Zenith Projector 1985 - Page 8 - Videokarma.org TV - Video

JesusJones · #**106** 11-06-2008, 10:50 PM

He he I have the tube on the way already.
And thank you very much. I am Proud of myself.

I just really wanted to make sure it wasn't an internal problem. And now that all is well I can start to try and figure out why the red is way off too the left..hehe more fun for me.

Thanks a bunch folks
Rudy

Keefla · #**107** 11-07-2008, 06:01 AM

now dress her up real nice and lets see some pix of this thing in action

JesusJones · #**108** 11-07-2008, 01:00 PM

I added a picture. But it's pretty poor the camera didn't wanna make it seem as bright as it really is and I couldn't figure it out before the batts died.

P.S. This picture is waaay out of focus(The projector is out of focus). And it's on a green wall.

From this picture you can see that the colours are still rather off. And that there is a dominent red throughout the whole picture. Kinda pinkish.
I've fidled with tone controls and all that but just can't get the right mix.

Probably because all three crt guns vary in intensity. With red being the strongest.

And thats Mario Bros 3 Your looking at. Easily the greatest game ever created.

And if any one here knows. What is the general set up procedure for one of these?

And mbates14 a more specific question.
My projector is set up for front floor projection, roughly how far should it be from the wall???

In the picture the projector was moved pretty far back so I could line up the red with the other colours. The red seems to stay off to the left. If it is too close to the wall. But when it's closer the focus seems better.

Sorry for the jumbled post. I just have alot to ask and say.
Rudy

P.S. These are new pictures off my cellphone.
You can see that red is bright compared to blue and green
Before you would of seen the green just BARELY from the front. ONLY if you squinted really hard (just kidding but you know what I mean)

This image is also nearly 7x7 to 8x8 feet.

JesusJones · #**109** 11-07-2008, 01:25 PM

Also if anyone wanted to know how I "popped" or w/e the green tube back into working then keep reading.

Alright setting this up is harder than doing it.

I used a simple half wave rectifier conected to a 12v transformer to create a steady 7 volts for the heaters. To adjust your voltage you must vary the capacitor you use in your cicruit. Start small and go higher.

Next up obtain a 200-250 volt power supply. I had one I built in school. Put in inside a old computer power supply and gave it some connectors.
Now depending on what tube(big, small) and power supply voltage you have you must pick a suitible resisitor to allow 40 ma to pass throught the cathode. At 250 volts 6.2k ohms does the trick.
E=IR 250/ .04 = 6.2 roughly.

Now the rest is simple. Find your heater pins on the crt. Now take a 12 guage wire and screw in a screw into the wire to make the rubber stretch so you can easily slide it over pins. And use it as a makeshift connector. Connect the heater circuit. Test it out first. If all goes good. (It glows like it should) Move on..

Take the power supply Hook up the positive end to your g2 or 1st grid. (I used first grid) Then hook up your cathode to a wire, put this wire to your resistor NOW I suggest you hook up an ammetere here. So you can make sure your not destroying things or doing nothing.Then hook it up to the negative on the power supply.

So now you have your heaters running on 7 volts.

And your grid has 200-250 volts +
your cathode is connected to Resistor, ammetere then the negative.

Now let the heaters do there thing for about 30 seconds.
And turn on your supply.
When I did this I let the supply run with the negative out of the supply.
And when I finally got the guts to do it. Plug that negative end into the power supply for roughly 2-3 seconds. Do this twice or three times. The less the better.

Now your ammetere should show slightly less that what you expected it to show.

If the ammetere does nothing. Check to see everything is connected properly. try switching G2 and grid 1.

If it still does nothing. Leave the system I just described on untill current begins to flow. As soon as it does, stop! You've probably fixed it.

Now set it up and test it out.
Don't be discouraged if it doesn't work the first time. I had to try about 4-5 times.
And if the first time doesn't do the trick you probably have to lower the resistor you are using. When I fixed my tube I started with 6.2 k and moved all the way down to 2 k before it made a difference.

Start easy and get rougher. Especially if you have nothing to lose!

Hope this helps some one

Oh and if one time when you connect the negative it makes a rather large spark and noise.(Unlike the other times) Stop and see if it's working.
When my tube finally came back this happened wild I was reviving it. Less is better than more.

P.S. Be careful when you do this. I've played with tube amps so I know how not to shock myself.
Slow and careful is better than speeding when it's snowing trust me I live in Winnipeg

andy · #**110** 11-07-2008, 02:51 PM

000

JesusJones · #**111** 11-07-2008, 06:09 PM

hmmmm ever blow out any filaments useing that method Andy?

Sounds like a good way to do it.

andy · #**112** 11-07-2008, 06:44 PM

000

radiotvnut · #**113** 11-07-2008, 07:32 PM

I had an old Philco 19" delta gun tube that was toast. I had that filament so bright that it looked like a light bulb; but, it never blew. I've seen a few open filaments on B&W tubes; but, never on a color tube. Those filaments are generally very strong.

