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Atari A/V mod update

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I can't take it any more. I've tried to stay silent, and I mostly did so through the 8bitdomain debacle and now over a year of Longhorn's problems. But this is ridiculous.

 

Given that nobody can deliver on these mods, I have decided to make the CyberTech boards available again. To make it happen, I need to work out supply chain issues and my own lack of cash. But happen it will. And very soon.

 

I know this doesn't help the people who already ordered from Longhorn, but at least there will be a/v mods *readily* available again. Like I said, I don't have all the details worked out, so I'm hesitant to make promises at this point. (that way lies madness - as we all know). But I can say they will be very high quality, and priced to sell.

Glad to hear it, Chris! I was very impressed with the previous CyberTech mod. I hope you can work out a steady supply chain/distributor for it.

 

One of the reasons I've never updated my mods site, is due to the reports of people trying (and failing) to get 8bitdomain and LHE mods actually delivered. I haven't wanted to risk my own money ordering several mods just to have them never arrive, and even if they did, and I tested them, to what end would that do any good if other people couldn't get them?

 

I'm also looking forward to see what Fred comes up with. As he said, the more, the better.

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For all of you Jr. owners and Parker if your watching, in the instructions for the Jr. mod one picture shows the brown wire is to be soldered to the TIA chip:

 

DSCN3889.jpg

 

 

In the rest of the pictures it is soldered onto the board where a resistor once was:

 

DSCN3895.jpg

 

Which pic is correct?

 

 

Also finished a mod for a friend on a 4 switch, it has the color bleed problem mentioned long ago, was that ever corrected or is it still out there. If I remember correctly it was a delay with the luma signal?

 

Thanks in advance.

Edited by doyman

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For all of you Jr. owners and Parker if your watching, in the instructions for the Jr. mod one picture shows the brown wire is to be soldered to the TIA chip:

 

DSCN3889.jpg

 

 

In the rest of the pictures it is soldered onto the board where a resistor once was:

 

DSCN3895.jpg

 

Which pic is correct?

 

 

Also finished a mod for a friend on a 4 switch, it has the color bleed problem mentioned long ago, was that ever corrected or is it still out there. If I remember correctly it was a delay with the luma signal?

 

Thanks in advance.

Both locations for the brown wire are correct, since that pad for the removed resistor is connected to the same pin on the TIA the instructions say to connect to.

 

IIRC the issue with color bleed was the CD4050 causing too long a delay in the luma signal, and replacing it with a 74HC4050 reduced the delay/bleed significantly.

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Also finished a mod for a friend on a 4 switch, it has the color bleed problem mentioned long ago, was that ever corrected or is it still out there. If I remember correctly it was a delay with the luma signal?

 

Thanks in advance.

 

The mod doesn't completely eliminate the bleed. batari on the other thread passed the color through the 74HC4050 and got it to work. It is never going to be perfect due to the nature of composite and s-video signals (color phase) but batari got pretty close.

 

Parker

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Ugh broke the shell of my Jr. drilling with the Forstner bits. :x

 

I did the same with my 7800. At the time, I didn't know they made drill bits specifically for plastic that would probably be a better choice. :(

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I posted this earlier in the thread, but it seems worth repeating.

 

Running the drill bits in reverse worked exceedingly well for me. I used standard metal bits for the smaller holes and a wood boring bit for the bigger hole.

 

Running in reverse gently shaves the plastic away without any "bite" at all.

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Ugh broke the shell of my Jr. drilling with the Forstner bits. :x

 

You have to let the bit do the cutting and make sure to go evenly through the plastic. Even with specially purposed drill bits the plastic used on Ataris is very brittle and even more so that they are several decades old now.

 

Since I have switched to Forstner bits I have yet to crack an Atari case. Best part about them is that they don't chip the plastic on exit either.

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Yeah the 4 port we did was perfect, the Junior is so thin top to bottom so there just isn't that strong. I'm going to try epoxy and maybe some wood to beef it up. There is always fleabay.

