Re: Static PET PSU questions

From: André Fachat <>
Date: Mon, 12 Oct 2009 13:27:26 +0200
Message-ID: <>
-------- Original-Nachricht --------
> Datum: Fri, 2 Oct 2009 02:36:23 -0400
> Von: Ethan Dicks <>
> An:
> Betreff: Re: Static PET PSU questions

> Well if there were display frequency changes between the 1977 PET and
> the 1978 PET, then I can entirely understand what I'm seeing on the
> display.  Obviously there were changes between the 4032 and the 8032.
> I had no idea there were changes between 40col boards.

The changes between the 4032 (with CRTC) and 8032 (with CRTC) are only on the side where the data is sent out pixel-wise. In the 8032 there are 16 pixels shifted out in the same time as 8 pixels in the 4032. 
Even the counter values in the CRTC are the same between the 4032 and 8032. Only instead of a single byte in the 4032 two bytes are read in one clock phase in the 8032.

So I _think_ you should be able to interchange the 4032 and 8032 monitors as they should be using the very same timing.
There might be other differences I do not know though.
And that seems to be different with the non-CRTC PETs, as I read here.

> So... trying to keep within the designations as I understand, I have
> been trying to use a Static PET board with a 9" Dynamic PET (but not
> "Universal PET").  If that combination is incompatible, then there's
> probably nothing left to test in the video circuit of the static PET
> (and it makes me wonder about the universality of the
> simple-TTL-gates-and-passives composite converter circuit that's been
> knocking around for 30 years).

I used such a simple converter on my selfbuilt computer which is modeled after a CRTC PET, and uses basically the same timing. I successfully use it to drive a normal PAL TV.

Were those converters already used for the static PET?

> Thanks for any clarification
> -ethan
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Received on 2009-10-12 12:00:04

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