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The Compact Mac CRT Guide

Scott Baret

Well-known member
It seems to me that the pattern of holes showed up on analog boards sometime in late 1991 or early 1992 around the time the Classic II came out.

Apple may have been using up older stock of case backings, sort of like how they made SEs in 1991 to presumably use up parts. The sound vents are found on mid-1992 and later Classics. My guess is that they started putting these in because of complaints that Classics aren't loud enough--put both a Classic and an SE on speaker volume "7" and you'll see what I mean.

The new question--was the concept of speaker holes thought of long before it was implemented? Could it be Apple got complaints after the first round of Classic IIs that the stereo sound should sound better from the internal speaker?

 

Aoresteen

Well-known member
I recall around 1987 or so a company that was offering AMBER replacement screens for the 128, 512, and Mac Plus. I always wanted one. Seemed neat!

Anyone know which company it was and whose tube they were using? And is it available today?

Thanks!

 

mfortuna

Member
Thanks to a posting on vintage computing, I found this excellent forum. One of my vintage machines is a MAC Classic. Because of jittery video, I recently replaced the version A analog card with a version B. I also had to use the yoke assembly that has the correct connector for the rev B analog card.

The video looks great now and doesn't jitter.

Mike

 

Bunsen

Admin-Witchfinder-General
AMBER replacement screens/ available today?
$19 green or amber 9inch monitors from Timeline Inc.

Note that these are NOT drop in replacements for the CRT in a compact Mac. It MAY be possible to swap the CRT and use the Mac's existing analogue board and yoke, or it may not. Using the Timeline monitor's a/b and yoke would probably require extensive mods. Research left as an exercise for the reader.

 

Interceptor2

Active member
Just a tech question regarding the CRT, I notice my small collection of Mac Plus' don't have dag wires - usually a sin. 8-o I've seen piks of US models with dag wire. :?: Is this intentional?

 

JDW

Well-known member
Since this sticky thread is the "be all guide to CRTs," I would like to ask a very common and related question regarding defective or potentially defective CRTs. People who come to this thread are most likely looking for more than just historical tidbits on vintage Mac CRTs. Indeed many coming here are most likely looking for detailed information on how to test a potentially defective CRT and then how to replace it with something suitable. I therefore would like to pose this question...

If a vintage Mac owner has been fiddling around inside their Mac, then bumped something which caused their CRT to flake out (e.g., displaying little more than a white glow at all times), is it safe to remove that CRT and test it in a known good Mac of the same type? And what about CRTs that experienced a heater to cathode short? Would placing potentially defective CRTs and a known good Mac put that known good Mac (analog board and/or digital board) at risk of being damaged by that that CRT?

If the known good Mac is at risk of potentially being damaged by bad CRT during testing, then how does one appropriately test a potentially bad vintage Mac CRT?

Thank you.

 

Scott Baret

Well-known member
BREAKING NEWS.

There is a third brand of CRT used in these old Macs.

Found inside a late 1987 manufacture American Macintosh SE: a Toshiba CRT.

It has a large amount of red paint around the anode cap.

This is the first instance of this type of CRT I've ever seen, and I've taken apart approximately 100 compact Macs over the years.

It is unknown if this was a replacement CRT or not. The Mac has an early squirrel cage fan for what it's worth.

The label has part number E2728B4-TCOISDHT and the unit was made in Japan.

 

Franklinstein

Well-known member
Some additional info:

The Clinton CRTs have nothing wrong with them but they have no anti-glare coating, which makes staring at them in a bright area an eye-straining experience. The Samsung units, on the other hand, are anti-glare. 

An upgrade in the '80s saw people swapping their old Clinton CRTs for Samsung or other anti-glare tubes. One other manufacturer was Orion, if someone comes across one of those. This may explain why you would find a non-Clinton tube in an early Mac, in addition to the fact that tubes do sometimes require replacement for a variety of reasons and an original tube may not have been available.

 

CompaqMac

Member
This may explain why you would find a non-Clinton tube in an early Mac, in addition to the fact that tubes do sometimes require replacement for a variety of reasons and an original tube may not have been available.


I’m not sure if this even really still in debate, but if you look at the very first issue of Macworld magazine, they do a tear-down of the original 128k Mac with detailed photographs.  If you look closely, you can clearly see that it has a Samsung CRT.  This is pretty strong evidence that Samsung CRTs existed from the factory  even in some of the earliest Macs.

 
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ironborn65

Well-known member
Hi all,

FYI

I just moved a MB from a Mac Classic (Type A analog board), to a Mac Classic II unit (Type B analog board), it worked just fine.

best

Pierfranco

 

JDW

Well-known member
I just moved a MB from a Mac Classic (Type A analog board), to a Mac Classic II unit (Type B analog board), it worked just fine.


I can only assume that "MB" = "motherboard".

I think that is very interesting. Thank you for sharing. And while I am no fan of overbearing forum moderation by an stretch of the imagination, I feel strangely compelled to point out that this thread is solely focused on CRTs, which are totally different and completely separate from motherboards.  The world isn't coming to an end because you posted here. :)  But your post does feel strangely out of place.  And now my own post is out of place.  Maybe I can remedy that with this...

CRT, CRT, CRT, CRT, CRT

Boy how I love CRTs!

Vacuum Tubes!  Gotta love 'em!

And there you have it.

 
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