Macintosh Color Display

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Craigwd_2000 Author

Level 4

1,309 points

Macintosh Color Display

I just bought a used Macintosh Color Display from a local thrift store. I have brought it home only to find that the adjustment holes on the back seem to have no effect when a tool is inserted & I attempt to adjust the screen's geometry. For my tools I'm using a $15 Kronus toolkit I bought from our local Radio Shack store. The monitor is currently hooked up to a Mac Performa 405 with Mac OS 7.5.5 & maxed out RAM & VRAM. Through trial & error I eventually figured out that I needed to enable the LC Monitors extension for the Macintosh Color Display to show up as a valid choice in ColorSync's list dialog box that opens when selecting the monitor model. I have also downloaded a manual for it from Apple's Support website too. According to the manual I'll need to take apart the monitor to get at the geometry adjustment controls. I also need to find the Apple Display Utility download in the event I should need to attempt to calibrate it. Is the only feasible way to adjust the monitor's geometry by opening it up?

refurbished 17 iMac G5 1.8 GHz & refurbished 12 PowerBook G4 1.5 GHz, Mac OS X (10.4.5), 512 & 768 MBs of RAM

Posted on Mar 27, 2006 11:49 AM

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Answer 1

Best reply

louie

Level 4

2,950 points

Mar 28, 2006 8:27 AM in response to Craigwd_2000

From memory and peeking at my closeted Macintosh Color Display, only 3 adjustments are available from the rear without removing the cover. They require a hex adjustment tool. The other adjustments are only accessible by removing the cover, and they are in the rear center. You do not really need the adjustment software. You can display a known graphic, such as an even grid, and do the adjustments.

I can't recommend anybody taking the cover off and operating the display in an attempt to calibrate it unless they are familiar with the dangers and safety precautions needed to work around lethal high voltages.

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Answer 2

Mar 28, 2006 10:23 AM in response to Craigwd_2000

You do have the pdf for repair from whoopis?
I have a Service-CD bought from Canada with a Display Adjustment Utility 2.0(OS 8.1 iMac/G3) and Display Service Utility 4.2.1(Os 7 up)from 1998.Don't know wether you can use them.

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Answer 3

Craigwd_2000 Author

Level 4

1,309 points

Mar 28, 2006 11:48 AM in response to AppleIIFreak

I have a Service CD I bought off eBay dated 1984-2004. Should that have the Apple Display Service Utility on it? If so will the file fit onto a floppy? I was thinking of transferring the file to a floppy via my PowerBook G4 or iMac G5.

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Answer 4

Mar 28, 2006 11:50 AM in response to Craigwd_2000

First file 34 kb,second file about 300kb

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Answer 5

Craigwd_2000 Author

Level 4

1,309 points

Mar 29, 2006 2:07 PM in response to Craigwd_2000

Update: I have taken the case off of my Macintosh Color Display. I guess I shouldn't have been so quick to mark this topic as Solved & will let it continue a little longer. I also looked through Apple's Service Manual for the Macintosh Color Display & discovered it has a fuse on the circuit board below the neck of the picture tube on the left side. My fuse looks grayish white in the middle. For some odd reason the controls that move the picture on the monitor up & down & left to right sideways don't seem to work. Does this mean I need to replace the fuse? Or do I need to run the Apple Display Service Utility before these functions will be operational? This is also the reason I posted in the topic CRT Discharge Tool Needed. According to Apple's Service Manual for the Macintosh Color Display if the fuse has actually blown I'll need to discharge the CRT first before I can replace it.

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Answer 6

Mar 29, 2006 2:32 PM in response to Craigwd_2000

I personally would look for a TV-Repair-Shop to get that Tool-and advice! Some say you can damage electronics by discharging to fast(needs a 10 MOhm resistor).
You shouldn't come near the "flyback" trafo -but you make take out and exchange the fuse with an isolated pincers(?) and rubber gloves.

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Answer 7

Craigwd_2000 Author

Level 4

1,309 points

Mar 29, 2006 2:59 PM in response to AppleIIFreak

I was thinking of using tweezers to remove the fuse safely. I'm not sure if my dad has rubber gloves or not though. How thick do the gloves need to be? Would using tweezers be a safe way to remove the fuse?

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Answer 8

louie

Level 4

2,950 points

Mar 29, 2006 7:09 PM in response to Craigwd_2000

The fuse almost certainly protects the whole power supply, not just the geometry circuits. Assuming you are using the proper hex adjustment tool, if the adjustments do nothing, their circuitry is probably broken and that's why it was so cheap.

Apple most likely believes it is beyond the scope of this forum to instruct in how to do high voltage repairs safely. You'll have to study the references or get experienced advice.

