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Maraakate

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About Maraakate

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    Space Invader
  • Birthday 04/06/1988

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  1. Now, there is two caps under that large heatsink. One must be a bi-polar cap, and the other is polarized. Maybe they could be wrong. But I don't know if they would cause this issue or if the OP replaced those caps. Most people don't bother to.
  2. Yeah but he said he was using for a week. Now, if that was for 5 seconds to see the intro tune every night when he got home then maybe. But, I've never wired up a cap backwards yet so I can't say for sure how long it would take. I still think it has something to do with the DAC pot being dirty or possible one of the chips in the DAC circuit itself causing it to go nuts. The only caps by that are are the poly caps and a few non-polars. I don't recall if the non-polars are mylar, but I think they are and there probably is no reason to suspect they are bad. But any bad or questionable solder joint in that general area could be cause for concern with intermittent vectors with no regards for proper intersecting > .
  3. I would imagine if a cap was reversed wouldn't it have popped by now?
  4. Okay. Thanks for this. I figured it probably should be some lighter type of silicone grease. Lithium grease could possibly work, but it's very temperature dependent.
  5. Maraakate

    Vectrex issue

    I got a vectrex recently that wouldn't read carts. I ended up spraying the contact cleaner directly into the socket and used a title I didn't care for and was of little value and repeatedly removed and reseated the cart then let the contents evaporate. I haven't had a problem reading games since.
  6. This is a somewhat large bump, but what kind of grease did you reapply? I don't think white lithium grease is appropriate. But maybe the Dow Molykote stuff used in VCRs and other small plastic gears may be OK? Or is it simply dielectric grease?
  7. Do the same deal for the integrator potentiometers too if you can. They're also on the logic board. Incorrect adjustments of the High Voltage pots on the power board only help to minimize the blooming effect from bright and large objects on the screen; so we can probably rule that out.
  8. But, back to the DAC pot.. Check the solder joints of the pot, clean it with some contact cleaner, and move it left to right like ten or twenty times. Check the solder joints of the metal film resistors by this pot. I would just reflow solder and the top and bottom of the vias of the metal film resistors and the pot and see if that works. When I replaced the metal film resistors in a previous unit I noticed the same kind of craziness. Directly pressing my finger on the metal shell of the pot would cause the vectors to go haywire like what you showed.
  9. Other thoughts could be that the AtariVox itself had some soldering issue and hurt the sound chip (which also is linked to the controllers). Or that your DB- connector for Player 2 had some sort of bad connection and took out that chip. However, I don't know if the AY sound chip is responsible for any part of the drawing scheme.
  10. I mistook it for IC401 But he had this say to in another thread: "I was finally able to fix the Vectrex today. Of all things, it was a short between one of the voltage regulators and the big heat sink. I added an extra piece of plastic to separate them (thickening the stock piece) and it fired right up." I was thinking maybe because the heatsink wasn't reattached properly or the grease has failed and possibly has damage from being cooked.
  11. This might be more than you are willing to do, but since you have no scope... can you remove the logic board from a working system and swap them to see if it is a problem with the logic board or possibly a problem with IC401?
  12. Very possible. Or it could be a bad solder joint around that area too. Spray the contact cleaner somewhat judiciously on the socket then remove and reseat the IC (find one with the same pin count or one you can break pins off to make it the same) multiple times. Remove it, then let it evaporate out. Be careful inspecting the solder joints on this IC. I do remember that there are two or three lines that are bridged. This is on purpose. The first time I saw it I mistakenly thought that I dropped a solder blob and it found its way to that spot when doing a recap.
  13. I've seen this happen if you put your finger near the DAC 0 adjustment potentiometer. Maybe this pot needs a good cleaning? If the polystyrene caps are all out of whack too they can cause vectors to run all over the place... But, look at this old website near the bottom: http://web.archive.org/web/20041128210425/http://perso.club-internet.fr/sap1/vec/vec.htm. It looks as if some defective ICs caused similar situations. So you may need a scope to check the waveforms of some ICs to verify they are proper. It may be possible that your quick fix for IC401 may have caused it to work harder than it needed to and cooked it.
  14. If the 6522 IO chip is bad this will not allow it to start, having a condition you describe (white dot with hum from speaker). Since you said it was lined up cockeyed it may have shorted the chip and destroyed. I did find a replacement IC for this that I have tested and it does work fine for most games. The intro screen to Thrust gets a little wonky, but if you need it now, cheap, and want to verify the IC is W65C22N6TPG-14. This chip can be found online rather cheaply. Let us know if it works for you. I haven't tested it to hell and back on many games, but the games booted OK and looked OK from a brief playsession.
  15. I've also mirrored everything (and a few other vectrex related goodies) at http://dk.toastednet.org/Vectrex/
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