[Coco] Yellow tinge

[Zippster]

Oh sure.  I only know with such certainty because I’ve encountered
it several times now.  It seems to be a fairly common problem with
older CoCo2’s at this point.

SWAG, I actually had to look that up…   :)

- Ed


> On Sep 13, 2017, at 7:59 PM, Gene Heskett <gheskett at shentel.net> wrote:
> 
> On Wednesday 13 September 2017 20:31:59 Zippster wrote:
> 
>> Really close Gene.  It is indeed related to color burst.
>> 
>> The “artifact” circuit in the CoCo2, which uses a 555 timer IC circuit
>> to pull on one of the color phases (causing the 1372 to generate a
>> pseudo color burst) gets out of tune, and pulls the phase lower for
>> too long.
>> 
>> This causes the yellow bar on the left.  I’ve also seen a bad diode in
>> this circuit constantly drag the phase lower than it should be,
>> causing a yellowish tint over the entire screen.
>> 
>> - Ed
>> 
> There is that possibility too.  I was offering a SWAG, as I have not 
> personally encountered the timer problem myself.
>