Zenith Projector 1985
 

Found this CRT projector at a garage sale. It was only 10$ and I hoped it would be something simple that was wrong with it.

After cleaning the entire thing and powering it on. You can hear a loud crinkly/static noise coming from the HV area right after powering up. Like most Tv's do (I think this is normal, and mention it for elimination from troubleshooting)

The other thing I hear is a buzzing/ticking from near the power supply's transformer. This starts a couple seconds after powering on. Either the power supply is screwy. Or something else is making the power supply trip out. One thought was the large 680uf 200 volt capacitor. It's large and looks just slightly bulgy. Anyone think a 28 year old cap would dry up?

I have also seen the crt's flash when you flick the power off. (mainly the red one)

I post this here because the projector is basically a color TV but it has a CRT for each color. And should be similar in trouble shooting.

Here's a picture of a working one. Anyone remember ever watching one of these?
http://farm4.static.flickr.com/3248/...0c5e4c.jpg?v=0

Thanks for reading
Rudy

Alright Regardless of what I have said I now think it is an HV problem.

Using a fluorescent bulb in the dark I put it near the heavily insulated Hv lines. That go to the suction looking cups on the CRTs. When you flick power on the bulb glows momentarily. I could also see some HV leakage arcing.(Should this happen at all) Then it stops glowing. Once again when you power it off, the bulb glows momentarily.

Also when you power off the projector the CRT's often give there only sign of life at that point with a quick flash. Much like the bulb did when turning it off. This leads me to believe HV failure.

I have a few questions about the HV wires. Do these wires slowly loose there ability to insulate?

Do these wires change resistance like spark plug wires?

Or should I be more focused on the HV transformer area and horizontal deflection sections of this projector?
Any one had a similar problem with solid state?

Thanks for your time
Rudy

Okie doke

I got this bad boy singing! But it's not total victory yet. The green tube is not lighting up at all. But both blue and red are working strong.

I'm guessing i'll need a replacement crt or rebuild. Does any one know of a place I could get this done Or find the new one?

Thanks Rudy

I'll post pics once my computer will let me

I remember these Zenith projectors back in the 80's.Not equal to most of the data grade projectors of the same period, but good enough to give you a large picture (if you didn't mind the scan lines). I think most of these were basically video grade only, but I could be wrong.

As far as hunting down the problem with the green gun, you could start here and ask Curt
http://www.curtpalme.com/
If it's a crt rebuild,Curt could direct you to a company that still does this.

or you could take your chance with the AVS forum (CRT projectors).

swap the crt boards from the red to green or blue to green i mean unplug the green board an move either the red or blue over to the green tube. dont disconnect the connectors on any board just move the red or blue to the green crt and see if you have video. you might have bad green drive from the chassis or a bad green crt board. steve

beleive it or not I've already sent curtpalme an email, he hasn't replied yet though.

Swapping the crt boards is an excelent idea. I planned on checking all the voltages on all three boards but swapping them for more instant and rock hard results sounds even better.

I'm hoping the tube is OK. I don't think finding it would be very easy. And rebuilding from what I've heard is rare and expensive.
Thanks
Rudy

I know that you already know this, but i will say it in case you don't. Crt projectors usually have switches to turn off individual crt's during the set up and alignment process. sometimes a previous person might have flipped switches just because they can. Also Does the green crt filament light up? swapping out the crt boards is also a great idea as mentioned before.

OOOOOO switches eh? I did not know this, but it makes sense that it would.

I will take a good look over for some switches.

And yes all three filaments are glowing red as they should be.

And don't asume I know anything! I am only 17 and very clever and know alot about electronics. And have fixed and worked with tubed devices mostly.(amps, tvs)
This is my first solid state challenge. But it's the same principals.
And I am more than eager to learn.

So everything you guys tell me helps.
Thanks again
Rudy

Getting a tube for that might not be too bad-I think there are a few places that do rebuilding on them. Since they are monochrome and rather small they wouldn't be so hard to do. I have seen projector crts on ebay on a regular basis.

I know where I can get a Panasonic similiar to this-the guy said I could have it, but I really don't have the room.

OK so the green is working. But it is not very bright.

Dead tube or other....???

It was probably working the whole time. I just never starred directly into it.

I tried switching the baords around but it proved to be difficult with tied in wires that didnt wanna move that freely.

