English Amiga Board

Go Back   English Amiga Board > Support > support.Hardware

Thread Tools
Old 07 September 2008, 18:48   #1
Magno Boots
Zone Friend
Join Date: Feb 2006
Location: Hertfordshire
Posts: 688
A1200 not displaying correct colours


One of my 1200's has developed a problem with the colour display. This isn't a gradual problem. It has happened overnight.

I'm not sure which colour is affected but black now appears green/brown and white also has a green tinge (see pics).

Attachment 17850

Attachment 17851

I have tried different RF cables and output via scart with no difference.

CFHD, idefix adaptor and accellerator have been disconnected - no change.

The machine has an internal CD fitted and I cannot see that the RF shield is pressing on something it shouldn't.

I'm loathe to remove the CD because it's glued in! . I think I may have to. (more )

Possibly a knackered chip?, all advice welcome.


Last edited by Magno Boots; 18 September 2008 at 00:04.
Magno Boots is offline  
Old 07 September 2008, 19:27   #2
Posts: n/a
I know it sounds daft, but have you checked to see if its the tele is faulty and not the Amiga.

You want to try every combination of video sourced from the Amiga to alternate outputs.

the a520 adapter via RF to Lounge TV, Bedroom TV, Kitchen TV, etc
the a520 adapter via Composite to Lounge TV composite / phono scart, etc
a1200's composite video to Lounge TV composite, photo scart, etc
a1200's RGB 23 way D to RGB monitor, RGB Scart (TV)

and so forth. If they're all knackered then its gonna be a chip.

If you've got kids, question there move abouts around about the time the fault developed, look for the obvious signs of lying.

Sounds like an annoying problem.
Old 07 September 2008, 23:20   #3
Magno Boots
Zone Friend
Join Date: Feb 2006
Location: Hertfordshire
Posts: 688
Thanks for the advice Skipster.

I have tried different combinations of TVs and Amigas and the problem lies somewhere within the motherboard.

It has been completely stripped and a few dodgy looking solder points underneath have been 'touched up' so to speak. No joy.

The Alice chip is getting pretty warm, but I think this is normal.

I'm going to bin it and use the board from the miggy I found at the tip.

Thanks again.
Magno Boots is offline  
Old 08 September 2008, 02:39   #4
I hate potatos and shirts
rkauer's Avatar
Join Date: Oct 2007
Location: Sao Leopoldo / Brazil
Age: 54
Posts: 3,482
Send a message via MSN to rkauer Send a message via Yahoo to rkauer
Bad CXA1145 (video encoder) or busted/cold joint in one of the R-G-B SMD resistors right behind video encoder "entrance".

The CXA1145 can be replaced for a much more modern CXA1645 (fully pin-compatible).
rkauer is offline  
Old 08 September 2008, 03:00   #5
hastala vista winny vista
coze's Avatar
Join Date: Feb 2006
Location: mt fuji
Age: 42
Posts: 1,335
Send a message via ICQ to coze Send a message via Yahoo to coze
please don't bin it, it sounds fixable, and I'm sure there are people on this board who would like a chance to give a new life to it. (read : me)
coze is offline  
Old 09 September 2008, 06:49   #6
Registered User
Hewitson's Avatar
Join Date: Feb 2007
Location: Melbourne, Australia
Age: 38
Posts: 3,747
Its likely to be the SMD resistors rkauer mentioned, I recently had a similar problem on a megadrive and they were the cause of it.

Measure them with a multimeter, you won't get an accurate reading because theyre in circuit but at least you can see if any are open circuit or reading ridiculously high.
Hewitson is offline  
Old 09 September 2008, 14:40   #7
Registered User
twizzle's Avatar
Join Date: Sep 2005
Location: taunton.som.uk
Age: 70
Posts: 681
@Magno Boots

dont bin it, mathew at amigakit can do MB repair`s
twizzle is offline  

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools

Similar Threads
Thread Thread Starter Forum Replies Last Post
Displaying images Tiddlypeeps Coders. Tutorials 40 30 August 2012 11:11
A1200 Dying? Odd Colours Badders support.Hardware 29 23 November 2011 21:29
displaying correct MagicWB-colors Bamiga2002 support.Apps 3 26 July 2010 12:06
A1200 RGB colours are "different" PowerPie5000 support.Hardware 21 10 January 2009 23:30
More colours than 256 possible in A1200??? ORSM T New to Emulation or Amiga scene 8 15 May 2007 23:55

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

All times are GMT +2. The time now is 18:17.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, vBulletin Solutions Inc.
Page generated in 0.12191 seconds with 13 queries