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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: gizmomelb on March 16, 2006, 01:47:28 PM
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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 (http://craigwp.customer.netspace.net.au/pics/green1.JPG)
'green' screen pic 2 (http://craigwp.customer.netspace.net.au/pics/green2.JPG)
this is the colour it SHOULD be! (http://craigwp.customer.netspace.net.au/pics/diagnostic.JPG)
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
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If you are lucky it could be just some loose soldering on one/more pins for RGB port.
Other than that I have no idea.
BTW, Have you tried a different cable?
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How come the mouse pointer is red than ?
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Because blue signal is missing? I don't know
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Because blue signal is missing? I don't know
I'd agree. It looks like blue is weak/missing.
When you hooked it to a TV, did you use the RF out or a SCART cable? If you used a SCART, try the RF out and see if that looks right. If it does, you've probably got a loose/bent/broken pin in your 23-pin video port. If it also looks like blue is missing, it might be a dried up capacitor or poor solder joint somewhere in the video output.
Either way, I don't think it's anything TOO major, if the machine is otherwise behaving properly.
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If you try another cable and that is not the problem You may have to open up the back of the monitor and first try turning the Blue guns colour adjustment. Sometimes these can be reached through some service holes in the back of the monitor without taking the back off. (these are located in an easy location to reach usualy on the back of the guns circuit board) Lables "R" "G" "B" if this makes no difference then it may be that the gun itself is bad or a solder joint has let go on the Blue circuit.
Do adjustments with caution as there are very high voltages inside the monitor and remember where the adjustment pot was before you turned it so you can turn it back if need be.
EDIT: Ok I guess I missed that you did try a 1960 and it did the same thing. If this is the case then I would make sure that your pins on the Amiga video out are straight and none are missing or dammaged. check the circiut conection from the MB to the RGB out and maybe resolder them carefuly.
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Heeey, be carefull.
I don't think it is the blue component, coz if you're missing blue your workbench should be YELLOW, and not green!!
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I had similar problems with my A1200 using RGB output, but my problems was on monitor RGB connector, i got blue and pink colors, the connection had unsoldered from 1084S monitor. Maybe you have the same problem on RGB connector of your Amiga 1200. As dawiper said before.
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Umm, was the "colour it should be" picture taken when it was OK, or is there more to this than meets the eye ? Details please :idea:
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check to see if the video settings in workbench is set for a monochrome monitor. that is freakishly similar tho how did the curser get away.
another possibility tho unlikely is someone is playing a prank and changed your workbench colors.
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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!
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what type of monitor do you have not by the way the 1984s??
on the front site by the monitor (next to sound wheel/switch)is an little switch
this one switch to rgb or green mode try it maybe you pushed it somtime...
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Just a thought!
Have you got unshielded speakers next to the monitor as this can cause problems
regards
The_Gooze!
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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.
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Strange. To get colors like that the green component has to be inc. and the blue has to be reduced. They also has to be adjusted equally. Example: 10% more green and 10% less blue.
I just tried adjusting the pictures in a photoprogram.
I think it has to more than a loose pin/cable.
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gizmomelb wrote:
I tried 2 different models of 1084S, a 1960 and my TV with SCART input. All of them have the green colour.
All of those screens use the Amiga's RGB output don't they? Have you tried using the RF or composite output?
--
moto
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I have a similar problem with my old A1200, all the outputs (RF, SCART and COMP.) are yellow!
Now my A1200 is in a box getting dust because I buyed an A1 but I want to know what is wrong in it.
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What do you have inside your Amiga?
Have you tried switching Power Supplies with your mate? A faulty 12v line on your PSU will affect video but not the computer.
Is your SCART cable a TRUE RGB cable or is it a composite SCART cable? (If it connects to the 23-pin connector then it IS RGB).
Try connecting the A1200 to an RGB monitor and to the TV via RF at the same time. You could also try the composite output.
Report back.
I personally think that your video DAC needs to be refluxed. 10 minute job if you're good at soldering.
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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
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Does this only happen in Workbench?? Because then it sounds like you have somehow altered the colour slider in preferences :-P
I wonder this because the early boot menu looks normal?? Or did you use a different a1200 for that?
Is this problem present using both composite out, rgb and rf output?? If so, then it is probably some resistor that is burnt out of one colour, because it seems like one colour is missing, which will give the picture a green tint. If this only happen on rgb output, then it could maybe be a bent pin in the rgb output port??
Edit: I see you have tried most of what i suggested after reading the whole thread... :-P It sounds to me like it is very likely that the problem is a resistor or a burnt out trace on the motherboard since this also happens using composite out. I recall someone having the same problem with an a600, and then it turned out to be a dead resistor.
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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!