But I hope the fact that it is actually working just not bright enough will bring some more conclusions...like weak crts....??(Also I noticed that the green focus or something was set to "high" unlike the red and blue that were set to medium)
Also the picture is upside down. Maybe this has to do with distance or something.....I donno

Rudy

Have you tried injecting a video signal into this and projecting it onto a wall or something to see how it looks? You might be able to turn up the screen control on the green gun if that is even needed and get a decent picture out of this thing. Never know, you just might end up with a great ten dollar find.

Yes I tried playing some Friends.

The red plays strongly. And blue is there.
But the green plays much to weakly to get any effect from it.
And I cannot find any brightness control on this unit.

And still the picture is upside down. Was this thing ever mounted upside down?

Rudy

Yes, It probably was a ceiling mount, but most projectors i've seen have a way to reverse the picture, some had a menu option you could select, some like my antique Barco V-star you had to individually reverse connectors on the yokes.

I have a Provision 750 which is a Zenith comercial projector. To change the settings for floor/ceiling, and front/rear projection there is a board with jumpers (I think) that are changed. All you are doing is changing the yoke connections though. You really need a service manual to help with setup. There may be a service menu that will allow you to turn down the red and blue to match green. This will reduce brightness, but may make a useable picture in a dark room. These weren't very bright to start with. You may be able to find a complete set of projection tubes on ebay which would be a good idea. If you replace only green you will likely not be able to get good gray scale. And by the way do not look directly into the front of the projection tubes, it could harm your eyes.

Bill R

Since this is your first experience with a front projector, you really should try to find a user/install manual or seek advice from someone that knows this particular projector. If your intention is to learn how to fix them,seek some help from those who have the experience. This is not to say that there isn't anyone here that can help you, but since you are a novice, you can really cause some further damage or hurt yourself if you go at it willy nilly.I speak from experience..

The green gun gets most of the work in a 3 crt configuration.Maybe this is why it's weak. There are some G2 controls on projectors, but I'm not certain about the Zenith you have. Also, there usually is a switch that turns off each gun for sizing,geometry alignment,purity,etc. If not, then you would cap off each gun on the front and only allow the channel you want.
Some projectors have a switch that changes the image from a floor mounted position to a ceiling mount.Others have option pins that you change with jumpers.

Again I would suggest that you try posting on the AVS forum.Bunch of crt projector people who are very knowlegeable and someone may very well know your projector.

Good luck and let us know how things are progressing. Attach some pictures if you can.

let it run for several hours. sometimes those crt,s will come back not like new but will brighten up. steve

Lol let it run.... I can't really object to that.
As for new CRT's I'm guessing not any CRT will work. I've looked on ebay and found crts but they are never for this particular zenith. Or a zenith at all. Would any electrostatic tube work(And I know they probably won't)
And I will try not to look in it. I've only looked in 3 times for maybe a second or two just to check. I figured it was bad for your eyes. It's pretty much an extra bright tv focused on one spot. No more of that though!

I've posted on AVS and it seems they know how to change bulbs and fiddle with controls more than anything. I've got very few responses that actually led me anywhere but another website.

The yoke switching like some one mentioned, Lucky for me There is a sticker showing 4 ways to hook up about 8 connectors to achieve front floor and rear projection and I can't remember the rest. I'm going to try switching it to Front floor projection though.

And I really, really don't think this projector has any menus on it. The whole things seems to be very analogue.

G2 controls....? Are these controls controling voltages at the pins of the crt?

P.S. I've tried turning some knobs that were labelled for the green gun. I can't get it to go any brighter from any of the obvious controls. After playing with them I always set them back to what they originally were. And I never turn them to extremes.

Yes for the G2 question..

It really is hard to tell from the pictures you've attached, but in the first one,the board in the middle of the picture may have the screen and focus controls, but can't be certain. Each control will effect the individual crt.The green is always in the middle. Can you read any of the names of the controls?

From the picture you have firing onto the wall, it certainly looks like the green and blue guns are weak. If you want, try cutting out of cardboard a circle large enough to cover the face of the lenses.You only need 2 pieces. Then, cover two of the 3 lenses and see how much light you get.It's best to do in a really dark room.That projector uses 7" tubes and aren't very bright to begin with.

If AVS is of no help, you could always go the Curt Palme's web site and shoot him an email regarding the crt's...You'll need the model number of the Zenith you have and he may be able to cross reference it to replacement crt's...to be totally honest, you will most likely be looking at 3,given the fact they all are dim.This will give you an idea as to the costs you're up against. You also may have drive board issues, as has been suggested.

If you find the G2 controls, be cautious.Cranking them up can wipe out a crt.These are the controls that apply specific voltages to the crts.

Forgot to mention.This Zenith probably does not have a menu system.A lot of older projectors used analog pots that you use to set up geometry for each tube.That's why it's important to be able to turn off all light from the tubes except the one you are sizing.You always start with the green gun first and then the other two.Once you have them equal, then you go thru the convergence steps. There will usually be pots for each color and they will have name like hpos,vpos,hsiz,vsiz,skew,bow,lin,etc. See if you can find these anywhere.Typical place for them would be in the rear of the set with the cover removed.They should be all bunched together..so, you may see ghpos,rhpos,bhpos or something like that which would refer to green,red and blue horizontal position..Vpos would be the vertical pos and so on.

That is a very unusual projector, It looks like the crt's are round. And yeah it looks too old to have any digital controls. I wonder if those crt's were made by Zenith at their own plant. My Barco's and Bell&Howell use Clinton Electronics tubes that are rectangular. There is a place in Georgia that can rebuild projector crt's. The name is Video display Corp. in Georgia. I searched their website and most of the Zenith tubes run under $200 for rebuilds.

VDC is the one that rebuilds crts.I recall reading about VDC replacement for Electrohome projectors quite a few years ago. This is why I mentioned Curt Palme.He reconditions projectors and sells them and has (or had) a lot of crts that were parted out and he may have some info onth the ones that were used in this Zenith.He has used VDC rebuit tubes.
It would not be,IMO, worth it to buy rebuilt CRTs for this unit because they would cost more than you could probably pay for a decent working projector.These early Zeniths were just so so performers. I'm certain that he could find a Sony VPH-1251/1252 for under $200 these days and it would provide a decent start for someone who want to get their feet wet with CRT projectors.These Sonys use onscreen menu systems to adjust everything.

...

should I really try running this set for a couple hours?

Also would brightness invlove The HV lines? Cause if so I have something to say

Is it shorted? or arcing? yeah that could make a difference. What's happening with them? Logan

I have that SAME exact projector. Except it is labeled as VIP Mark 3 from layfayette.

I NEEEEEED to find a schematic on this thing somewhere.

The convergence board in these bad boys are poor. I was going to rewire the set with a digital convergence module, but i need to find a schematic.

Oh BTW, its a rare one, and yeap mine still plays. except the poor convergence that just wont correct very well.
Edit/Delete Message

Yes i know this projector inside and out. I'm the person to talk to about this projector. Its a very crappy design, and an extremely rare projector. Although they will play forever if you take care of them.

Your case is probably a open resistor in the feedback circuit off the splitter assembly, and the splitter assembly also known to go bad. (i had to unpot and rewind mine, as i never found a suitable replacement. and i WILL NOT DO THIS AGAIN. it was terrible).

The orientation and convergence setup is done on that little board in the middle of the unit. I am going to warn you that the convergence is piss poor on these particular projectors, and they are video grade only.

I was going to re-wire mine to use digital convergence, but I cannot find schematics/data on this particular set.

Also, the CRTs are round, and the glycol chamber is part of the tube. on mine, the blue tube glass cracked, (CRT is fine, still works) and the glycal leaked out. I had to get a new peice of glass cut for the chamber, dig out the silicon, and replace the fluid and redo the silicon seal.

One more thing: Your going to have to go through every capacitor in that set. I advise getting an ESR meter and adding that to your collection of electronics testing gear. it pays for itself in notime.

Ok, a set this old, the elecrolytics are going to dry up. I had to recap my entire video signal board before mine would even show a picture!. then while i was in there, i went ahead and did up the power supply and HV sweep modules. I found the picture framer board quite annoying, so i unhooked it.

I guess I am lucky, but all 3 CRTs are very strong in mine. Although, the red CRT appears to show a "raster with retrace" even with the filiments unlit and disconnected. and also some purplish blue is seen on the clear spot of the neck, so its probably getting gassy, however once the tube filiments heat up, picture is nice strong and crisp, so it does have some life left.

also its intriguing to know that theres another individual out there with this projector. ive been fighting a monologues battle with mine. hehe.

Well, that looks like the right kind of challenge for you JesusJones! Good luck...

