Riddle me this: iMac DV

[MD Willington]

Picked up an iMac DV 400 (graphite with DVD) for $10 USD, works fine with the external monitor, but that takes up too much room.

Most of the stuff I've read online if FUD or WAG's, some elude to the "analog board", shorted flyback transformer... pram battery...

Well anyway whatever it is the display is totally hosed, the screen comes up the wrong color, its mushed and the picture looks like a smudged pastel work of art..

Any of you guys ever fix one of these... It's a neat little system and I'd like to get it working...

Thanks guys/gals!

MD

[kc8adu]

Re: Riddle me this: iMac DV

a picture is worth a thousand words.
just fixed 2 monitor related issus on imacs.1 was solder joints on the crt socket board.
other was a weak crt.

[MD Willington]

Re: Riddle me this: iMac DV

I'll try to get a picture of it ASAP.. one thing I did spy is a large KMM cap on the analog board, it has a vinyl disc on the top that is slightly bulged, but I've seen the plastic tops on large caps like that before with the cap's can flat underneath... but maybe it's a possibility. Those things get kind of warm inside.

[kc8adu]

Re: Riddle me this: iMac DV

gently push on the top.
if its just the plastic puckered a bit it will push down easily.if its hard the cap is bulging.
bet you have a dead crt.not that big of a deal if you can do minor circut mods so you can set bias/drive when you are done.

[MD Willington]

Re: Riddle me this: iMac DV

I read a post where an Apple Tech (not sure what thats worth all they do is swap parts) was trying to get the machine to work with the internal monitor unplugged and an external monitor plugged into the vga port. The device would absolutely not post unless the defective CRT was still attached to the system... not exactly sure what he did though to try it.

[MD Willington]

Re: Riddle me this: iMac DV

Sorry for not getting a picture of the monitor, quite busy at the moment.

[MD Willington]

Re: Riddle me this: iMac DV

Okay no picture but this happens:

Brightness and contrast at factory cause huge saturation, I have to peg them back to a dar sort of greenscale image.

Pincussion is hosed, I can get the left side straight but the left side is still convex outward, same thing happens going the other way.

[arneson]

Re: Riddle me this: iMac DV

Horizontal damper diode can do this. It may be descrete right under the output or it may be built in.
A lot of times If the high voltage section gets whacked, it is recomended to replace many of the components in the area that could have been stressed.

[kc8adu]

Re: Riddle me this: iMac DV

i doubt the damper is causing the geometry issue.
it could still be in the h-out stage though.
if you get a big smearout when turning up contrast try checking/adjusting g2/screen.
i still vote for a junk crt and maybe corrupted eeprom.

[MD Willington]

Re: Riddle me this: iMac DV

Well, I think I just need to find a nice used LCD and not worry about the CRT...

[arneson]

Re: Riddle me this: iMac DV

$10, can't cry about that.

[MD Willington]

Re: Riddle me this: iMac DV

Nope.. it has both OS9 and OSx on it too!