English

There  are  annoying  thing  on some new (ESCOM AG) AGA machines - strange
video  effects,  caused  by  a bug in video controller.  It are flickering
stripes,  what  appear  progressively  on  the 28mhz (PAL shres, Multiscan
hires)  screen  during  electricity warms the machine.  It appears only if
RGB   color   (24bit)   have  23-24bit  set  -  e.g.   RGB=255,255,255  or
RGB=255,255,127.  Most programs have palette preferences and colors can be
setting   in  any  values,  but  some  programs  (e.g.   picture  viewers,
ShapeShifter, etc.) haven't this option.

There  are  several software solutions - programs for correcting colors on
the  screens,  but  these  programs  trashes  palette  and  don't  work on
non-system stuff.  It is not very effectively...

Now we have very effective hardware solution.  Simply connect together two
pins of resistor E127R on A1200 board.

Big thanks to Alexander Bogdanow for info.


Russian

     Ìíîãèå  ïîêóïàòåëè  «íîâûõ»  1200òîê  (îò 
ESCOM  AG, à íûíå îò AMIGA
Technologies)  ñòàëêèâàëèñü  ñ íåïðèÿòíîé
ïðîáëåìîé:  ïîÿâëåíèåì ìåðöàþùèõ
ïîëîñîê  ñïðàâà  îò  íàèáîëåå  ÿðêèõ  öâåòîâ 
íà  ýêðàíå â 28-ìåãàãåðöåâûõ
ðåæèìàõ  -  òàêèõ,  êàê  Multiscan  hires  èëè  PAL
superhires.  Ñóòü ýòîé
ïðîáëåìû  â  äàííûé  ìîìåíò  óæå  èçó÷åíà  - 
ýòè  ïîëîñêè  íà  ñàìîì äåëå
ïðîÿâëÿþòñÿ  íå  íà íàèáîëåå ÿðêèõ öâåòàõ, à
íà öâåòàõ, â RGB ñîñòàâëÿþùèõ
êîòîðûõ ïðèñóòñòâóþò õîòÿ áû 23 áèòà.  Ýòî
çíà÷èò, ÷òî ýôôåêò ïðîÿâèòñÿ íå
òîëüêî  ïðè  RGB=255,254,255,  íî  è  íà  RGB=255,255,127.  
Ñêîðåå âñåãî,
ïðè÷èíà  ýòîãî  â  òîì,  ÷òî  ïðè  áîëüøîì 
êîëè÷åñòâå  åäèíèö íà öèôðîâîé
âèäåîøèíå  ïðîèñõîäèò  ïåðåãðóçêà 
ìèêðîñõåìû ïî ïèòàíèþ, èëè ÷òî-òî åù¸ â
ýòîì æå äóõå.
     Ïðîñòåéøèé ñïîñîá ðåøåíèÿ ïðîáëåìû -
çàìêíóòü ðåçèñòîð E127R ñ íèæíåé
ñòîðîíû  ïëàòû  ìàøèíû  (ïðè  ýòîì  ïðèä¸òñÿ 
ñíèìàòü  ñ íå¸ ìåòàëëè÷åñêèé
êîæóõ).  Íà ðèñóíêå â àðõèâå óêàçàíî
ïðèìåðíîå åãî ðàñïîëîæåíèå.  Ïðè ýòîì
ñîîòâåòñòâóþùèé  ñèãíàë  ïîäà¸òñÿ  íà  âõîä
ìèêðîñõåìû LISA ñ âûõîäà ALICE
íåïîñðåäñòâåííî, ìèíóÿ «àíòèçâîííûé»
ðåçèñòîð.  Íàçíà÷åíèå ýòîãî ðåçèñòîðà
-  ïðåäîòâðàùåíèå  ýôôåêòîâ,  îïèñàííûõ 
âûøå.   äàííîì ñëó÷àå ïîëó÷èëîñü
íàîáîðîò.   Êàê  ìíå  êàæåòñÿ,  åñëè  áû  24
òî÷íî òàêèõ æå ðåçèñòîðà áûëè
óñòàíîâëåíû íà âèäåîøèíå, ïðîáëåìû áû íå
áûëî.
     Àëåêñàíäðó   Áîãäàíîâó   çà  
ïðåäîñòàâëåííóþ  èíôîðìàöèþ  âûðàæàåòñÿ
èñêðåííÿÿ áëàãîäàðíîñòü.

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[generic]                 1450    2382  60.9% -lh5- a86e Sep 29  1997 flickerfix.doc
[generic]                  315    3890   8.1% -lh5- 1bd3 Sep 29  1997 flickerfix.ilbm
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