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  #16  
Old 01-24-2017, 02:09 PM
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Kirk: Thank you.

Ben: Thanks for the tip. Never heard of it, checked their website, looks like an excellent product. I will give it a try.
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  #17  
Old 01-24-2017, 02:55 PM
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Brasso tends to leave a mottled appearance to the brass, only visible once the lacquer is on it. If you use Brasso before silver plating, sometimes the plating process will fail; you'll get a blotchy uneven finish no matter how you try to clean the Brasso residue. I've never had either problem with the MAAS. You're mileage may vary of course.
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Old 01-24-2017, 04:21 PM
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Quote:
Originally Posted by benman94 View Post
etype2,
You might consider Bob's method of removing the old lacquer, but instead of using Brasso to polish the brass, use MAAS polish. I do brass instrument repair and restoration (I specialize in higher end pre-war Conns) and MAAS is the polish I always use before either silver plating or hitting the horn with new nitrocellulose lacquer.
Would that be good for bronze as well? The handle on my Heathkit GR-370 had the most crap I've ever seen on decorative hardware, bar none. It's mostly gone now, but the hardware is still badly tarnished.
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Old 01-24-2017, 04:28 PM
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Yes. I've used MAAS on bronze with great success, and even on pure copper (a Conn 12B with the "Coprion" type bell). It works great on silver too, but electrolytic cleaning is always a better first line of attack with silver. At least with electrolytic cleaning you aren't removing any of the underlying plating.
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  #20  
Old 01-27-2017, 01:33 AM
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Here is one more screenshot from my restored RCA 21CT55, captured from last nights tribute program to Mary Tyler Moore who passed away on January 25, 2017. Her show was a favorite of mine which ran from 1970 to 1977.

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Last edited by etype2; 01-27-2017 at 04:06 AM. Reason: Typo
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  #21  
Old 01-27-2017, 05:15 AM
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beautiful image and such a lovely smile... vale MTM ....
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  #22  
Old 01-27-2017, 03:22 PM
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couldnt have found a better face to look at.beautiful lady and i very nice image on that set.
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  #23  
Old 01-31-2017, 05:25 AM
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Thanks, Mary Tyler Moore will be missed.

Tomcomm: you asked for larger screenshots and a comparison to a computer screenshot. I'm not currently using a computer, just an iPad Air first generation. I have a 2012 Sharp Quatron 70 inch LCD TV/Monitor with full array LED backlighting. One notable feature is that it has 25% more pixels because of the yellow pixel. We had the set calibrated to ISF (Image Science Foundation) Rec. 709 standard three months after purchase in March, 2012. You can see the calibration charts on the "4K" page of my website. I estimate the set has over 29K hours on it. The first photo was captured with an iPhone 6 Plus of the Miss Universe contestant representing France and won the competition on this Sharp monitor. Fox broadcasts 720P not 1080i

1.

2. The second photo is the same frame captured with the same phone off my RCA 21CT55. This photo was cropped to remove excess boarders.



3. The third photo is the same image as photo 2, but captured with the iPhone 6 Plus off the Sharp monitor by Apple mirroring.



4. The fourth photo is the same image as numbers 2 and 3 captured as a screenshot from my iPad Air formatted to it's 9.7 inch Retina display. When the iPad Air first came out, Display Mate website ran a test and declared it "the most accurate mobile display" at that time.



I don't know how "scientific this test is, but one thing for sure is you can see how much of the image is lost on a roundie CRT. I'm still not satisfied with the color on my 21CT55 and further "tweaking" is required.

It appears that the mirrored image lost image detail, etc. but I can tell you the Sharp monitor is very accurate. (See the calibration charts on my "4K" page.) https://visions4netjournal.com/4k/

Continuing .....
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Last edited by etype2; 01-31-2017 at 06:39 AM.
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Old 01-31-2017, 10:19 AM
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I'm not sure if it's an artifact of the camera, my vision, or both, but I see very little color in the lips on Ms. France.
I also don't see much green in the previous screenshots, but that could be an artifact between the camera, my display, and my eyes.
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  #25  
Old 01-31-2017, 11:48 AM
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Ben,

Yes, that bothers me. On all the screenshots so far, women's lipstick just will not display well. The red is there though. You see it in her hair. I have a screenshot of JoAnne Worley from the Laugh In show in 1969 and her bright red feather boa displays with good red, but it doesn't pop.

On the pattern generator, all three colors look good. More adjusrtment with the color gain controls? Mike said the all three guns tested strong, just not new.
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  #26  
Old 01-31-2017, 12:37 PM
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Quote:
Originally Posted by etype2 View Post
Ben,

Yes, that bothers me. On all the screenshots so far, women's lipstick just will not display well. The red is there though. You see it in her hair. I have a screenshot of JoAnne Worley from the Laugh In show in 1969 and her bright red feather boa displays with good red, but it doesn't pop.

On the pattern generator, all three colors look good. More adjusrtment with the color gain controls? Mike said the all three guns tested strong, just not new.
Don't expect lipstick or other really bright red things to look right in
real scenes.

Several things to check:

1) is your modulator being overdriven? That will do it. Step 2) checks this.

2) check B&W step patterns on all three guns ... be sure the red
one is not seriously overdriven. This will also check 1). I suggest lots
(like 30) of steps.

3) check the fine tuning and IF response with a full-screen horizontal
chirp test (e.g. Digital Video Essentials), with the color control all the way down.
There should not be a dark area where the chirp goes into
the color region (starting at say 2.2 MHz) . If adjustment of fine tuning does not get
a sharp picture (i.e. down more more than 25% at 3 MHz) , good amount of color
(on a color picture), and lack of the dark area, you probably need a full RF-IF alignment.

4) check the setting of the R-Y drive pot by examining the
R-G-B CRT grid waveforms with a scope, at low contrast settings, using
normal color bars. The should show all the bars at only two levels.
Adjust the R-Y pot, color level, and hue until its as good as possible on all three.

5) check adjust contrast and brightness for proper bar appearance
being sure that the red gun is just barely clipping.

6) recheck the gray step pattern to be sure it is uniform color. If
not, readjust screen and video gains. Be sure to check the red screen pot ...
all the way CW may not be best, run through the whole range. Then recheck 5).

I just did this yesterday on my CT-100 and found 6 to be a problem.
The gamma is too high on these CRTs and you may be unable to get
good bright reds and good scene visibility in dark scenes at the same time.

4) can't be reliably done by eye ... you may be setting with too much red clip.
You need a scope.

Repeat until you understand what is going on.

Doug McDonald

Last edited by dtvmcdonald; 01-31-2017 at 12:41 PM.
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  #27  
Old 01-31-2017, 01:13 PM
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Doug,

1. Not using a modulator, but I plan on purchasing a very good quality modulator, maybe even a pro model. I suspect that my $50. digital converter is degrading the image. I say this because when we were testing on Mike's setup with modulator and DVD the images looked cleaner. I see "video noise" for lack of understanding of what I'm seeing. Also there is a faint vertical band in the center of the screen only visable in dark scenes. The band was not present with the DVD/modulator.

3. We did do a full IF alignment. I think that is why the this 21CT55 displays very good detail. I have a copy of the Video Essentials disk.

I suspect the red gun is being driven to high.

In the end, based on what we saw with the modulator/DVD setup on the bench and what we see with the digital converter now, our next step will be to purchase a high quality modulator so I can view DVD's on this set and go from there. I'm very happy with the image detail though.

Thank you for the excellent testing recommendations. We will follow through.
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  #28  
Old 01-31-2017, 01:42 PM
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The Blonder-Tongue BAVM single-channel models are just fine. Yes,
the -SAW ones are better than the -z ones but I can't tell the difference
on any of my TVs. They are very cheap on ebay .. you can buy two or three.

And ... compared to the "agile" ones they run cool as watermelons.
The agile ones run very hot.
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  #29  
Old 02-01-2017, 07:10 PM
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My Miniature 3 inch TV

etype 2 I’m very much impressed with your Miniature TV write-up. I was
repairing TVs starting in the seventh grade and bought a 3 inch Pilot TV-37
in 1951 for use as a portable test set on service calls, which my Mom drove
me to. For a junior high school science fair in 1952 I cut the chassis width
almost in half and folded it over to make the “Worlds Smallest TV”, or so
I thought! I still have it in it's crude cabinet and it still works, maybe?

The cabinet modifications of my 21CT55 to make it fit into my new tiny lab
was no big challenge. I replaced the weak 21AXP22 with a 21FBP22A
and made it a composite baseband video only monitor only.
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  #30  
Old 02-01-2017, 08:13 PM
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Doug: Sounds like you see no difference in video quality between the two modulators. Can the Saw models be adjusted for over modulation?

Tom: Got it, you went for the purest signal to the television.

I got started with crystal radios in 1956, 9 years old, then with some help from my genius neighbor 3 years older then myself and already had a radio operators license, we got an old junker vertical console working. It was dumped in the back of a neighborhood TV repair shop. I asked if I could have it and he said it was junk but go ahead and take it. He helped me lift into my coaster wagon.

About the micros, thanks. A lot of them were bought new back in the day. I envite you to send me your favorite television's/projects. I will post photos and your information on my "Viewers Television's" page. The envitation is open to all who reads this.
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