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For the same brightness (white point when the screen is all white) and the same dither pattern (let's say 50% gray), my Macintosh SE CRT produces darker intensity than my other compact Macs (an SE/30 and a Plus). I use my Macs for graphic art, and I have trouble making dithered grays look consistent across the computers. I could almost describe this issue as a difference in the dot pitch of the pixels, i.e. the distance between the edges of a discretely lit pixel. Is there some component on the analog board or CRT assembly I could replace to adjust this?

 

Since I use the SE as a daily driver for art (because I have an ADB Wacom tablet), I was thinking of replacing its CRT with the Plus'. Are they compatible enough for this to be an easy switch? I know it's sad to deprecate the Plus this way... :(

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Posted (edited)
21 hours ago, nonzero said:

Is there some component on the analog board or CRT assembly I could replace to adjust this?


Someone who is more 'expert' on CRTs/analog boards will be along in due course I'm sure, but I would say these symptoms indicate a worn-out CRT. They all get to a point, with age, where they just won't perform as they once did. I have one that is *much* darker than it should be, even after adjustment/recapping the analog board.

One thing you may also want to try, just to rule it out, is run the Mac SE from the analog board from your SE/30 - they are the same board, so a straight swap is possible and a good way to rule out problems with your SE board.

The CRTs between the Plus and SE are compatible, yes. Alternatively, these 9" CRTs appear on eBay now and again, so look out for one if you don't want to deprecate your Plus.

Edited by joshc
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Have you cracked open your SE and adjusted the brightness, focus dials - there are also test patterns to properly calibrate the size of the image displayed.

 

My experience on "worn" CRTs is they often dim displaying bright images, and if high hours almost invariably have some sort of screen burn in.

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Posted (edited)

Yes, that's about the size of it. Like @Byrd said, generally, if adjusting the Cut-off trimpot on the analog board (with the brightness dial on the front set at roughly middle) doesn't make a marked difference in screen brightness, it's time for a new CRT. Just be sure to use a plastic trimmer tool and not a metal flathead screwdriver...

Edit: there are better guides out there for adjusting the CRT "correctly" which I'm probably not illuminating here. But I like to set the front knob/wheel to roughly the middle and adjust the 'Cut-off' to what would be "nominal" for my eyes. There's probably a tool that was used from factory to ensure some homogeny with the product, but anymore I just go by what "feels" right to my eyes, which is probably not as bright.

But as a rule of thumb, the brighter it is, the less longevity it will have... or whatever that BladeRunner quote is :lol: 
image.png.ec0812f47975a49d4da2ac37394d36d9.png

Edited by jessenator
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On 3/7/2021 at 10:12 AM, nonzero said:

I was thinking of replacing its CRT with the Plus'. Are they compatible enough for this to be an easy switch? I know it's sad to deprecate the Plus this way...

 

If I remember correctly, all the compact Mac CRTs are cross-compatible up to the mark 2 classic and the classic II, and those two can be made to work but it is a pain.

 

These CRTs aren't particularly rare at this stage (I've got a couple off eBay in the last few years, and I wasn't looking really hard), and given the cost-benefit ratio, they're quite a good thing to keep a spare of.

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23 hours ago, cheesestraws said:

If I remember correctly, all the compact Mac CRTs are cross-compatible up to the mark 2 classic and the classic II, and those two can be made to work but it is a pain.

 

^^ I agree—stick to this if you look at a CRT swap, based on my own experiences of CRT swapping..

 

Scott Baret outlines the finer details as to 'why' in this thread if you're interested, @nonzero:

 

I lucked out when I bought my Classic: it had the "Type A" yoke connector on it, and that's really what is critical: the connector type. You can literally use any 9" monochrome CRT(ube) from the era. If you do go with a non-Macintosh one, (or a tube from a late model Classic or a Classic II) you'll have to do some potentially dangerous electrical parts surgery (and possibly some irritating mounting hardware augmentation) to swap whatever it has on it with the yoke from your SE.

 

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