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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

Best reply

louie

Level 4

2,950 points

Posted on Mar 28, 2006 8:27 AM

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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30 replies

Craigwd_2000 Author

Level 4

1,309 points

May 25, 2006 11:44 AM in response to Appaloosa mac man

No. Actually what I really need is a replacement circuit board for my Macintosh Color Display. That or someone who can replace the capacitors on my circuit board for really cheap. Where can I find replacement parts? Maybe eBay? I'm starting to think I may also need a replacement LC II Revision B Logic Board for my Performa 405. That's the Mac I'm using the Macintosh Color Display with. Also the Mac has been having sound issues (static noise caused by Logic Board or CPU fan) with my old Sierra On-Line adventure games still too.

May 25, 2006 12:47 PM in response to Craigwd_2000

Most service people are not pulling those apart to harvest the parts, but are selling the whole thing if they decide not to trash them.

Preowned.com does not even have the boards for it any more.

Craigwd_2000 Author

Level 4

1,309 points

May 25, 2006 1:51 PM in response to Grant Bennet-Alder

If it's impossible to get parts then what should I do? I found a guy online that replaces PC motherboard capacitors. I wonder if he could replace any suspect capacitors for me. I think I'll send him an email to ask about it. If he does end up repairing it I may post an update eventually.

May 25, 2006 6:17 PM in response to Craigwd_2000

For the amount of money it will cost to disassemble, ship, fix, ship, reassemble -- you could have a working used one with a modest warranty that is much better.

This would be a good project for YOU to learn to solder on. You can't possibly make it any worse, its broke!

Craigwd_2000 Author

Level 4

1,309 points

May 25, 2006 6:35 PM in response to Grant Bennet-Alder

I would except I don't have a solder sucker. Do you know how expensive those things are? You need one when working with multi-layered PCBs. I'm not even sure if the board in question is single or triple layered too.

May 25, 2006 7:06 PM in response to Craigwd_2000

US$3.29 bulb, $7.79 spring loaded at Radio Shack:

Radio Shack online search for desoldering

You cut the legs off the dead component, then de-solder the legs. That makes it easy to clear the hole without damage.

Craigwd_2000 Author

Level 4

1,309 points

May 27, 2006 2:59 PM in response to Grant Bennet-Alder

What if the PCB I'm desoldering on turns black? Does that mean my OEM Adaptec SCSI card I'm trying to repair is now dead? It was made in 1996 & it had Nichicon capacitors installed on it which according to the Wikipedia article are bad. Here's a link to the article I'm referrring to: http://en.wikipedia.org/wiki/Bad_capacitors.

May 27, 2006 5:33 PM in response to Craigwd_2000

Is that black from capacitor ooze or black because the fiberglass-epoxy board got hot from the soldering iron or the silver traces and holes became blackened?

My soldering technique leaves a lot to be desired, but I know that to solder stuff, the metal must be shiny, and the flux is supposed to keep it shiny while you heat it up.

Craigwd_2000 Author

Level 4

1,309 points

May 27, 2006 6:01 PM in response to Grant Bennet-Alder

The silver traces & holes on the epoxy board have become unusable. Or at least it appears that way. This OEM Adaptec AHA-1535A ISA SCSI (it may be EISA but it's hard to tell)card was given to me by an IT person who thought it was a throwaway card. It appears to have a BIOS. It might be disabled. If possible I'd like to repair the damage & maybe hack it so the BIOS can be re-enabled. Radio Shack didn't have the necessary capacitors I needed for my monitor either. It looks like I may have to look online. My dad knows of some good possible suppliers too. If the card or Monitor can't be repaired I'd like to at least keep the monitor in case I find a suitable motherboard. The SCSI card was intended to be a add-on for a 486 intended for Sierra games in DOS (it's based on a 3 PCI/4 EISA slot OEM Zeos Python motherboard). Some will be run on Windows 95 OEM SR 2 for compatibility reasons. If worst comes to worst I intend to replace the SCSI card with a Adaptec AHA-1542CF/CP. If I'm lucky enough to win a EISA AHA-16/17XX card through eBay though all the better.

