Replacing the Mac SE CRT monitor

The CRT monitor on my Mac SE was damaged during a floppy drive install. The only way to fix it was to replace it. Fortunately, I have a non-working Macintosh Classic II that I've kept around for parts, so I decided to use it's CRT as a replacement.

Keep in mind that there is a potential of high voltage discharge while working with these components. Be careful!

Opening up the SE is quite simple. There are four screws that need to be removed using a Torx driver.

Once opened, there are a number of cables that need to be disconnected.

Then the logic board, disc drives and power supply panel need to be removed.

Once all of these components are removed, the CRT is the primary component left.

There is still an attached yoke and anode connector that must be removed.

These areas are potential high voltage discharge areas. ABSOLUTE care must be exercised at your own risk. Removing the yoke requires loosening the clamp screw at the yoke's end. The yoke can then be pulled off.

To remove the anode, the rubber body must be squeezed and then removed by rocking the contacts back and forth until it releases.

Now the CRT can be removed by removing four screws.

Basically the CRT on the Mac SE is identical to the Macintosh Classic II. However, the connectors for the yoke are not. The SE has a larger 4 pin connector.

The Macintosh Classic has a smaller connector. 

In addition, if you were to swap out the connectors, the yoke is not tuned correctly for the SE. The image develops an unfocusable overlap on the image side. So be sure not to damage the SE's yoke.

Once the new CRT replacement is made and all of the removed components have been replaced, the system needs to be turned on so that the image can be adjusted. The first adjustment should be the tilt. It's very unlikely that you have replaced yoke in it's correct orientation.

This adjustment is made by slowly revolving the yoke around the CRT neck until the proper image is obtained.

Next is the vertical and horizontal adjustments. These are made by adjusting the potentiometers on the SE's power supply board.

Next the focus and luminosity can be adjusted by similar potentiometers in the same area.

Everything should work well now. In this case one more adjustment could be made.

The image is not quite centered in the CRT. This can be adjusted by moving the centering rings on the yoke.

Macintosh SE

The Macintosh SE was introduced on March 2, 1987. It has the same iconic form factor as the original Macintosh, but with slightly different styling and color. This model has significant improvements over it's predecessor, the Mac Plus. It's most notable feature being the installed hard drive.

I picked up an inexpensive unit on eBay. They can generally be found for a reasonable price (under $100). However, the SE shouldn't be confused with the SE\30 which was introduced on January 1989. These models will sell for considerably more. Though I owned a SE\30 along time ago, I had considered picking one up for nostalgic reasons, but the collector's demand for them are too high for my taste. 

Here are the specifications for the SE:

Processor: Motorola 68000, 8 MHz

System Bus Speed: 8 MHz

ROM Size: 256 kB

Data Path: 16-bit Level 1

RAM Type: 150 ns 30-pin SIMM

VRAM Type: Built-in

Standard RAM: 1 MB

Maximum RAM: 4 MB

RAM Slots: 4 (in pairs)

Standard Hard Drive: 20 MB

Int. Hard Drive Type: SCSI

Standard Disk: 3.5 in, 800 kB, 800 kB x 2 (auto)

Exp. Slots: SE PDS

Battery Type: 3.6 V lithium

Display: 512x342 9 inches (23 cm) monochrome[2][6]

Video memory: 512x384x1

Supported Mac OS: 3.3–7.5.1, 7.5.3–7.5.5

Avg. Weight: 17.0 lb/7.7 kg

An advertisement in MacWorld Nov 1987 has the SE selling with a 20MB hard drive, keyboard and mouse for 3319 USD. That's $7,036.89 in today's dollars!