JesusJones · #**114** 11-07-2008, 11:51 PM

hmmmm I might just try to do the green tube again.(using your method though)

I really dont think I was very harsh on it. And it's still not bright enough.
Plus I'm just playing with it.

What was the wattage of the bulb Andy?

But first I'm definatley gonna beat super mario bros on it. Just in case it doesn't work after the second try

mbates14 · #**115** 11-08-2008, 06:41 PM

Quote:

Originally Posted by JesusJones

I added a picture. But it's pretty poor the camera didn't wanna make it seem as bright as it really is and I couldn't figure it out before the batts died.

P.S. This picture is waaay out of focus(The projector is out of focus). And it's on a green wall.

From this picture you can see that the colours are still rather off. And that there is a dominent red throughout the whole picture. Kinda pinkish.
I've fidled with tone controls and all that but just can't get the right mix.

Probably because all three crt guns vary in intensity. With red being the strongest.

And thats Mario Bros 3 Your looking at. Easily the greatest game ever created.

And if any one here knows. What is the general set up procedure for one of these?

And mbates14 a more specific question.
My projector is set up for front floor projection, roughly how far should it be from the wall???

In the picture the projector was moved pretty far back so I could line up the red with the other colours. The red seems to stay off to the left. If it is too close to the wall. But when it's closer the focus seems better.

Sorry for the jumbled post. I just have alot to ask and say.
Rudy

P.S. These are new pictures off my cellphone.
You can see that red is bright compared to blue and green
Before you would of seen the green just BARELY from the front. ONLY if you squinted really hard (just kidding but you know what I mean)

This image is also nearly 7x7 to 8x8 feet.

the green is still very very weak. it needs replaced. or invest into a tube rejuvinator.

JesusJones · #**116** 11-09-2008, 02:23 PM

Alright well to keep people amused. And just to see what rejeuving can do to a projection CRT. I am going to buy a 20watt 240 volt bulb. Witch should come out to 83 ma.
If I can't find one, I might have to buy a 10 watt 120 volt bulb.

I'll do it just like andy said.

Quote:

Originally Posted by andy

My CRT tester applies a voltage between the cathode and G1 with a low wattage 240v light bulb to limit the current. It instructs you to gradually increase the heater voltage to 10v (for a 6.3v tube) and wait until the cathode current reaches about 80mA, and the current limiting lamp lights brightly. Then to interrupt the heater voltage (not the cathode) until the current drops down, and repeat as many as 2-3 times (although I usually only do it once and re-test).

Be back with more results.

Rudy

JesusJones · #**117** 11-11-2008, 11:49 AM

So I go the current to go to 75 ma

The green stayed the same I'd say.

But it doesnt matter I got the new one coming very soon.

As for anyone else with a very weak crt on their hands and nothing to lose, I think this is well worth a shot. And you could easily bring a weak TV or oscillscope back to usable condition.

I don't know how long it will last. For me in the couple hours I used it. It did not get any weaker. So I say go for it.

I'll be back with more pictures and news when the new tube gets here.
Rudy

JesusJones · #**118** 11-13-2008, 12:35 PM

COOOOOL

I got the new green tube! I especially like how it does not look burnt or browned at all

So I think that this tube I got has some sort of gel pack in it or something. Cause looking at the screen of the new CRT I could see bubbles floating around. Either way this made me happy because I thought I would have a great deal of trouble with installing this. Due to a gelpack that would be destroyed as I removed the old one. But that still may be true.

I am puting it in soon and will have pictures to share and stories to tell.

Rudy

JesusJones · #**119** 11-13-2008, 02:41 PM

Super coool

It's been done. It's changed. I managed to reuse the gel pack. I'm sure it must have affected the green slightly but it's hardly noticable if yaknow what I mean.(I don't notice anything)

Other than that IT's working good. (except the convergence but I'll get that sorted out)

Heres some pics
Can you guess witch one is the old one?? Haha

Now I wonder and I'm sure one of you will know.
To make the crts last there longest how should they be running....
Example: Turn G2 up for higher brightness. and leave the actual user adjustable brightness somewhere in the middle.
Or
Turn the brightness way up and leave g2 turned down.???
Any suggestions would be greatley appreciated.

P.S. All pictures are with a sh*^^y cellphone

JesusJones · #**120** 11-15-2008, 08:28 PM

I have managed to improve picture quality a great amount. I used a convergence test screen. It was hard and took me a GOOD WHILE.
In the end it was not perfect but Much Much better. Playing Super Mario Bros it looks almost high def. Hahahaha But it's definatley not. Cartoons look awsome. And movies are definatley watchable.

As soon as I this thing pointed at a white wall I will post many pictures.