hex65000 Posted September 16, 2003 Share Posted September 16, 2003 Okay, this is partially me bragging that I was able to fix one of my 2600 decks (Vader style w/ big stripe) I can't toot my horn too loud though, I had two that are pretty much DOA neither output anything intelligable even after extensive cart slot cleaning. A shame really, one is the heavy 6 switch and another one was the large all black 2600s. ANY-Way... on to the story... The console was coming up okay and the video looked good, but there just wasn't any color. I checked the BW/color switch and no joy. I left it on with Space invaders in and after 5 minutes all of the color was back. I then assumed a heat issue. I hate that Atari never bothered to properly heat sink thier regulators. After the machine was 'warmed up' I power it off, wait 2 seconds and turn it back on, the color is still munged up. Now I'm stumped and hit the forums... I spot the thread where the suggestion was made to try and tune one of the RF coils to see if that fixes the color. It looked like it worked, but after power cycling it was doing the same thing. So I suspect something goofy in the RF portion of the console, like a cap that's charging badly or an amp that has died. (which of course lacked the RF diagram) Then I spot this Variable resistor that says 'Color delay' Hmmmm... After cramming the testcart in with the top open I start poking what I think is the correct trimmer pot and my color does all sorts of exciting things. Such as work correctly! So I need to find a 500kOhm trimmer pot and replace the existing one. A doable project. Now, will I redo the power jack while I'm at it??? Tune in next time... For those who choose to experiment with this pot, be caeful not to turn it up too high, it looks like it overdrives something and blue things turn purple. Tweaking the RF coil is worth your time if your picture just doesn't look so good. and there is merit to the plastic allen wrench. Metal ones will notably change the magnetic field the coil makes. Try it without turning anthing and see what I mean, It's a fun experiment. But it is worthwhile just to tighten up your picture for a machine that is pushing 20 years of age in some cases. Hex. [ Last seen playing Bubsy and Demon Attack... ] Quote Link to comment Share on other sites More sharing options...
Csonicgo Posted September 16, 2003 Share Posted September 16, 2003 Yeah, I've caught myself playing with the color delay. I had to tweak it a few years ago. Quote Link to comment Share on other sites More sharing options...
hex65000 Posted September 23, 2003 Author Share Posted September 23, 2003 More of a followup with my adventures with the 2600... Some of this is just my notes as I attempt to restore these beasts to their proper glory. I wandered out to one of the local electronics stores and had no luck finding the correct trimmer pot (of course). So I decided to gamble with some one MOhm pots instead figuring I couldn't hurt anything by doing this. The result: It worked like a champ. The old pot had a fracture and had rust all over and underneath it. This explains some of the problems I was having with the unit. After this success, I decided to address the other concern I had: the voltage regulators. Being from a long line of packrats, I had access to a box of 5V regulators with a basic heatsink on it. The thing that sucked was that the sinks were attached to the regulator with a pop-rivet. That noise has got to go. I scrounge up some mounting hardware, replace the regulator, slide in the heat sink and some thermal paste and horse that guy on there tight. The operation is successful and the regulator has to be running cooler than previously, because that ground plate gets pretty warm now. Based on my measurements with a meter (and the power brick ratings): Vin = 10V ; Vout = 5V ; Imax = .5A Vreg = Vin - Vout ; Vreg = 10V - 5V ; Vreg = 5V MaxPower = Vreg * Imax ; MaxPower = 5V * 0.5A ; MaxPower = 2.5W Yeah, I am going to go through and redo all of my functional 2600s this way. Last up, I need to clean that 2600 with the formerly bad trimmer pot. I have given it a light scrubbing with denatured alcohol. What's nice is that it breaks the rosin flux down quite nicely. What has me nervous and may mean I do this a couple of times is that the flux gets everywhere if you don't get it off the board. I may have to eventually submerge it, but I don't want to go that route. It did clean up a lot of crud on the board though. More reports on this stuff as I go... Hex. [ Is seriously considering Mil-Spec pots for his paddle controllers... ] Quote Link to comment Share on other sites More sharing options...
vb_master Posted September 23, 2003 Share Posted September 23, 2003 Good job, and welcome to the forum! Quote Link to comment Share on other sites More sharing options...
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