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Fun with colour on my SE/30

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I've been scrounging parts for a while now to somehow upgrade an SE/30 to a colour screen. I finally started piecing it together:

 

PSX_20190305_215204.thumb.jpg.09b2d1592438d4ebacbe6eb030c0ee2c.jpg

 

The Mac has a RasterOps ColorBoard 264 in its PDS slot, and I've connected it to a VGA controller via a DB-15 to VGA adapter. Thankfully the VGA controller supports the 65hz refresh rate that the RasterOps card outputs.

 

The star of the show, however, is the LCD panel I managed to find. It's an NEC 8.4" NL6448BC26-27, with a native 640x480 resolution and LED backlight. The contrast ratio is perfect, with the blackest blacks and beautiful clarity.

 

I've actually got a dead CRT tube lying around, so at some point I'm going to attempt to depressurise it and cut it open!! I've watched enough YouTube videos on the process to hopefully not seriously mame myself.

 

Then I will attempt to mount the LCD behind the curved glass. Watch this space.

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I have a few of those NEC panels, but they were all CCFL, and I had an 8.4" long ago, only ones I have now are around 10" 

 

They are all 90s TFT panels. 

 

I am shocked that a generic LCD controller would actually run that display, most of those older displays were a very early parallel standard with not enough RGB color bits to do anything. 

Edited by techknight

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2 hours ago, techknight said:

I am shocked that a generic LCD controller would actually run that display, most of those older displays were a very early parallel standard with not enough RGB color bits to do anything.

I believe the panel I'm using was released in 2012 - well according to the spec sheet anyway. 

 

I had to hunt around for the correct LCD controller that listed this panel as compatible. The panel has an LVDS interface, and I also needed to source an inverter board for the LED backlight.

 

At first I had issues with all the colours being scrambled, but then the supplier of the LCD controller showed me how to change the "LVDS mapping" via a hidden menu in the on screen display. The different mapping resolved the issue.

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Love this project, been wanting to do this exact thing myself. Can you link to where you got parts? Looks like those LCDs go for $160+ on ebay.

 

I was looking at doing this with Adafruit's 9.7" display (basically the iPad Retina display), since 2048x1536 would be high enough res to be able to upsample a few different resolutions without bad artifacts. But, that relies a lot on a magical third board that could do analog->DisplayPort, plus even more difficult driving it at >60hz. This seems to solve that with a modern LCD.

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Nice project. Is putting an LCD behind tube glass a thing? Just wondering if it has been proven out already since it seems like the image quality would be affected by the non-coupled glass-panel interfaces. But I like the goal of trying to emulate the original look of the curved glass since the projects with just a color flat panel don't look quite right.

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29 minutes ago, tt said:

Is putting an LCD behind tube glass a thing?

It's been done before here:

 

Seems to look OK?

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Might be OK... I wish that demo had a white background. I was imagining it to be like this arcade screen (on the left) with the CRT behind a front glass/plexi.

 

 

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3 hours ago, nickpunt said:

Can you link to where you got parts? Looks like those LCDs go for $160+ on ebay.

I got everything off eBay, and yes the LCD was not cheap! It was certainly a big risk when I bought it.

 

There are Mitsubishi panels that are much cheaper, but from my reading of specs their luminance & contrast ratio are not as good (although I'd like to test this one day):

 

https://www.ebay.com/p/MITSUBISHI-LCD-Display-8-4-Inch-Aa084vc03-640-480/1145844889

 

The Mitsubishi panels are CCFL backlit, but I believe you can quite easily upgrade them to an LED backlight - might be a cheaper option.

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I'm idly curious about LED backlight sheet and whether the can be cut down to size or not. If they have the power and ground on two layers with connections in parallel to the LED layer, then it should be easy enough to retrofit any LCD panel? The second question would be power requirements and whether or not the olde schoole CCFL inverter in a PowerBook could be resistor limited to LED requirements?

 

 

320px-Lcd-led.svg.png

 

http://www.iitk.ac.in/asid06/proceedings/papers/TC2_1-I.pdf

 

I tore a 17" Display I was recycling apart to harvest the stereo speakers and the backlight sheet works fine on its own. So now I have a 17" light box, recycling only the LCD bits and stand. Takes up less cubic, but the CarlinStuffCount remains the same. Oh well.

____________________________________________________________________________

 

Back on topic: IIRC the one project I saw with a cut down CRT face had significant dimming due to tint of class or coatings. I bough a still unused wet tile saw for the project about ten years ago. :/

Edited by Trash80toHP_Mini
Apparently I can no longer typel ;-/

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You could also spray the front CRT Glass with a rear projection paint, and use a micro LED projector with a mirror in the back to extend the throw-distance. It would give it the curved look. now THAT would be cool...

Edited by techknight

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3 hours ago, techknight said:

You could also spray the front CRT Glass with a rear projection paint, and use a micro LED projector with a mirror in the back to extend the throw-distance

What a creative idea! I'm really curious to know how this would turn out - you might even be able to mount all the components inside the original tube?! (perfect for all those clear Macs about to hit the market :P)

 

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@Trash80toHP_Mini wow great job! I didn't read the entire thread in detail, but from your experience, do you think you could get an acceptable picture projected onto the back of the CRT glass?

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I don't want to re-rail the thread and I'm sure that this question has been thought about before.

Would the monitor from a Colour Classic fit and work in an SE/30?

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27 minutes ago, ArmorAlley said:

Would the monitor from a Colour Classic fit and work in an SE/30?

In a word, No, unfortunately. The Colour Classic CRT is much bigger than the original B&W ones. I think there would also be issues with the analog circuitry required, and also the shape of the glass on the front.

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@antsprojected image should be sharp as a tack. I never got to the optical bench setup and tests or cutting the CRT because I couldn't get the TEMPOtrio card to work with the 6500 board. Recent threads have proven I'll need to switch to a 6400 board for the hack do to incompatibility, so I'm thinking about resurrecting it at some point.

 

Etching creme on the inner surface of the CRT is the plan for the  back projection screen. Hopefully it'll look like the ground glass focusing screen surface in one of my old Nikon SLRs. Because the surface of the CRT is curved, the distances from projection lens to screen are variable. That's where the optical bench testing and Wide Angle Auxiliary Lens come into play. Plane of focus needs to be warped to align with distance variables. A bit of pincushion distortion will almost certainly need to be induced as well, else barrel distortion propagated by the distance variables make image edges bulge.

 

So yes, it should be possible to get everything sharp as a tack and neutral density filtering of brightness will almost certainly be needed. Getting a sharp image is one thing, to have it hit the surface of the CRT rear  projection screen as a rectangle will be the fun part.

 

Edited by Trash80toHP_Mini

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Short version: from my perspective, a vacuum formed or drooped thin plexi cover would be your optimal solution.

 

TLDR

 

Forgot to mention cooling noise. IIRC the projector sounds a bit like a tiny jet engine. Hopefully newer ones are cooler running and a lot more quiet. Think Classic/MDD. No problem for ceiling game projection or rear facing screen movie projection, but could be annoying for desktop mode. Something to think about.

 

Better solution all around would be vacuum forming clear plexi replacement CRT faces. I've done a first round and results were better than expected with a rudimentary setup and heating scrap plex I had on hand in the oven. Switching to very thin plex and a better setup should yield useful LCD covers. No refractive index to speak of for acrylic, but I wonder if convex-convex lens configuration and CRT face glass refraction might induce slight, uneven magnification of the LCD image.

 

After disassembling a display for recycling, I'm wondering if you could vacuum form an LED backlit LCD. [}:)]

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Quick update: As you can see from the broken shard of glass below, the CRT cutting was unsuccessful!

 

136898258_IMG_20190524_1818542.thumb.jpg.23d8ad4119f600ff05400af80234e8d3.jpg

 

But perhaps it was a blessing in disguise, because as you can see the glass is very dark, thick and has a stipple texture on the inside. It would have led to poor clarity from the LCD.

 

But it gave me an idea - using my remaining CRT I made a silicone mould of the convex surface and then made a cast using clear polyurethane resin:

 

127888300_IMG_20190524_1818342-3024x2268.thumb.jpg.ae7485deafaff30b1f3945cdd3cb6a61.jpg

 

Truth be told, it was an immense amount of work to achieve this result. I had multiple failed attempts and even made my own pressure chamber so that the resin would be free from air bubbles!

 

Stay tuned for final assembly!

Edited by ants

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Not sure how I missed this thread, but this is incredible! 

 

I’m excited to see the finished product!

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You pulling this off would be incredible. Please document how you do it. I need this for my arcade monitor someday!

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Hmm.  I wonder if it'd be cheap enough to just have a mold made and get new glass.  It's not a complex shape, relatively small and it'd be useable on every compact model except for the LC 5xx line.  Preliminary Googling shows that it's not too expensive.  MUCH cheaper than injection molding.

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