Trinitron Sharpness Expectations - Mac CC

[atariangamer]

Good day, all! A few years back I managed to score a Color Classic and did the 640x480 mod with Mystic logic board upgrades. I think it has some cap issues (has to be plugged in for 20 minutes before it'll respond to the power button on the keyboard), but I've been hesitant to pursue it because the display, while vibrant and bright, is incredibly blurry.

I've tried doing some small adjustments by the book, using the Display Utility, but the text has such soft edges, and the single pixel wide text in Finder filenames just makes it difficult to look at. I know this is a very small screen to be cramming VGA into, but everyone touted how sharp and amazing the Color Classic display is...

Last night, I pulled it out of storage and warmed it up, got it running again, and noticed that the rings on the CRT neck were all out of place according to the glue and marker lines on it. I then did a bit of work on the adjustments again. By the book I turned the background adjustments all down, and then turned the drives and subcontrast adjustments. With just the red showing, the display was dim and only red tinted, but it was surprisingly clear. More so than I had seen it the entire time I've owned it. But the more I adjusted to follow the service book, and the more color I added, the more blurry the picture became.

~

All this to ask: anyone with a VGA modded CC, is the Trinitron in the CC still sharp and clear? Or is it a little soft around the edges? I can't find a great picture of the tube up close to know what to expect. I love the machine and love using it, but the eye strain is quite noticeable compared to other CRTs I've used in the past.

And if it's expected to be sharp and clear... would a recap help? Or do I just need to locate some CRT equipment and do a proper calibration on the tube independent of the analog board?

 

[Byrd]

The CC CRT was never super sharp and amazing to begin with, even at stock resolution. The 640 x 480 mod does show dot pitch and refresh rate limitations as well. I'd suspect if yours had loose rings, it might have been dropped and the mesh has been dislodged slightly. You might need to adjust the rings out of spec and see if you can get better colour purity and convergence that way.

 

[atariangamer]

The CC CRT was never super sharp and amazing to begin with, even at stock resolution.

That is what I am discovering... I found another Sony M23 tube from a logic analyzer module, and the spec sheet on it only advised it for ~325 lines. Close enough for the stock resolution, but a stretch for the 480. I just took delivery of a Performa 475 and its 14" monitor, and the difference in clarity is astonishing.

I'd suspect if yours had loose rings, it might have been dropped and the mesh has been dislodged slightly.

Fair point. I know it wasn't in the best of conditions when I received it. A colleague from work is currently looking at the analog board and testing its capacitors, when I get that all back and it starts working more reliably, I'll try adjusting it some more.

Thank you!

 

[chiptripper]

Yeah the 640 x 480 mod just makes for a blurry display in my experience. It’s noticeable enough to me that I tend to eschew it when I build a Mystic, for better or worse.

I’d test with an unmodified AB, if you have one, if it’s still blurry you may have a flaw in your display or AB. Caps can cause display troubles on these boards, fwiw.

 

[ymk]

The focus seems about right on mine. 640x480 opens up a whole world of software.

 

[pizzigri]

I seem to recall that this Trinitron tube was originally built as a monitor for Sony broadcast cameras (the big things in studios and sports events of the era) and medical equipment; it is rated - stil if I am not mistaken - for NTSC and PAL /Secam video. Visible lines are respectively 480 and 576, both interlaced, and both with horizontal res of 720 dots.
Since the highest PAL standard calls for 625 total lines (not all visible) sent out in alternating half frames, and the monitor paints only half the total resolution at any moment, it never exceeds the 325 lines specified.
However, it is for “video”, so it would be incredibly crisp with say Ultrasound diagnostics or studio interviews, So pushing it to 480 non interlaced, progressive video with one line res text is really…. “Pushing it”.

 

[ymk]

So pushing it to 480 non interlaced, progressive video with one line res text is really…. “Pushing it”.

Why? The lines occupy about the same position on the screen whether they're drawn every frame or every other.

If the grille is fine enough for 480i, it should work just as well for 480p.

 

[pizzigri]

I totally agree on paper, in practice while this is almost always the case for motion video TV (you know, with all the "bleed in" "motion blur" etc and all those effects that made us believe or perceive a higher resolution of moving images was displayed on screen), it is definitely not always the case for computer graphics... and while using a CRT in spec will give expected performance, out of spec said CRT may yield wildly different results. Apple did use the Sony CRT (almost) within spec in the CC.
I also had a CC that had amazing definition, many years back with the HiRes mod. At least, I remember it was amazing - 20 years can sort of rose tint your memories. Today, both of my CC - one Takky and a Mystic were unsatisfactory.
The Takky suffered a AB failure some time ago and since transformed into a LCD, and I dialed back the CC to 512 (actually tricked to 560) x 384.
IMHO, of course.