Cromemco dazzler replica project

[nullvalue]

2. Remove ICs 47 and 55 from the Dazzler. Insert some temporary wires into the following pins of IC socket IC55 and connect them to 0V: pins 11, 6, 3 and 14.

So leave 47 removed, and just insert the temp wiring on 55, correct?

 

[daver2]

Correct.

Leaving 47 out will cause the associated outputs to float high (as a result of the IC inputs they are connected to).

Wiring the outputs of 55 to 0V causes them to be low.

All high pins = white. All low pins = black. I hope...

Dave

 

[nullvalue]

Probably not the rig you were expecting, but should get the job done

 

[daver2]

That is inspired...

If this works, we can make good use of that!

Dave

 

[nullvalue]

Success?

 

[daver2]

Yes!

Now can you change D5=1.

This should double the resolution.

 Dave

 

[daver2]

I have to do the washing up now...

Dave

 

[nullvalue]

Now can you change D5=1.

This should double the resolution.

Yep it does, it doubles the number of vertical lines.

 

[daver2]

It should also double the number of horizontal lines - but you won't be able to see that.

Give me a few minutes to finish up in the kitchen and we will try a few other things...

We can have some fun now!

Dave

 

[daver2]

Can you set D7 to D0 as follows (using my test program):

0011 1001

In theory, the display should not change from what it is now.

Dave

 

[nullvalue]

Can you set D7 to D0 as follows (using my test program):

0011 1001

In theory, the display should not change from what it is now.

Dave

It does not change, still double resolution. The only thing I noticed is setting D4=1 is the lines get very slightly brighter, or potentially like 1 pixel wider.

 

[daver2]

I can't get too excited about that...

Now set D6=1 and let's see what happens next (or not)...

Dave

 

[nullvalue]

Now set D6=1 and let's see what happens next (or not)...

Previously when playing around D6=1 would blank the whole screen.

But in this setup it leaves some dim lines:

 

[daver2]

Well, that should be red - but it looks sort of like cyan/blue to me - but I am green/blue colour blind!

Try various combinations of D2, D1 and D0 from 000 (should be black) to 111 (should be white). The bits 'should' be in the order D2=blue, D1=green and D0=red.

See if you see any difference. We may still need to tweak the colour potentiometers, but don't do that now!

Dave

 

[nullvalue]

I get no color at all, just varying levels of white. The thin lines may be slightly blue, but could just be an artifact of my monitor.

Some combinations appear to break the lines up..

like this 0111 1101:


or with D5=0 (0101 1101)



Tried this with 2 known good/working color composite monitors & cables.

 

[daver2]

Hang on a minute, you are adjusting D7 to D0 in my test program and not the wires connected to IC47 and IC55 aren't you?

Dave

 

[nullvalue]

Hang on a minute, you are adjusting D7 to D0 in my test program and not the wires connected to IC47 and IC55 aren't you?

Yes adjusting the outputs through the test program, not modifying the wires.

 

[daver2]

OK,

Can we do one more test then for tonight.

Set D7 to D0 in my program back to:

0010 0000

Post a photograph.

Then we will tweak some wires next.

Dave

 

[daver2]

Next...

Leave IC47 with no wires on it and remove the wires from IC55 pins 11 and 14.

Post another photograph.

Then set D4=1 using my test program.

Post another photograph.

Dave

 

[nullvalue]

00100000: