CRT heaters go dim when set is off and brighten when powering on...

You're not likely to find a TV shop that will work on this unless you can find an older TV shop that is hungry and does not have a huge workload. Most shops won't touch anything over 10 years old and many won't touch any CRT set. I recently fixed a solid state RCA console stereo for a guy who had been trying to have it fixed for 15 years. All he got from any of the shops was "it's too old, throw it out" or "we can't get parts". It needed a complete electrolytic recap and I had no problem getting the caps. It's just that when a shop is quick to say that they can't get parts, that means they don't want to work on it. On one side of the coin, I can see where they're coming from. Given the high volume of work they do, they don't want to be tied to something that could take a long time to fix properly and they don't want to become married to an old piece of equipment that the owner keeps bringing back every time it develops a new problem, expecting a free repair. From my point of view, I think that if the customer wants it fixed and is willing to pay for it; then, I should do what I can to help them.

Here are pics of the chassis

And a few more

so what was the pro's of the works in a drawer? seems to me a bit crowded.

maybe the idea was you could service a module with out pulling the tv back from the wall and having to remove the back?

for you guys that actually worked on these, how did that work out in the field?

Ok now I'm trying to locate a CRT Tester/Rejuvinator with the right adapters. I'm looking at a couple of Sencore CR70. with the CR70 does anyone know what adapter will work for this set? the Picture tube number is 25ZP22

I don't know about the Sencore; but, if you get a B&K 467, 470, 480, or 490, the correct adapter for that tube is CR3.

I found a Sencore CR70 with all adapters on Ebay, most auctions say AS IS deal, and has not been tested other than powering up. Now how reliable are these things?

Hmmm no tubes.

I remember when we started working on these sets with the modules. For a time, we had a load of new modules and could repair the sets in no time at all. After replacing a few, we figured out what was going bad on the OEM modules, and repaired them ourselves. I never had a case where I went to the customers home, popped out the chassis, and replaced the bad module, collected the $$$ and left. Of course, we weren't a Motorola dealer, and these sets were 6-8 years old when I came along.

I'll bet that a new CRT would make this set shine again. Check out the cam switch first.

Fellow tv collector. What is the EIA number on that CRT? IT should above the type number. If it's 836 or 101 forget it. It's automatically bad. Also clean up that crummy looking anode connector to minimize corona leakage.

EIA is 185

my buddy has one of these quasars.it has a nicely made cabinet but came with one of those funky crts.the orange red,etc.he changed it out with a rebuilt sylvania tube and it really looks good.very nice swap and other than the crts,those quasar sets were pretty well made.i think those crts were in some of the lower level cabinets.the mid 70s were good performers with nice sharp crts.good luck on this

The EIA number for Motorola was 185. I remember reading somewhere that Motorola was setting up there own production line for CRT's. Big mistake. They're the only ones that made the 21GFP22, which was also a lousy tube. Just wait for another CRT before proceeding with other repairs. I'll be well worth the wait. Dave.

So your saying a Rejuvinator will not fix this tube?

Also if i do need to locate another Tube, where would i be able to find one?

I'm sure Video Display Corp. will have a sub for this tube; or, I'm sure most any 23V delta gun CRT from the '70's would work (someone please confirm this). If you could find a '70's era Zenith 23" console that was beat up, you could probably use the CRT out of it. Those Zenith tubes seem to hold up the best. I think most '60's and '70's rectangular 25-P22's and the later 23V tubes will interchange as long as they are of the delta gun type and the mounting is correct.

I'm sure a rejuvenator will help your tube; but, the fix will not be permanent. It could last anywhere between a day and a year or more; but, a good CRT is the only "real" fix.

Yes, I think that is correct about those 23V tubes being compatible. With a little patience one will turn up, either new/used/rebuilt.

I have a few works-in-a-drawer chassis tucked away. Probably some parts missing, but if somebody is ever looking for something...let me know. Eventually they'll get tossed. (it will be about a week before I find a Quasar myself!)

Here's a picture of the set on after cleaning most of the controls and the picture tube connections

I was wrong again! Second time this year. The picture looks very respectable. Fine picture for a tube that was never rejuvenated.

In the pictures the tube looks fine, the color is set to where anymore increased color will cause much more bleeding. If you look at the pictures you can see the colors on the screen bleeding a little. Also the full brightness, in the pictures look fine but in person the tube can be a little brighter.. I'm waiting on my Sencore CR70 Rejuvinator i purchased off ebay.. I hope it helps..

tvcollector, I'm wondering if you are anywhere near me. These sets were just being introduced when I got out of school and joined Motorola, and it would be a kick to see one operating in person again.

Well I'm all the way in South Florida, West Palm Beach to be exact... If your in IL we are far apart... It would be nice if there was one local from me, but i seriously doubt it..

Nothing has been done to this set other than cleaning, so everything is working off original parts even all the caps, transistors etc. may have been serviced in it's life time so a few components may have been replaced at one time.. I don't know how the caps hold up or if needing to be recapped..

Yep, in IL as my location says. Well, good to see that set running, anyway. It has some unique chroma circuits developed by Motorola's Chief Scientist at the time, Norm Parker.

I received my Sencore CR70. I've been testing and did a little bit of restoration. Now when i do the Emissions test it reads good or bad depending on the setting of the cutoff control.. All the way down is bad, in the middle (up/Down) reads into the lower part of good, and all the way up reads in the middle part of good.. I did the auto restore and then the manual 1 restore. I don't see much of a different in the picture.. The shorts test reads good, tracking also reads good.. any input would be appreciated.

I'd love to hear more about those chroma circuits, old_tv_nut... Stories like those, about yesteryear's innovations, always fascinate me.

BTW, that's a great set.... Don't think the c.r.t. looks half bad, to be honest.