If those are liquid cooled tubes could there be mold or fungus growing in the coolant? I know that was a problem with some rear projection sets. It would cause a major loss in brightness for that tube. The solution was to empty the coolant, then clean the front of the tube and the lens, then replace the coolant with new fluid.
By the way when you search for the tubes try searching for PRT's as well as CRT's. This was to distinguish them from regular picture tubes.

Bill R

Rudy...while I really applaud your intentions to get this projector to work, I am of the opinion that if you are able to get this working,the actual performance will probably be disapointing. Do not take my statement as a negative one..it's just from personal experience..they do not look very good (sorry mbates).

If your interest is just to find the problems and get it working, then more power to you.It would be a great learning experience. But, if you plan to use it for the purpose of watching a large image, you can do much better that this.

If you haven't checked out Videogon, give it a look..lot's of CRT projectors for very little money ( excluding shipping charges if that applies).

Here's an example of a fairly decent projector capable of higher scan rates than a video only projector.That means it can handle line doublers, progressive scan DVD,etc. where the one you have can only do video at 480i which means you'll see the scan line structure big time. Conversly,with one that scans at 31khz, you could play a progressive scan DVD player without seeing those lines...


http://cgi.videogon.com/cgi-bin/cl.p...851&class&3&4&

well if you got fungus growing in those tubes, all power to ya trying to change it. youll have to cut the CRT away from the manafold to even clean it out. it has a drain screw, but you still have to wash out the CRT.

Thank you every one.

And yes after I found out this projector was made in the first year Zenith began making these. I knew it would not be very great, but I thought it would just be fun to toy with. And if it did work half as well as I thought for 10$ it woulda been a steal.

I'm gonna check for mold. Mold would be a god send. (easy inexpensive fix)

Mbates14 You mentioned the splitter assembly. What part is this more specifically?

And I have seen "One" schematic for this projector, but you had to buy it. Other than that I have looked and looked(You probably have to) And it's impossible to find.
This is the page http://www.analogalley.com/m_zenith.htm
I didn't wanna pay for it. Just so i could be sent the wrong one.

And the HV goes to a splitter. Here at the splitter are some controls. (For each tube.)
From playing with them I have noticed they make the color brighter or dimmer.
There is Low medium and High jumper and then a vari pot to fine tune.
Blue and Red were set to medium. And green was set at high when I opened it.
This leads me to beleive the tube was most likely cranked up higher and higher till death(Shucks) (Or maybe there was just more and more mold!)
Also upon starting the unit during the nite I Noticed HV arcing to the frame.It was not intense and stopped after a second or two. But maybe this is a sign of something?

Oh and I got the picture right side up by changing the yoke pin connections. Now it's rightside up. No miracles there

Rudy

Well if you look down the lense while on, or taking a flashlight to it, it will be pretty evident.

I would take the 4 screws out of the lense from the manafold, and take a look that way. there we ill be a "gell like" substance on the face of the CRT glass manafold. its nothing to worry about, just a moisture sealant.


this way you can inspect the CRTs phosphor condition, along wiht fungus, etc etc.

if there is extreme fungus, its not a godsend. its harder than you think. you have to cut away all the silicon between the CRT and manafold to change the fluid. as IT IS all in one CRT, meant to be replaced as a whole assembly.

I dont even use mine anymore, it worked when i last put it up, I wanted to find something different, but i never could around my part of the globe. hehe. (im in cincinatti area).

and, oh yea. if you have to take the CRT apart, careful not to loose the plastic seats that fit between the glass and metal manafold, it holds the CRT a certain position away from the face of the glass.

Yea I'm in winnipeg Canada. Things here are hard to find and generally not cheap.
Garage sales are always the best bet for me.

You mentioned the splitter circuit if the gel was not full of mold?

The esr meter tests capacitor leakage or what? I looked it up only briefly. I might go buy one right now if it's that good

The schematic you want on the page has PV800P as the service #

And I don't think it's mold. Every crt through the lense looks the same. A nice grey colour. With red showing the most wear actually.

yea but if your HV is staying up, your splitter is fine.

I honestly think you need to get to all your capacitors.

Dick Smith ESR meter. you can get the kit, or buy the meter outright.

Ok I bought the new blue one. Looks kinda shabby compared to the black one but that's ok.

I think I paid only 70 or 80$ for it. Sound right to you?

yea thats around that price.

those tubes did not have coolant for cooling. there is a gel pad between the crt face and lens. thats not your problem.

yes it does. I can prove that to you.

there is a gel pad between the glass and lense, but there is fluid between the face of CRT and glass. Crack the glass by accident one time, youll see.