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Answer 9

Craigwd_2000 Author

Level 4

1,309 points

Mar 30, 2006 12:11 PM in response to louie

I found a PDF from Apple online which details how to discharge the CRT. It even tells you how to make your own CRT discharge tool. Here is the URL: http://www.ct-scan.com/iMacATX/displaydischarge.pdf.

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Answer 10

Mar 30, 2006 5:18 PM in response to Craigwd_2000

The CRT bottle, the Big Red Wire, and the Flyback transformer can store a charge of over 10,000 Volts for months after the power is removed. If you were to connect that through your body, e.g., hand-to-hand, it could stop your heart.

I am told the US Navy trains you to keep one hand in your back pocket when you work on this or possible live high voltage equipment.

The CRT bottle has a high vacuum, and if you were to break it, it could implode and send shards of glass in all directions, including your eyes. (Wear "chemistry goggles").

A large mirror is helpful so that you can watch the display while you make adjustments, without having to reach around it while it is "hot".

I also suggest you not work alone.

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Answer 11

Jon Smith

Level 4

1,390 points

Mar 30, 2006 6:06 PM in response to Grant Bennet-Alder

Hello all,

Had a friend who was working on a TV when it imploded. Made a tremendous WHOMP as the vacuum tube inhaled everything around it, gave off a little puff of sort of toxic looking white smoke, and scared the living s..t out of him.

Regards ..... Jon

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Answer 12

Craigwd_2000 Author

Level 4

1,309 points

May 21, 2006 7:12 PM in response to Craigwd_2000

Update: I have taken off the case of the monitor yet again to perform the adjustments. The problem is simple. I had adjusted it previously but the setting won't stick & now the left & right edges of the image look distorted. The odd thing is they looked fine at the time when I did the adjusting. I also had the fuse tested at Radio Shack & they said it was still good. I have also discovered something quite disturbing while the monitor was open. There is a capacitor inside with a y shaped marking on top of it rated at 2200uF. I also recently read a Wikipedia article which suggests that such capacitors with a y shaped marking on top & rated over 480uF may need to be replaced. It wouldn't surprise me in the least considering the monitor was made in November 1993 according to the sticker on the bottom edge at the back of it. I also had a recent experience with Apple's Tech Support over the phone via their 1-800-SOS-APPL number. I told them I suspected bad capacitor/s may be the cause of my issue too. I was also sent a survey by email shortly afterward. When I called their Tech Support they said the monitor was purchased from Apple in 2003 but I bought in sometime during the first quarter of 2006 from the local MVAC Thrift and More store. Will the repair be covered as a manufacturer's defect too despite the age of the monitor? Should I take the monitor to my local Apple Authorized Service Provider? More importantly will I have to pay for the repair?

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Answer 13

louie

Level 4

2,950 points

May 21, 2006 9:51 PM in response to Craigwd_2000

I don't speak for Apple, but in my opinion, they have no obligation to repair a 13 year old display. You'll have to ask them yourself.

In addition, electrolytic capacitors all age and can go bad. Repair technicians always suspect aging electrolytic capacitors in electronics that are this old and have odd problems, such as adjustments that change.

What the Wikipedia article probably referred to was a situation about 5 years ago where capacitors were counterfeited with a stolen formula for capacitor electrolyte which was not correct. Apparently millions of these units made their way into legitimate electronic goods, and failed quickly. I doubt that the case markings or value alone can determine if the unit is counterfeit or not, but the age alone of any electrolytic capacitor makes it a suspect.

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Answer 14

May 21, 2006 10:04 PM in response to louie

Some of those bogus capacitors, brown with "Lelon" brand, made it into the original Airport Base Station. Apple did not fix them for very long. There are lots more horror stories about them appearing on PC motherboards.

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Answer 15

May 22, 2006 12:12 AM in response to Craigwd_2000

Craig,

The last 8 17" monitors we purchased were $1.00 a piece for a kid's LAN. Fixing monitors now is totally academic.

Years ago I asked an authorized Apple Service Center about a monitor repair. They said they were only trained on one model. All others were shipped by UPS to knowledgeable technicians.

That meant I was equally non-trained to repair the monitor. Scary thought. If a monitor has a fuse that is soldered to the motherboard, Radio Shack sells fuse holders with tabs for mounting to a printed circuit board. Buy two, bend the tabs together so that the two are bottom to bottom. Then the assembly will push down on top of the dead fuse. Install the fresh fuse into the top fuse holder and no soldering is required.

Shipping is cheaper than local training, Swapping out is cheaper yet.

Jim

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