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RF addendum


Nathan Strum

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In my previous entry about improving RF on a 2600, I mentioned that I wanted to try two additional changes:

  1. A different, more flexible RF cable
  2. A different F-type to RCA adapter

So, I made those changes! And now I'm blogging about them! Exclamation points!!

 

(I figured a new blog entry would be better than trying to squeeze all of this into the other entry's comments.)

 

For the cable, I went with another cable from Blue Jeans Cables, this one using Belden 1505A coax.

 

The 1505A (in the middle) is a lot more flexible than the previous Belden cable I got from them (on the right), and is also more flexible than the cheap Cable Matters ones I got from Amazon. The original Atari RF cable is on the left:

 

new-cable-comparison.jpg

 

So, how does it work? Well, the picture quality is every bit as good as the previous, heavier cable:

 

belden1505a-chopper.jpg

belden1505a-pitfall.jpg


belden1505a-si.jpg

 

That said, you still need to keep it away from sources of RF interference. In this case, the 2600's AC adapter:

 

belden1505a-noise-chopper.jpg


belden1505a-noise-pitfall.jpg


belden1505a-noise-si.jpg

 

So I'm definitely going with the 1505A cables from this point on. For my 7800, I'll be ordering one just a couple of feet long, because that console sits right above the Sony tuner I plug it into.

 

For the new adapter, originally I used an F-type to RCA adapter, plus two right-angle RCA adapters. This was necessary to route the cable where I needed to plug it in:

 

rca-adapters.jpg

 

The new adapter (on the left, from Max-Gain Systems) is an F-type to RCA right-angle adapter. So this replaces two of the previous adapters:

 

new-adapter-compared.jpg

 

You can find similar adapters on Amazon, but I went with this one because the center post is already shortened. So if you have a 2600 where you can plug this in directly, you don't need to file down the post. (Different revisions of the 2600 used different RF modulators, and the locations of the RCA jacks varied.)

 

With the previous adapters, the RF cable couldn't bend before hitting the back of the 2600's case:

 

old-rf-adapter-test-fit.jpg

 

But with the new adapter, it gains that crucial extra space:

 

new-rf-adapter-test-fit.jpg

 

If you'd read my previous couple of blog entries, you'd know that I've been running all of these RF tests in a 2600 "Vader" that John Champeau sent to me to repair (along with another console).

 

The original problem with this console was that the joystick control always moved right. Always. Whether there was a joystick plugged in or not. So I desoldered and socketed in a replacement RIOT chip, and that solved that issue. I also installed a refresh/cap kit from Console5. (BTW, if you're wondering where the caps should go, mojoatomic posted instructions here.)

 

With the console working again, I figured I'd work at improving its RF output, and get a couple of blog entries out of it in the process. :) 

 

To install the new RF cable, I had to modify the 2600's case very slightly. I had to enlarge the hole for the original RF cable by a couple of millimeters. Just enough for the connector to fit through.

 

widened-hole.jpg

 

To make the connector fit through, I had to slide the strain-relief boot down the cable:

 

rf-boot-loose.jpg

 

Fit the connector through the case:

 

rf-through-hole.jpg

 

Then squeeze the boot through:

 

rf-and-boot-through.jpg

 

The cable exits through the main hole. To make it fit through the original RF cable's notch (next to the hole), I would've had to file the notch out a lot more, and I didn't want to risk breaking the plastic.

 

installed-cable-outside.jpg

 

With the cable through, I attached the two adapters, wrapping electrical tape around the RCA connectors, so they wouldn't come apart:

 

new-rf-routed.jpg

 

Then I positioned the circuit board, and plugged the cable in (I checked the angle before taping the RCA connectors):

 

new-rf-installed-2.jpg

 

Then, I brought the two halves of the case together. You can see how little space there is above the adapters:

 

tight-quarters-side.jpg

 

In fact, they touch the top part of the case. But there is enough room for them!

 

tight-quarters-front.jpg

 

And with that, and a bit of a clean-up, the Vader was all ready to be packed up and shipped off!

