eMac with weird display problem

Excellent.

I will try this out this weekend.

I will come back and let you know if this works

Thank you

Actually the eMac is never in fact disconnected from the mains power supply.

So would even a dead PRAM battery cause trouble in this situation?

I have also noted that putting the eMAc to sleep then waking it up again resets the display to proper contrast and brightness

I think I know what the problem might be.

I recently purchased a 500gb External HDD. I installed Mac OS X from my installer discs on it.

I tried starting up from the new HDD and, not only did it work fine, but the odd display problem appears to have gone too. Doing this has solved other problems as well; incorrect colour output from my Epson Stylus 740 printer when used with the eMac (Prints fine with my PM 6500/300) and my Mac Help pages not working.

So I think I will need to re-install Mac OS X on my eMac. I hope there is a way to do this without losing everything on the HDD?

Ok. The problem is still there.

I have replaced the PRAM BATTERY. Checking the old battery it seems still to be at about 3.5-3.6 volts. I can't really tell if it's within .1 volts of 3.6v because the scale on my multimeter is too small. Set to 2.5 volts it's off scale, next setting, 25v, it's too small to measure in .1 volt steps. But the old battery can't be far off because the reading as near to 3.5v as my ageing eyes can see and is rock steady. So my guess is the original PRAM battery is fine.

As you know, I've reinstalled Mac OS X on the eMac as well. This restored my Mac Help pages (another problem not mentioned before). But it hasn't alleviated the display anomaly.

Now, the 'symptoms' again -

After 'logging on', my desktop picture comes up. It looks fine. The contrast and brightness are as I would expect.

I get the 'spinning beachball' as usual. Then the 'Dock' appears at the bottom of the screen. Desktop picture still looks ine at this point.

Spinning beachball again for 3 maybe 4 seconds. Then, Bang, the desktop picture turns dark and looks burned out. Immediately following this the menu bar at the top of the screen fills out from right to left.

My next move is to go into 'System Preferences'/'Displays', select 'Detect Displays', and my Desktop Picture is reset to what it should be (i.e. detail in the OS X menu bars).

I still suspect a software problem so, I try looking at the 'system prefs' again. I notice the following in the 'Displays' Prefs - "Number of recent modes - 0, 3, 5, 10"

I can't find any infomation about this setting anywhere, so I experiment with each setting. I found it initially set to 10. After going through 5 and 3, it is now set to 0. Doing all this, restarting each time, made no difference to the problem that I can detect.

I then experimented with the 'colors' prefs. I used the screen calibration walkthrough and have saved 4 different eMac calibrations. All work ok, but I still need to use the 'Detect Displays' button each time I restart the eMac.

I'm stumped!!

I have considered looking at Colorsync profiles and such, but I can't find these on my eMac for some obscure reason.

Oh, by the way, booting Mac OS X installed on my new Western Digital 500gb Mybook HDD, the problem doesn't occur at all.

I forgot to mention the following:-

1) Since my post a week or so ago (2 December 2006), I have been experiencing the odd 'kernal panic' (Multilanguage Notice to restart my eMac)* and,

2) following a three hour long power cut, the eMac, when it rebooted, told me that the date was set to before 2001 and might cause problems.

This I took to be confirmation that your suggestion about the PRAM battery was correct, so I replaced it.

* Disk Utility checked the eMac's HDD to be fine

Ok. Tried starting in Safe Mode as suggested. Display still displayed this odd symptom.

On my Menu bar there is the following -
1) WD Backup Monitor;
2) an icon that looks like a black pair of binoculars over a grey man-shaped pictogram and has options such a 'no administrator' and 'Open Remote Desktop Preferences' (the latter the only one not greyed out);
3) The next icon looks a bit like a coffee mug with vertical stripes, has options such as something called VPN. The only active option is 'Open Internet Connection';
4) Displays,
5) a telephone connection icon;
6) Classic; and
7) Language.

'Displays' looks like a short cut to my Displays Prefs. It has all the monitor settings and the word 'eMac' greyed out at the top of the list. I wonder if this is significant?



PM6500/300 (603e) Mac OS 9.1.x

I've got the eMac connected at home to my PM 6500/300 via a Netgear 614v2 ethernet router. I turned off those setting that you mention until all boxes were empty. I had to turn something about iTunes back on again when I connected my iPod though.

I've also turned off Internet Sharing in the Internet section of the Prefs. It was set to Airport. I have an Airport card installed but it isn't being used at the moment as this eMac is on loan from my parents. In Network prefs something called VPN (L2TP) is configured but not connected.

I can't find the Preference pane called 'Other' that you refer to so I haven't been able to remove the WD Backup menu icon. This came with my MyBook external HDD. I will need to contact Western Digital about this I think.

I still get this strange video switch. Even in Safe Mode it occurs immediately after the clock appears, then the little flag icon (lanquages) appears in the menu bar but before the Modem icon loads (itself then followed by the Displays Prefs icon and three others, the last of which, is my WD Backup icon). So it can't be WD Backup because when the display gets switched WD Backup has still to boot up.

It does appear to be software related however, therefore any advice as to the best method for tracking the offender down would be much appreciated please. It's not like turning off 'extentions' like in OS 9, is it?

By the way, I'm considering turning those Network settings back on. Firstly my home network no longer works and secondly, my mum's brand new iMac which arrived two weeks ago tomorrow, arrived with them all switched on - I took a peek. She doesn't seem to have been adversely affected by this yet.

Hi

"What items are shown in your /Library/StartupItems folder?"

WDBMService folder inside which is "StartupParameters.plist, WDBMService and WDButtonManager.

In 'System Preferences' I can only find four categories - 'Personal', 'Hardware', 'Internet & Network' and 'System'.