A1200 display has a green tinge - what's wrong?

[gizmomelb]

Hi all,

my Amiga A1200 (PAL) has recently gotten 'ill' as it now displays a slightly green tinged screen instead of the default workbench 3.x grey.

'green' screen pic 1

'green' screen pic 2

this is the colour it SHOULD be!


I've tried hooking the A1200 to a friend's 1084S, the TV and another friend's 1960 monitor - the same green colour is displayed on all of them so I'm assuming it's definately a video related hardware fault.

Any help or comments as to what the problem might be, or where/what I should be probing with my multimeter would be most appreciated.

Thanks,
Gizmomelb

[gizmomelb]

hi all,

thanks for the comments and help.

some extra info:

I tried at least three different RGB cables (SCART, 9 pin 'D' and 15 pin 'D') but I haven't tried the RF yet.

the 'colour it should be' is my mate's A1200, my machine was working fine before the green appeared (and I checked the WB colour prefs... unfortunately this isn't a practical joke  ).

I'll try the RF tonight, and have a probe around and test the caps and resistors on the RGB this weekend and report back if I have any luck.

Thanks heaps!

[gizmomelb]

hi guys,

no, no speakers next to the monitor(s).  I tried 2 different models of 1084S, a 1960 and my TV with SCART input.  All of them have the green colour.

[gizmomelb]

Hi,

I've removed the Blizzard 1230 from the Amiga, so it's just got the HDD in there.  I've also tried it with 4 different A500 power supplies, so I don't think it's a power issue.

The SCART is an RGB 23 pin cable.  I tried the composite and it also has the yellow video output.  I haven't been able to find an RF cable yet to try.

Hmm, someone at the local user group might be able to resolder the DAC, I personally don't feel confident enough to do it.

Regards,
Gizmomelb

[gizmomelb]

Hi,

to sum up for everyone - I've tried an RGB-> SCART cable, RGB->DB9 analogue cable and an RGB->VGA (DB15) cable.  I've tried three different monitors as well as composite video output and 4 different power supplies.  The video output to all display devices is yellow (but the mouse pointer is red) if I use workbench, auto-boot games or demo disks (ie: it's not a WB setting).

So I guess if it's a faulty resistor, I should go looking for A1200 schematics so I can figure out which ones to look at with my multimeter, as well as what values they should be.

Thanks!