The cut off is supposed to be set so the needle is in the cut off range, then you do the emissons test with out moving the cutoff.

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ok that was something i was not doing, i must have missed that part in the manual. I did this test on a 1976 Sanyo set that has a not so bright picture that look to be the green is a little too much, but the test on all three guns passed very good, and the cut off is set in the range with the knob three quarters of the way to get to the cutoff range, which i don't know if that means anything. I'm guessing more than likely there are problems in the circuit on this TV and the Motorola Quasar. I also tried the Motorola Quasar again setting the cut off and all three guns are well into the good range, with the cutoff setting with the knob being pass three quarters of the way..

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Well i hope the tester is working properly, i spent $125 on it and that was the as is price

as long as you can get the cut off in the range you are good to go, regardless of the setting. Sounds like your CRT is fine, I would not recommend any more rejuv attempts to make anything better.

As others have said, a CRT can test very poorly and still produce a watchable pic, no doubt less than perfect, but there are a lot of adjustments that can be set to make a otherwise weak tube look ok.

case in point, a zenith I picked up some time ago, it had a tube brightner on it which I removed, the red gun is weak. However after a few minutes the red picks up so its important to let things warm up before any adjustments.

Second adj drives and screens you can compensate to some degree for diff in guns, tracking may not be great but if you are not fiddling with the brighness then it really does not mater, set it up for a low light level and leave it there. Dont for get to set the focus, again it is optimized for the brightness setting.

bottom line is if one gun is weak It can look ok, not great but ok. But it sounds like your CRT is not bad.

I've tested two other sets.

My 1980 Quasar which when i brought home had a bright red picture. I had adjusted the levels to get a equal grayscale. Now i just did a test on it, the meter in the emissions test went into the good, but than slowly went into about three quarters of the way into the bad. Now i tested each gun and all were equally in the same bad range. I've noticed that when testing 4 others, the meter barley moves (or not at all) when testing each gun. I did a manual restore and all three guns are now in the middle good. I did color tracking and both shorts and all are good. I plugged in the set and was thinking ok the tube was restored a little now, so now when i see the picture the colors will be off and I'll probably have to adjust the red, green and blue on the picture tube circuit board to equal to a rejuvenated tube. Tv came on and the pictured looked the same..


Set two is a portable 1978 Panasonic. Which also has the same problem with the color. This one i tried to adjust the equal the grayscale and can't. But the bright picture looks good on this set, but when i turn down the bright the picture becomes a blue tent. I just now tested the tube and everything is well into the good range.

Now question is? is my CR70 working right? or more than likely on the 70's and 80s model sets the circuits begin faltering most of the time and not the picture tube?

Ok -

One of Norm Parker's inventions was the idea of directly demodulating the composite video (containing luma with chroma subcarrier riding on it) into red, green, or blue. Now, you can't do this correctly without some manipulation, because, unlike the RCA dot-seqential system, the NTSC subcarrier has the wrong amplitudes of R-Y, G-Y and B-Y components.

In the NTSC transmitter, B-Y is divided by 2.03 and R-Y is divided by 1.14 before modulating the subcarrier (actually, the equivalent factors are in the formulas for the I and Q signals). Also, the luma signal consists of .3 R + .59G + .11B instead of .33 R + .33 G + .33 B as they are for dot sequential. So, direct demodulation gets the colors wrong. It's necessary to adjust the amount of chroma signal going into each color channel. R-Y needs a boost, B-Y needs an even stronger boost, and there is too much G-Y, (because there's already a lot of G in the luma) so G-Y needs attenuation.

What Moto did in these discrete diode demods is to make the luma be a common-mode signal for three demods, and the chroma a differential mode, with the required amplitude for each. So, all three demods have their required chroma floating up and down on the luma signal. At the output of the demods you now have the sum of luma and a demodulated color difference, that is, each one puts out R, G, or B directly.

When they later went to an IC demod, they used the same principle to put a luma current in common mode into the bottom of each differential mode chroma demod, getting R, G, and B as outputs.

Norm also patented a method to restore the upper I sideband before demodulating on the R-Y, G-Y, and B-Y axes, but this was deemed too complex to put in a set design, especially before ICs.
So, the set ended up with equiband direct R,G,B demods.

By the way, when I say "Norm invented" I mean that he developed the theory and some ideas of implementation, but there were others who worked on various ways to realize the implied functions.

Edit: fixed the B-Y and R-Y factors (had them reversed)

Gees, no one has any input on my last post?

difficult to compare the results of tests on 2 different crt's

for what it is worth, i have never been a fan of crt testers and cleaning/rejuv for any color crt - just too many variables - delta gun/inline/age of tube/ et cetera
it is usually pretty obvious when a color crt is reaching the end of its usefulness - many b/w crt will test poorly and display a very nice pic - same with color crt's

and for what it is worth - i am a believer that if you tested a single crt with five different crt testers you would come up with 5 different sets of readings

the last set of pics. you posted looked good - can you post some screen shots?

My opinion:

1) If the tracking is good, it's good, although the tube may be on the weak side
2) If the tube tests good, it's good, although the tracking (cutoff or G2's) in your set may be misadjusted (causing blue shadows)

Now, if you got a set where one gun could not be adjusted and it tested different from the others, your tester would be telling you that the problem was the tube and not the adjustment. You don't have that in either case you mentioned.

For case (1) you just have a warning that the tube that is giving acceptable tracking now may be on the way out, but there is no need to panic until you see some degradation in the picture.

For case (2) you are seeing that the tube is probably just fine and therefore you should look for your problem in the circuitry.

ok, thanks for the input.. I just wanted to make sure the tester working the way it should.. I'll post more screen pics of the Motorola later, or you wanting other sets pics?