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I always use standard old drill bits without any issues. The secret is just like LE mentioned the plastic is old and brittle. So I start with the smallest bit in my set and work my way up to the 1/4" for the composite holes then I use a bigger "hole" type bit I picked up at harbor freight for 5$ to drill the bigger hole for the S-Video. I usually use about 5-6 different bits stepping up each time and turning the drill slowly (its an old cordless with speed control). :D

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I always use standard old drill bits without any issues. The secret is just like LE mentioned the plastic is old and brittle. So I start with the smallest bit in my set and work my way up to the 1/4" for the composite holes then I use a bigger "hole" type bit I picked up at harbor freight for 5$ to drill the bigger hole for the S-Video. I usually use about 5-6 different bits stepping up each time and turning the drill slowly (its an old cordless with speed control). :D

 

That's what I did before I bought the Forstner bits. It always worked for me, too. Sure, it takes a little longer, but there's a lot less chance of damaging the plastic.

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Epoxy and less pressure did the trick last night. Now I just need to find my regular drill bits, and I'll be done with the Jr. On to the 7800 and that microscopic chip @ U5.

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Hmm for some reason I can not edit my previous messages....

post editing

 

Looking forward to the mod(s). :cool:

 

Thanks for that link! Good thing I thought I just couldn't find the silly edit button :D

 

I first dug up a old 4 switcher and took the TIA chip out. Stuck it in the 6 switcher and still the same faint vertical lines. So its not the TIA QC. Thankfully. I went back to the schematics of all 3 versions and my 4-switches I noticed that there are more then 1 circuit for the 4 switch models! The 4 switch I had modded was exactly like the 6 switch except no onboard CD4050 and a 1k resistor instead of the 680ohm for bridging the Blank and Color pins. So I swapped that 1k out for the 680 ohm and it looked just like the 6 switcher!

 

Tho this image is not perfect. There is some bleeding of colors (very slight but in sake of perfection I must figure it out). So I went back and disconnected the blank from the entire circuit. Heavy vertical lines on the screen but zero bleeding. Hmmm...

 

I decided to look at the Junior board because I got vertical lines but zero bleeding when I tested my mod on it. The Junior has a CD4050 and the blank pin added in. To my surprise the blank pin ran into the CD4050 along with the luma signals. This fact and the non bleeding colors without the blank line caused my "education" to finally kick in. "Maybe the CD4050 in my mod is causing a Delay in the luma signals which causes the bleeding when the non-delayed blank pin is feed in.", I thought. So I wired the blank line into the CD4050 on the mod and then through a 680ohm resistor to the color pin. And Bingo perfect vertical line less video.

 

So the V2.2 of the PCB and schematic will be posted on Saturday. With this discovery the mod installation will require some resistor leads depending on whether your Atari has the blank tied in or not. A little added complexity but It should only be 1 lead so it won't be surgery.

 

edit// OH pictures Saturday. I promise!

 

Ok I finished my Jr. and tested it. I am getting vertical lines much like you are talking about above. This is with composite video, I don't have S video. Did I miss a step in assembly?

Edited by doyman

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Did you twist the red wire (ground) and the composite wire (yellow) together? Also could you email me some photos of the install along with with the lines on the TV? I am assuming your using a stock Atari power supply and a good composite cable.

 

Parker

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Did you twist the red wire (ground) and the composite wire (yellow) together? Also could you email me some photos of the install along with with the lines on the TV? I am assuming your using a stock Atari power supply and a good composite cable.

 

Parker

 

 

Here is a pic of the installation 182679_10150102339623129_579353128_6416736_5514360_n.jpg

 

Here are the lines: 182435_10150102341968129_579353128_6416750_4117796_n.jpg

 

 

I did notice something when I plugged my daughter's vsmile back in. It has very similar vertical lines, though barely perceivable. SO it may be my stupid TV.

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Quick question... Parker uses 22AWG wire in this mod, is there any reason that 24AWG wouldn't work?

 

22AWG is used cause I can get 10 conductor wire (multi colors) for really cheap. 24AWG should be fine.

 

Parker

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I found a source with a ton of FMS6400s. Is there still a need for a redesign?

 

Do tell?

DigiKey has them in-stock. 1500 exactly, so maybe they recently got a reel of 2500 and sold 1000 of them to a customer.

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