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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: Fizzy on February 12, 2007, 02:31:38 PM

Title: A1200 screen interference
Post by: Fizzy on February 12, 2007, 02:31:38 PM

Hi,

Dug out my spare 1200, and found that when using it, I get a little interference/noise on the screen when the disk drive is used, or when it clicks.  Also does it to a certain extent with the HDD.

I remember reading somewhere a while ago that this was a known issue and could be fixed be either removing or adding a cap somewhere on the board.  (its a revision 1.D if I recall correctly) I've hunted through aminet, spent a while trying to word internet searches to come up with something usefull, but can't seem to find anything.

Anybody happen to know where this info may be found?  

Thanks,

- Ian.

Title: Re: A1200 screen interference
Post by: AmigaSoft on February 12, 2007, 02:51:49 PM

As i recall its a condensator which probably needs replacing. This may be the cause of your problems but its not a job for a hobbiest it wants taking to a specialist to get the job done right.

Title: Re: A1200 screen interference
Post by: Doobrey on February 12, 2007, 03:20:29 PM

Quote

Fizzy wrote:
 I've hunted through aminet, spent a while trying to word internet searches to come up with something usefull, but can't seem to find anything.

http://aminet.net/package/hard/hack/flickfix (http://aminet.net/package/hard/hack/flickfix)  ;-)

Title: Re: A1200 screen interference
Post by: Jeckel on February 12, 2007, 03:23:09 PM

Actually, it's a known problem with rev 1D. A condensator is missing on this revision, you just have to add it and everything will be fine (I did the thing on mine some years ago).

Title: Re: A1200 screen interference
Post by: Fizzy on February 12, 2007, 03:49:30 PM

Thanks for the info guys.

Jeckel - when you say condensator, due you mean the same capacitor fix that Doobrey mentions?

I do have a reasonable amount of soldering skills.  I also have a spare non-working a1200 board.  Unfortunately none of the capacitors are marked with values.  Can anybody suggest a suitable c number to salvage off a 1A board?

Also the fix details off aminet do not give details of the orientation of the capacitor if you don't use a surface mount one.... or are they polarised too?

Title: Re: A1200 screen interference
Post by: Tomas on February 12, 2007, 03:52:27 PM

Does this happen on the rgb output as well?

Title: Re: A1200 screen interference
Post by: Fizzy on February 12, 2007, 04:01:07 PM

Yup - does it on rgb out too.  In fact this is when I noticed it - hardly ever use the tuner.. :(

Title: Re: A1200 screen interference
Post by: rkauer on February 13, 2007, 07:20:18 PM

http://www.aminet.net/hard/hack/flickfix.lha