 

jwc-vader-finished.jpg

Well... almost. :roll: 

 

After getting it back together, I thought I should go through and test everything. I knew that joysticks worked, but I wanted to make sure everything else worked - paddles, an AtariVox, etc.

 

So I plugged in some paddles, and... nothing. I tried them on TestCart, Warlords, Medieval Mayhem... nothing.

 

I pulled the RIOT and tested it in another 2600. Everything worked fine there.

 

So I desoldered and socketed in a new TIA. And that fixed the problem. (BTW, if you do much in the way of console repair, I can't recommend getting a proper desoldering gun highly enough. I used to own a cheap little Radio Shack one, and while it worked, the Hakko one I have now is much faster, much safer, and does a much better job.)

 

And with that, the console is finally back together, fully tested and working, and ready to go.

 

Next time, I'll tell you a little bit about the other console John sent me, what had to be fixed on it, and the best cleaning tip you've ever heard in your entire life!*

 

 

*Note: May not be applicable, depending on how many cleaning tips you've actually heard about in your entire life.

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BTW, if you do much in the way of console repair, I can't recommend getting a proper desoldering gun highly enough

So true. The one I have a is a just chinese desoldering station, so the build quality and duration are not comparable to a good brand tool like the one you linked, but I had it for a few years now, and considering that I paid about 70 EUR for it, I can't complain. (it's the same as the one in this EEVBlog video, that is sold with various different brands and costs about 80 EUR shipped right now in Italy from ebay).

Despite the cheap construction, It works great and I would instantly buy another one in case it would break. I cannot go back to a solder sucker and desoldering braid.

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These are awesome reads @Nathan Strum, thank you :D I'm gonna upgrade my RF, and in planning, opened up my light sixer to check the space (looks to be plenty of room for the new setup). But when I opened it up, I was surprised to see this...

 

Notice the PAL sticker next to the RF port...

insidemyatari.thumb.JPG.7d60c261960bbf9477757c550fd80c7f.JPG

 

I live in the United States... I got the system as a gift, which was bought off eBay in maybe 2000, and there's no way it wasn't a domestic purchase since shipping the huge console center and games I got with it would've cost a ton. That said, I have no idea where it came from before me. But basically, do you know what that PAL sticker is all about? I've been playing it on my regular NTSC CRT TVs for the past 2 decades, using NTSC carts, and everything seems fine to me. I'm thinking that it does not mean that my system is actually PAL, but I'm confused...

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Interesting... I suppose someone could've moved here with it and it ended up in an eBay lot. If it wasn't PAL, I don't know why the sticker would be there. I suppose it could've been repaired or factory refurbished at some point and the wrong label ended up on the wrong part.

 

There's a thread about this sort of thing here: 

 

The consensus seems to be that the games will run fine, but the colors will be wrong. I'd suggest running games that you own in Stella, switching palettes between NTSC and PAL, then seeing what the games look like on your console. That should tell you what the console actually is.

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Thanks for the info! I have noticed some different coloring from when I play something on my system vs on an emulator. That is super interesting...I could've been working off a PAL system this entire time. I hope that's not the case, since it looks like from that discussion, that NTSC on a PAL system and an NTSC TV might result in a slightly faster game ?

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Thanks for the info! I have noticed some different coloring from when I play something on my system vs on an emulator. That is super interesting...I could've been working off a PAL system this entire time. I hope that's not the case, since it looks like from that discussion, that NTSC on a PAL system and an NTSC TV might result in a slightly faster game ?

 

Update: Checked NTSC vs PAL on the emu, and I am definitely running NTSC colors on my console. So that's good, but also kinda odd about the pic. Hmm,

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Nathan, thank you for all of this information!

 

Previously I used an RCA-to-coax connector, a cheap VCR, and cheap cables. It was noisy at best, and the connections required frequent attention. On your advice I bought a dedicated tuner (the same Sony model you mentioned) and 2 cables from Blue Jeans: one RF from Atari to tuner, one composite from tuner to monitor, both Belden 1505A. Together they are a *huge* upgrade, stable and noise-free to my eyes.

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