(Insert stupid Blog name here) - Three chips off the old block

RSS Bot · March 3, 2017

Keeping an old 2600 running isn't always easy...

My original 2600 is kind of an odd one to begin with, in that it was a factory reconditioned Sears console, with a light-sixer case, but heavy-sixer insides. Apparently, this is just something Atari did. It makes sense - if they're factory-refurbishing something, they'll put it back into the best, or newest, case available.

In 2002, as I dusted off my 2600 for the first time in years, I noticed the springs in the switches were broken. These were the chrome-capped switches Atari used when reconditioning their consoles, although I didn't know that at the time. I thought they were just stock switches. So I ordered some replacements, only to find out they were the aluminum-finish ones instead. I was disappointed, but installed them anyway. In hindsight - I would have disassembled them, and kept the chrome switches, just repairing the springs.

In 2008, my 2600 died. In that case, it turned out to be the hex buffer (CD4050) - which was a pretty easy fix. Thanks to batari and supercat who suggested that was the problem.

Then, in 2011, it died again. This time though - I couldn't get it working again. I wasn't sure what the problem was, although the console had taken a lot of abuse over the years as the guinea pig for my mods comparison tests. I tried swapping chips with a working four-switch Vader, to no avail. Meanwhile, I used the Vader as my daily driver.

In 2015 I bought a populated six-switch donor board from Best Electronics to swap parts with, in an attempt to get my original console working again. But despite my "best" :roll: efforts - my original 2600 just wouldn't work. Its TIA was good though, since that worked in the donor light-sixer. But its 6507 and RIOT wouldn't work, so I figured those were bad. But even swapping all of the donor's chips over to my 2600 didn't get that working.

So then the donor board went into my original 2600's case, "fixing" it. But it wasn't really fixed, and I still really wanted to get as much of my original 2600 working as possible.

Then recently, mojoatomic began selling capacitor and voltage regulator kits. Now, these parts can be found at Digikey or Mouser, but the nice thing about buying his kits, is that he buys them in bulk, and saves you the trouble (and shipping costs) of hunting them down yourself. Everything's just there in a neat little bag. Plus, he posted instructions on what to replace. And he also sells brand-new replacement power adapter jacks. Very nice!

So, hoping this might have been part of my original 2600's problem, I ordered up some kits and installed them.

But again, to no avail. Swapping the chips with the donor light-sixer still didn't fix it.

Mojoatomic also suggested checking for cold solder joints and bad connectors on the IC sockets or cart connector.

So, I spent a pretty long evening desoldering and replacing the IC sockets, and completely re-soldering the cart connector.

Still nothing.

At this point, I was about to give up and take up mojoatomic on his offer to see if he could fix whatever was wrong. But first, I tried one more thing.

I pulled the RIOT and 6507 from the Vader again, and popped those into my original heavy board.

And it worked! My Atari was back! For realsies, this time! :-D

So what happened, and why didn't the donor-sixer's chips work in my board? They worked in the light-sixer, and the chips are all the same, right?

Well... not exactly.

Since I first got the donor board, it always had a slightly odd quirk. It worked fine, but whenever I pressed the fire button on the joystick, the picture would dim slightly.

I had hoped recapping and replacing the voltage regulator on the donor would fix that problem. But it didn't. Yet - the console still worked. So I assumed its chips all worked.

But apparently, the RIOT is going bad. It's not bad enough to fail on the light-sixer, but it is on the heavy. So I was trying to troubleshoot using a bad chip. :roll:

Once I put the Vader's RIOT into the donor-sixer, the dimming problem went away.

I think the sequence of events went like this:

My power adapter had some sort of problem. When it did, it took out my original console's RIOT and 6507. (That power adapter has - quite recently - fully up and died. So I'm sure now it was the culprit.)

It may have also taken out the voltage regulator or a cap somewhere. This would explain why originally transplanting the Vader's chips didn't work.

It may have also damaged the donor light-sixer's RIOT, causing the dimming problem. But I have no way of knowing that.

In the end, I had a bad 6507, and two bad RIOTs.

But now I have two re-capped 2600s with new voltage regulators and power adapter jacks, and I know they both work. I'm going to go through and upgrade my Vader and another four-switcher I have with those kits as well.

I've ordered up the replacement chips I need from Best, as well as a few other goodies (power supplies, joystick rebuild kits, and a speaker upgrade for my pimped-out Lynx).

For the time being, I'll keep the Vader's chips in my original console, so that for the first time in almost six years, I finally have a working heavy-sixer-in-a-light-sixer-Sears-shell 2600 again.

Now all I need to do is find another set of six chrome-capped switches. :ponder: