Improved Color For Your 4-Switch Woody: A Public Service Bulletin

[Andromeda Stardust]

Another option if you can't procure an 820ohm resistor, is to use a 1k in parallel to a 4.7k. This results in a value of roughly 824 ohms, well within 1% tolerance. I remember shopping at Radioshack and making one since they did not carry that value. A fellow AA member later shipped me a metal oxide 820 ohm (blue epoxy) in an envelope free of charge so I used that instead of the parallel carbon film (beige epoxy) I made from RS.

[+H454]

Another option if you can't procure an 820ohm resistor, is to use a 1k in parallel to a 4.7k. This results in a value of roughly 824 ohms, well within 1% tolerance. I remember shopping at Radioshack and making one since they did not carry that value. A fellow AA member later shipped me a metal oxide 820 ohm (blue epoxy) in an envelope free of charge so I used that instead of the parallel carbon film (beige epoxy) I made from RS.

 

Ah, yes, how many of us have gone to radio shack to not find what need and having to cobble something together.

Its almost a shame a new generation won't have that experience.

 

I think the higher value, the higher the color intensity - you could use probably any thing from 600k to 900k without any problems.

Think I read of someone suggesting a 1000K potentiometer and find tune to your liking.

[Andromeda Stardust]

 

Ah, yes, how many of us have gone to radio shack to not find what need and having to cobble something together.

Its almost a shame a new generation won't have that experience.

 

I think the higher value, the higher the color intensity - you could use probably any thing from 600k to 900k without any problems.

Think I read of someone suggesting a 1000K potentiometer and find tune to your liking.

But how would we learn if it weren't for cobbling stuff together to see what works? Ohm's law doesn't lie, you know...

 

I imagine if adding a resistor when none existed before increases the color intensity, by comparing the resistance before (infinite???) and after (820ohm), that decreasing the resistance would increase the saturation to the point where it becomes garish or worse, clips the color channels. Zero resistance would likely burn something out, but perhaps a smallish value in series with a 1k pot and you could have some fun dialing it in.

[atari-dna]

Can someone post a pic of Video Pinball running on a modded machine?

I can provide a Video Pinball screenshot with the resistor update [emoji4]

 

 

Sent from my iPhone using Tapatalk

[atari-dna]

Can someone post a pic of Video Pinball running on a modded machine?

Here’s Video Pinball on a rev 12 board with the resistor added. Picture is RF.

 

 

 

Sent from my iPhone using Tapatalk

[MaximRecoil]

 

FYI, I performed the 820ohm resistor mod sometime last year '15 or '16, can't remember, but it was fall. i do not regret it. Makes the colors pop!

 

 

Another option if you can't procure an 820ohm resistor, is to use a 1k in parallel to a 4.7k. This results in a value of roughly 824 ohms, well within 1% tolerance. I remember shopping at Radioshack and making one since they did not carry that value. A fellow AA member later shipped me a metal oxide 820 ohm (blue epoxy) in an envelope free of charge so I used that instead of the parallel carbon film (beige epoxy) I made from RS.

 

Yeah, it was the fall of 2015 (October). I mailed you the resistor shortly after I did the modification myself:

 

 

And it definitely makes a big difference:

 

Before:

 

 

After:

 

 

And for comparison:

 

Light Sixer:

 

 

Atari 7800:

 

 

The 6-switch models still have the best color, but it is still a big improvement for the 4-switch model nonetheless. Plus it is an easy modification to do, and practically free.

Edited March 8, 2018 by MaximRecoil

[atari-dna]

After reviewing the schematics and revisions of 2600 hardware, I’ve noticed something peculiar about this bulletin that Atari circulated.

 

Summary: The color output is tied to the blanking line with a resistor in a heavy 6, and later this was dropped (cost reduction?) then made available as an upgrade due to poorer color reproduction—finally the blanking resistor was incorporated back into the design.

 

Here’s what is strange. The value of the resistor which was originally in circuit (heavy 6 R213) is 680 Ω the “update” stipulates an 820 Ω be inserted, which is about 20% greater resistance.

 

Aside from that, all the other parts of this circuit are identical. So, why the boost on the resistor?

Has anyone tried an 820 on a heavy? Or using a 680 on a 2600A?

 

I wonder if there is a significant difference? I’ve always liked the color quality of the heavy and found the juniors also pleasing to the eye. Now I am tempted to compare and contrast the two while swapping the blanking resistor values. I’m interested to know which produces better color? Possibly a 1K pot could be dropped in there and tweaked to see if there is a “sweet spot”?

 

Has anyone tried experimenting with this? Please let me know.