Welcome, Guest. Please login or register.

Author Topic: 1200 composite video interference fix?  (Read 2298 times)

Description:

0 Members and 1 Guest are viewing this topic.

Offline tone007Topic starter

1200 composite video interference fix?
« on: June 16, 2008, 09:32:57 PM »
Hi,

I've got an A1200 that works perfectly except for some strange interference on my Commodore 2002 monitor (which works fine with everything else) when using composite output.  No problems (at least not noticeable) on my 17" LCD.  I guess I'd describe it as "swirly lines" going through the screen during drive access and/or higher processor usage.  Not enough to make it unusable, but it's pretty annoying.

I've searched Google and seen references to a problem that sounds similar and that it can be fixed by adding or swapping a resistor, but I've searched and can't find any more details.

Does this sound familiar to anyone?

Thanks.
3 Commodore file cabinets, 2 Commodore USB turntables, 1 AmigaWorld beer mug
Alienware M14x i7 laptop running AmigaForever
 

Offline davideo

Re: 1200 composite video interference fix?
« Reply #1 on: June 16, 2008, 11:03:43 PM »
Hi,

I have the same problem with my towered 1200.

It'll be interesting to see if there is a cure and if it works.

Keep us posted please.

Dave G  8-)
 

Offline wolfchild

  • Jr. Member
  • **
  • Join Date: Oct 2007
  • Posts: 74
    • Show only replies by wolfchild
    • http://www.binarycombinations.com
Re: 1200 composite video interference fix?
« Reply #2 on: June 16, 2008, 11:31:53 PM »
I remember having the same problem years ago on my early revision A1200.

It was only after several years that I found out a fix.  I did something like this:
http://mysite.verizon.net/jartz/amiga/flicker_fix.html

Cheers!
Edwin
-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
self-built minimig 1.1 :: 10ns SRAM :: 3.5MB RAM::ARM board::2GB SD card
VGA -> SCART cables currently available - PM me to order.
 

Offline tone007Topic starter

Re: 1200 composite video interference fix?
« Reply #3 on: June 17, 2008, 12:15:37 AM »
Ooo. Now I've just gotta get up the nerve to take a soldering iron to the 1200's board...

Thanks a bunch.
3 Commodore file cabinets, 2 Commodore USB turntables, 1 AmigaWorld beer mug
Alienware M14x i7 laptop running AmigaForever
 

Offline magnetic

  • Hero Member
  • *****
  • Join Date: Feb 2002
  • Posts: 2531
    • Show only replies by magnetic
Re: 1200 composite video interference fix?
« Reply #4 on: January 06, 2011, 02:36:39 AM »
tone

Did you ever do this mod? Anyone else?
bPlan Pegasos2 G4@1ghz
Quad Boot:Reg. MorphOS | OS4.1 U4 |Ubuntu GNU-Linux | MacOS X

Amiga 2000 Rom Switcher w/ 3.1 + 1.3 | HardFrame SCSI | CBM Ram board| A Squared LIVE! 2000 | Vlab Motion | Firecracker 24 gfx

Commodore CDTV: 68010 | ECS | 9mb Ram | SCSI -TV | 3.9 Rom | Developer EPROMs