[Coco] Program for test pattern for crt alignment/convergence?

[eric at canales.me]

I wouldn't use a coco calibration tool. The issue with the CoCo is it's not
particularly designed to give you an accurate picture and resolution that
fills the entire tube. 

What I'd suggest is instead hook up a nice DVD player to the monitor, and
then use a standard calibration DVD to generate the patterns. Spears &
Munsil is quite good:

https://www.amazon.com/Spears-Munsil-High-Definition-Benchmark-Blu-ray/dp/B0
0UGQ8GEU/ref=tmm_dvd_swatch_0?_encoding=UTF8&qid=1659982222&sr=8-1

Make sure to get the DVD version if you're using composite, or get the
bluray if your bluray player has a good composite out. If you try to
downconvert and HD signal you'll also be calibrating for your down
converter, which tbh probably wouldn't be a big deal for use with the CoCo.

One day I want to make a calibration tool for the CoCo but it's going to
require quite a bit of testing, trying out various models of monitors and
CoCos, and it's just much simpler to use a DVD player which is made to give
you the most accurate picture it can.

-----Original Message-----
From: Coco <coco-bounces at maltedmedia.com> On Behalf Of Don Barber via Coco
Sent: Monday, August 8, 2022 11:28 AM
To: coco at maltedmedia.com
Cc: Don Barber <don at dgb3.net>
Subject: [Coco] Program for test pattern for crt alignment/convergence?

Hi folks, acknowledge I'm sending a lot to the list recently but I got a lot
of projects going on.

I'm replacing the tube of a Commodore 1084S-D1 when the old crt tube 'let
the vacuum out.'
I've got it aligned pretty close by eye but to get it exact I'd like a
proper test pattern, like white-on-black grid lines to get it just right.
I've already soldered up the cable to get this monitor working on the coco
so was hoping to be able to generate such a test pattern from the coco.

As such, anyone know of a coco program to generate decent test patterns,
specifically a grid / cross-hatch pattern?

I found Coco Color Bars (
https://colorcomputerarchive.com/repo/Disks/Demos/Coco%20Color%20Bars%202020
%20(Jason%20Reighard).zip
) which is awesome - but still looking more for the grid test pattern. 
Figure I could probably whip something out in basic without much effort but
thought maybe someone would know of an existing one?

Alternatively I could probably get a CGA cable together to hook up this
monitor to an early PC if someone has an early dos program to generate a
test pattern.

Don


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