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#1
07-29-2020, 12:07 PM
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Oh nothing much, just an RCA DIMENSIA!!
Okay... Okay let me re enact when I first saw this TV sitting on the curb last night:
"What's this?"  "Oh, that is a lot of inputs... What the heck is this thing?"  (Click for full size) "Oh my god! I never thought I would find one of these!!" "Does it work?! Does it work?!"  ""OH MY GOD IT WORKS! IT WORKS IT WORKS IT WORKS!!" Okay... Okay... Okay... Let me just take a moment to think about the odds of finding what was probably the best consumer grade RCA TV that you could buy at the time. I don't think you could have gotten a better RCA TV, unless it was a commercial installation. You may be familiar with the ColorTrak 2000 TV's from RCA, well those were a derivative of the Dimensia.  Made in November 1987. If I understand my history correctly this was *just* before RCA was sold to Thomson. GE had acquired them, but didn't sell the TV division of RCA to Thomson until 1988. This makes this one of the last true RCA sets. Oh I have to get the back off of this! I have to see what it looks like!  My God... look at how clean it is inside!! There is hardly any dust! The HV anode lead hasn't grown fur on it! Either this TV was opened and cleaned regularly, which is amazing seeing as it looks like it was never opened before. Or... Or... Or... this is a low hour set!! I mean I plugged it in, turned it on, and the picture came right up! And it's on the default brightness and contrast settings! I have yet to try it with a signal, but even the snow on the screen looks bright and sharp! Gentlemen: I think I have found RCA's swan song. 
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#2
07-29-2020, 04:19 PM
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Quote:
There was a demo mode to that bad boy as well, something quite unusual for the 80s. I can't remember the key combination to push though.. Give me a day or so to think about that. Anyway, the CTC140 was probably the best analogue TV ever built from a picture standpoint, better than any variation of the 169 that replaced it (and there were some excellent 169s). Whereas the later 169s came in low end versions, all of the 140s were fabulous performers. They even made a 20" version. I can't think of any CRT TV that had the combination of detail, sharpness, smoothness, and lack of artifacts than the 140 had. The 140 was not trouble free however. The good news is that you won't need what I call "hard parts" (transmission term) like flybacks, yokes, drive transformers etc. Almost every 140 has connection issues on the small daughter board mounted upright behind the SMPS transformer. There is a thin air coil inductor and three rectifiers on that board, and the solder cracks causing intermittent shutdown and restart. If you get a spontaneous restart, look there first. There are some other issues that we won't talk about now. If that is a low hour TV, you probably will only deal with the daughter board solder connections (we had to solder them even in warranty). Enjoy. John
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#4
07-29-2020, 04:50 PM
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I have more pictures that I took but forgot to post, in part because my hands were shaking so much just from excitement.
A Dimensia has been something like my White Whale set, and to find this late 80's example with the 27" screen and comb filter, in this good of shape. I am still in shock. And it was like 8 or 10 houses down from where I live too! And the lady who threw it out told me it was her grandmother's TV, and that her grandmother meant to throw it out but missed trash day, so she took it home to throw it out, and I happened to find it! Okay then, so more pics:  Allllll those inputs and controls and adjustments...  So this is a CTC 140E chassis. Dunno what the E means but I would guess a later revision?  These are probably the best speakers I have ever seen in a 27 inch set. I hooked the TV up to a converter box and the picture is near flawless! Corner convergence is maybe a pixel or two off, but I don't want to mess with it. I don't think the chassis has ever been touched. It is all original and I do not want to mess with it. I mean if that solder issue with the daughterboard comes up I'll fix it of course, but this TV is so nice... I really don't want to molest it.
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#5
07-29-2020, 04:52 PM
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I do have one question though:
That SCART connector on it. I know it's not really SCART on this set, but can that be used as a video input? Meaning can I connect something like S-Video to this set to get the best possible picture?
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#7
07-29-2020, 10:51 PM
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Oh the 65 inch Smart TV in my living room, made in 2018 has very good sound as well. No sound bar or anything, it just has good internal speakers.