Craigwd_2000 Author

Level 4

1,309 points

May 28, 2006 8:14 PM in response to Craigwd_2000

Update: I bought a desoldering braid & desoldering bulb from Radio Shack. The desoldering braid appears to work. The desoldering bulb on the other hand appears to be of questionable quality. I got the solder molten but when I tried to suck it up it didn't work. I even took the tip of the bulb out but there wasn't any solder inside it. What am I doing wrong here? I really don't want my monitor or motherboard I hope to save the end up the same way.

louie

Level 4

2,950 points

May 30, 2006 10:40 AM in response to Craigwd_2000

This is a great learning experience for you! It's not going to be cost effective, however. Finding bad capacitors is difficult. Just guessing doesn't cut it, so often people will just replace a bunch of them in hopes of solving a problem. Often, it doesn't, but places will sell whole kits of replacement capacitors for some products. One of the best ways of testing electrolytic caps is with an ESR (effective/equivalent series resistance) tester, which start at about $100.

http://www.anatekcorp.com/testequipment/capwizrd.htm

Electrolytic caps often fail from heat and age anyway, but your chances of fixing random failures by randomly replacing a few capacitors is, IMO, low.

BTW, the solder bulbs aren't so hot, but the spring loaded sucker is much better. Technique counts, as you are discovering. Using braid tends to heat the area up too much, causing damage. If you do this all the time, you need an electric vacuum desoldering tool, $500-1000.

AFAIK, the Apple display board is single layer. I hope you read the CRT warning FAQ at repairfaq.

Craigwd_2000 Author

Level 4

1,309 points

May 31, 2006 9:39 AM in response to louie

I'm not so sure about the capacitors they tried to sell me either. The original Nichicons were 22 uF 2.5 Volt capacitors. The ones I ended up buying were Xicon 22 uF 3.5 Volt capacitors. The SCSI card has been acting very temperamental lately. It once even failed a routine Adaptec DOS driver diagnostic check. The IO address was set to 130h via the dip switches at the time. Did I buy the wrong capacitors? They seem to be of a different size & shape than the originals. All of this is really starting to make me wonder if Radio Shack sold me high quality parts or not. I'm also still not sure if I'll be able to find the right capacitor for the monitor. I think finding one rated at 2200 uF might be tricky. Not to mention the fact that that's an insanely high uF rating.

May 31, 2006 1:16 PM in response to Craigwd_2000

Higher voltage or a bigger can is generally not a problem. Somewhat more capacitance is usually not a problem, but some circuits are tuned to a particular value (generally that is a bad design idea, because they become less effective with age). You do not want to cut corners on the temperature range.

Craigwd_2000 Author

Level 4

1,309 points

May 31, 2006 6:41 PM in response to Grant Bennet-Alder

I have a new problem. Some of the solder I was using accidentally got onto the ISA card's gold contacts. It instantly turned black. I tried to desolder the mess. It doesn't appear to be working. My soldering iron is a 23 Watt Weller. I made sure to get a finer bit to be on the safe side. Now I have an even bigger problem. Originally one of the main AIC chips was covered up by a sticker. I took it off for obvious reasons. The chip turned out to be an AIC-3370P. I looked through all the driver documentation. There's no mention whatsoever of this chip being supported in DOS. In which case it may be pointless to continue. No Windows 95 driver exists for it either. Or if it does it's part of a driver bundle (one file that may possibly be written for both chips). I really am truly stumped this time.

There were a couple of other interesting drivers. Unfortunately the documentation appears to be inadequate. Adaptec's site lists the AHA-1540X series as the SCSI cards that typically use the AIC-3370. The only drivers I could find were outdated Windows 3.11 drivers. I'm also still not really sure how to fix the monitor either. The dissassembly procedure alone looks very hard.

louie

Level 4

2,950 points

May 31, 2006 6:44 PM in response to Craigwd_2000

Although there are dozens of parameters that describe capacitors besides just the capacitance and voltage, for most all electrolytic applications, a higher voltage is OK if the capacitance is the same. Capacitance tolerance is typically +/- 20% anyway.

2200uF isn't high value at all. Car stereo folks put farad value caps in their systems. What's harder to find is the high voltage ratings used in most display circuits.

Macintosh Color Display