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Cromemco dazzler replica project

Hugo, in your write up you talked about how the original design probably assigned the right resistor values to the wrong colors. I'm at the point where I need to decide if I use their original resistor assignments, or your updated ones? I don't mind doing the mod - especially if it yields better colors/greyscales. What are your thoughts?
 
nullvalue said:
Hugo, in your write up you talked about how the original design probably assigned the right resistor values to the wrong colors. I'm at the point where I need to decide if I use their original resistor assignments, or your updated ones? I don't mind doing the mod - especially if it yields better colors/greyscales. What are your thoughts?
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The resistors would need changing but also some tracks too. I decided to leave it as they designed it and regard it as one of the quirks of the original design. It doesn't really matter unless say you were starting with an NTSC color image and processing that to become a Dazzler image, vs say making either a color image or grey scale image from scratch. It is just a compatibility thing, for example if you program what looks like an NTSC test pattern, the luminance levels associated with each color doesn't match NTSC.

Photos of my boards attached. For the IC sockets which connects the two boards together, I used a blue type. These are a dual wipe design with gold plated contacts that have a very firm grip. At one point I had a lot of these nice sockets, but over the years worked my way through them. Now they seem relatively rare. The other sockets are genuine Augat types, I imported them from the USA for this board rather than using the modern clones. The sockets on the original board I think were the TI type which grab the pin over a small surface area from side to side, I was not keen to replicate those, because I have had a lot of trouble with that type in my SOL-20.
 

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Thanks! That makes sense, I'll just leave it original too then. Wow that's a fancy wiring job, looks really nice!
 
Beware of the TI closed frame sockets. It seems that they have been used for the early Dazzler designs. The contacts are 90° turned, so you have a minimum area of touch between the contact and the IC pin. They already have been unreliable in the times the boards have been produced, and quickly were drawn out of the market. Which is one of the reasons they are not available any more. I am using a special version of them in the Apple-1 replica, which is gold plated and works ok (unobtainium by the way). I recommend everyone to use precision, gold plated sockets like the Augat, and you have saved at least half of the testing & fixing efforts. Personally I am planning to use open frame sockets more close to the Rev D originals, but I am slightly masochistic in that point. Don't do that.
 
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Where is C42? I must be blind. I ordered it based on the manual, 330pF - but I can't find it on either board.

1709318869968.png
 
nullvalue said:
Where is C42? I must be blind. I ordered it based on the manual, 330pF - but I can't find it on either board.

View attachment 1274679
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This was mentioned earlier in this discussion - the Rev D board (vs the Rev C board that has been reproduced) included a couple of changes mentioned in Appendix A of the Games Manual for Dazzler board 2. This modification consists of a resistor/capacitor circuit added between IC50-12 and IC67-6 (R31 270 ohms and C42 330 pf).

Sorry for the poor quality of the scan - but this shows how R31 and C42 are wired between IC50-12 and IC67-6 on Rev D.

1709320792709.png
 
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Just to give you a little progress report on reverse engineering the source code for the dazzler library (and adding the comments) - it is going well and mostly making sense.

Onwards...

Dave
 
What are the odds of being able to use the library from a C program? ;) My assembly skills are novice-level at best.
 
Hi, When the reproduction boards are finalized and working then the software development starts ... I hope somebody can create a dial-up game where two people can either be adversaries in a maze or partners against the computer generated maze and characters ... maybe something like a dial-up CATCHUM or LADDER ... it might be a little slow, but I think it would be a neat step for the S-100 buss systems.

.
 
A multiuser 3D maze would be good.

The maze can be randomised and people placed at random locations in the maze when the game starts.

You then have to escape the maze.

The question then becomes what to do when you see other people, and should there be treasure to collect along the way?

Dave
 
Another crazy idea I had a few days ago.. TI-calculators for the most part have Z-80s and heck, even Doom has been ported to it. The TI's resolution of 64x96 would easily fit in the Dazzler's mode 2 128x128. There's a huge library of TI games that could potentially be ported..
 
hmb said:
This was mentioned earlier in this discussion - the Rev D board (vs the Rev C board that has been reproduced) included a couple of changes mentioned in Appendix A of the Games Manual for Dazzler board 2. This modification consists of a resistor/capacitor circuit added between IC50-12 and IC67-6 (R31 270 ohms and C42 330 pf).

Sorry for the poor quality of the scan - but this shows how R31 and C42 are wired between IC50-12 and IC67-6 on Rev D.

View attachment 1274681
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@hmb would be nice to have the full Rev D schematics. There are a couple of other changes on the second board Rev D layout which require check against the schematics (probably mostly changes in the routing), but I couldn' locate the Rev D schematics yet.
 
Ansgar Kueckes said:
@hmb would be nice to have the full Rev D schematics. There are a couple of other changes on the second board Rev D layout which require check against the schematics (probably mostly changes in the routing), but I couldn' locate the Rev D schematics yet.
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Unfortunately the schematic in the scanned copy of the Rev D manual that I have is almost illegible - the small section I reproduced above shows just how bad it is.
 
I will check the Cromemco repository tomorrow to see if there is something in there...

Has anyone already checked?

Dave
 
daver2 said:
I will check the Cromemco repository tomorrow to see if there is something in there...

Has anyone already checked?

Dave
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Yes - the Rev D manual copy I have, with the illegible schematic, is from the Cromemco repository.
 
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