sperrling said the same. There must have been phosphor particles in the tube.


I don´t know what to say. Many thanks
Thomas