Re: TED badlines, how do they work?

From: Gerrit Heitsch <>
Date: Sun, 04 Sep 2011 19:16:38 +0200
Message-ID: <>
On 09/04/2011 06:31 PM, Segher Boessenkool wrote:
>>>>>> After all, the 656x-VIC-II still needed +12V for parts of the chip
>>>>>> (video output drivers?) where TED managed the same with a single +5V
>>>>>> supply (and produced more colors).
>>>>> The power supply for the (analog) output stages, yeah. 8565 uses 5V as
>>>>> well, I'm not sure why the 6569 needed 12V.
>>>> No idea either... But I have a C64 with a 6569R3 (in ceramic :)) where
>>>> the +12V supply was broken. Due to a dead capacitor the VIC only got
>>>> +8V. I still got a picture, but the colors were pale and went
>>>> completly away when the chip warmed up, giving a pure B/W picture.
>>>> Otherwise the system was working fine. Replacing the dead capacitor
>>>> restored +12V and fixed the color issue.
>>> Would be interesting to know whether amplifying the output would have
>>> helped as well :-)
>> LUMA was OK and didn't change after fixing the +12V supply. Just for
>> fun I measured power consumption on +12V for the 6569R5 (4786 15) on
>> my testboard. It draws 34-35 mA on +12V alone.
> It turns out the (internal) clock drivers and a few other things use the
> 12V
> supply on the 6569 (those use the normal supply on the 8565). Those can
> sink
> a lot of current I bet ;-)

Makes me wonder why they did that. Needed +12V for the dotclock and 
color clock to work properly? The power comsumption on +12V helps 
explain why the 6569 runs so hot. Without a heatsink you'll burn your 
fingers on it. Still, it doesn't seem to mind. TED and the 8501 don't 
get as hot by a long shot but are still more prone to die. :(


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Received on 2011-09-04 18:00:10

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