what Hz is my monitor after a VGA 640 X 480 upgrade?

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Joined: May 9 2015
Posts: 62

Hi folks....

Reading the CC FAQ here, lead me to Chris Lawson's VGA 640 X 480 mod for the Color Classic. I was reading this page:

http://www.colourclassicfaq.com/general/vga.html

I read it over and over, and I could not figure out what the Hz of my monitor would be after doing this mod. Can someone tell me? Is it 60Hz?

jack the new kid

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eeun's picture
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Joined: Dec 19 2003
Posts: 1891
Re: what Hz is my monitor after a VGA 640 X 480 upgrade?

With Chris' modifications, the monitor remains at 60Hz. I did the mod on one of my previous CCs, and it looked great. The flicker was minimal enough to forget it was there.

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Joined: May 9 2015
Posts: 62
Re: what Hz is my monitor after a VGA 640 X 480 upgrade?

Thank you EEM.....

Some say that raising the voltage from 60V (which it was designed for) to 68.4V (after doing the VGA mod) will shorten the life of your Color Classic.

What is your opinion?

jack

eeun's picture
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Joined: Dec 19 2003
Posts: 1891
Re: what Hz is my monitor after a VGA 640 X 480 upgrade?

I did my first CC with the VGA mod, and when Chris posted the 60Hz mod I did that for the next, taking his advice that it was a bit less stressful for ageing components.
But I didn't own either machine for much more than a year so couldn't tell you if one is truly better in the long run.

My current CC is staying stock.

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Joined: May 9 2015
Posts: 62
Re: what Hz is my monitor after a VGA 640 X 480 upgrade?

Thanks for your email eeun.

I work with a fellow on restoration of old time vacuum tube motion picture amps. In real life, he works for a company that works for TV stations all over the world. My engineer buddy is sent all over to solve video issues. Then he comes back to the US, designs a circuit, then the company he works for will develop a card or box for users (TV stations, governments, etc).

I ran the Mystic upgrade up the flagpole with him. He told me that when new, and if you had industrial, TV station equipment behind it, you could push that Sony CRT plus or minus about 5% and get away with it for a little while. But putting 68V or 69V on pin 8, in a old, consumer grade environment, was asking for trouble. He advised me to move to the CC II board and call it good.

I think I am going to follow his advice. I may do the software mod so I can run a 575 logic board, but if I understand that mod correctly, I am still leaving 60V on pin 8 and the computer will still display 560 x 384 pixels.

This sounds much safer to me.....

jack

Dr. Webster's picture
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Joined: Dec 19 2003
Posts: 1687
Re: what Hz is my monitor after a VGA 640 X 480 upgrade?

Considering how old the components are (and how hard it would be to find replacements), I wouldn't do any sort of screen mod. These machines are also starting to become even more rare (they weren't exactly common to begin with). Like eeun, my own CC is staying stock.

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