Re: PET 50Hz editor ROMS

From: Marko Mäkelä <>
Date: Fri, 8 May 2015 22:21:49 +0300
Message-ID: <20150508192149.GB1502@x220>
On Fri, May 08, 2015 at 04:51:47PM +0000, William Levak wrote:
>>For minimal interferences only the vertical sync is defined to the 
>>frequency of the main power.
>I looked at the schematics for the vertical drive circuit.  It is 
>driven entirely from 12 V DC and the sync signal from the system 
>board. So, it would not be affected by different line frequency.

I think that Martin meant interference between the CRT display and 
ambient lighting, such as fluorescent tubes or tungsten bulbs. I do not 
know, but it might be that the screen would seem to flicker if the 
lights flickered at 50Hz (or 100Hz) while the screen is flickering at 

I have seen how fluorescent tubes can cause flicker for a digital video 
camera (modern DSLR that supports video recording) at certain shutter 
speeds. But I guess my eyes are too slow to notice.


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Received on 2015-05-08 20:00:06

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