But I digress. I have had a chance to run the set and it's not as low hour as I thought. I do need to set the brightness up to about 3/4 to get a bright enough image. So the CRT has some hours on it. Also I don't think the set was run in a long time as the picture started out more shifted towards green with weak reds, but over the course of the hour that I ran it, the red balanced out. Also some of the front panel buttons were unresponsive at first, but as I pressed them, they started working again and now they work fine. I think the set just needs to be used, and given a G2 adjustment.
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#8
07-30-2020, 12:38 PM
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Soooo I'm wrong about it being a low hour set. I did a setup with a test pattern DVD and found out the drive controls are maxed out, and I have to max out the contrast to get the picture halfway acceptable.
I have some headroom on the G2 adjustment before I hit retrace lines, but the CRT is pretty tired. Still there is enough life left in it for me to see just how good the picture was, and I can't blame the owner. If I paid the 1987 equivalent of $3400 for this TV, I'd sure as hell use it for the next 30 years until the CRT got too weak to be acceptable. What amazes me is how clean the inside of the set is. Though I guess if you can afford a TV that expensive then you can also afford ionizers to keep dust out of the air. Wouldn't it be neat if I could get ahold of an A68ACC12X CRT? But I would settle for borrowing a CRT tester with a good rejuvenate function. A simple clean and balance (the lighter form of rejuvenate) would probably wake this CRT right up.
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#10
07-31-2020, 04:11 PM
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Nice catch ! I still like the CTC169 better but the 140's were more serviceable.
CRT looks super strong so I would not shoot the CRT. Just do a by the book set-up on it & enjoy. 73 Zeno  LFOD !
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#11
07-31-2020, 05:18 PM
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I can't tell, but the tube looks strong in your pic.
IIRC, the correct setup for the drive controls would have at least one at 100%, the other two adjusted for best grey scale at high contrast and brightness. The bias controls would normally be adjusted about half way give or take. These were never the brightest TVs, but they were bright enough to produce an accurate, not cartooney over drive pic that people today seem to love. There is a contrast preset pot someone on the board (orange towards the middle??). I used to turn them down a bit so customers didn't crank the crap out of the contrast. They were never perfectly focused in the corners either, but good enough. These were almost flat CRTs, but IIRC, RCA didn't use a modulated focus in the 140 as they did in later 169s (the higher end versions). If your grey scale is accurate and you can focus it sharply, the tube is probably fine. As for the E variant, RCA just added letters to differentiate the difference between all the models that used the same basic platform. Your E has a computer that no other RCA 140 had, and that is the Dimensia processor. IIRC, it's on it's own daughter board. Notice the RCA connector that says "control"? Other 140s didn't have it. That's unique to the E and the Dimensia series. Other variants would offer fewer AV jacks, different audio output ICs and associated components, or if it was a 20", would have a different flyback and other 20" specific components that only that variant would use, so the tech would use the schematic for the exact chassis. The later 169 variants were even more varied. Some had pix in pix, no pix in pix, or 12 picture pix in pix, one of several analogue and digital comb filters, one of five or six different audio sections, different deflection circuits depending on CRT etc. John
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#12
07-31-2020, 05:44 PM
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I would like a CRT tester to verify just how good the CRT really is... but what I do know is all 3 drives were set at max before I got the set, and I need all 3 bias controls set to max or near max. (The green seems to be the strongest gun)
With the contrast and drive controls maxed out, the grayscale is acceptable. I will try tweaking that contrast pot, see if it helps. I made a video on this set. You can see it in the thread here: http://www.videokarma.org/showthread...97#post3226397
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#13
07-31-2020, 07:19 PM
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IIRC you balance the grey scale to the strongest gun BUT its
been probably 15+ yrs ! In other words if G is dominant leave it all the way down & bring up the R & B for grey scale. I should have the Sams & will look tomorrow. If the process is short enuf I will post it, probably abbreviated... By the book its not as simple as most sets but you can eye ball it just about as good. 73 Zeno LFOD !
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#15
07-31-2020, 09:07 PM
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It's possible a ham and egger screwed with the controls. There is a way to put that TV in the service mode to get the line for setting up the biases. They should not be near 100 percent. At least one drive should be. I probably tossed the field service training manuals but I'll check tomorrow morning when I get to work. John
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