I would say that before desoldering anything, I'd strongly recommend testing the output voltages on the power supply. The fact that it shows a picture after the "power supply warms up" suggests a bad solder joint or defective power regulator in the power supply. I'm not qualified to fix a power supply like this, but I've seen it often enough that I know the symptoms (and once upon a time I had the ColecoVision technician repair manual, so somewhere in the back of my head I have a list of diagnostics and the corresponding symptoms and maybe even fixes -- boy I wish I scanned it at the time).
My brother Neil talked with the Telegames rep during the introduction of the Dina and they had a vision to eventually make some expansions for it, but I suppose they never did.
Thanks for the tip! I hadn't thought of that, I just figured the problem was the video processor...it's like the VDC needed to warm up. Would a faulty power regulator or solder joint explain garbled graphics? The garbled graphics tend to be the same patterns, eventually improving to a clear picture before going "back" to columns of dots on the game screen and game option screen.
That's a cool tidbit about the expansion! Never heard that before. It sheds some new light on this system.
Atari 5200: great system, but unsupported, mistimed, and, in retrospect, perhaps a misstep. Its hardware (read: controller) issues were on the verge of being ironed out when the crash hit, and in its two or three short years, the 5200 accumulated a library of high-quality game titles. The 5200 to me always seemed like a victim of circumstances.
Vectrex: released at the worst possible time. Not much else to be said there. Like the 5200, a victim of circumstances.
Honorable mention- 3DO: an interesting, innovative system with a lot of potential and a few really cool games. Most of its games are pretty garbage though (but to be fair, I guess you could say that about most systems, like the PS2 or Atari 2600). Certain marketing/pricing decisions didn't do it any favors.
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I wouldn't call the Odyssey 2 or Dreamcast failures exactly. They weren't top-dog systems, but they were on the map, at least. Which is more than can be said for things like Arcadia 2001 or Nuon.
Astrocade is another one I don't really feel is fair to call a failure. It wasn't a smashing success, to be sure, but the thing wouldn't go away; it was even kept on life support into the mid-'80s by a company formed by hardcore fans (iirc). That says something, I think.