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Mauro72

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About Mauro72

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    Space Invader
  1. Hi, I have this problem since blowup the first 74LS541N, the controller of port 1 and replaced with socket + new 74LS541N. No way to move up, the remain actions, fire, left, right, down are working. The Port 2 is Ok, all directions, fire, etc. Tested with 4 coleco original joyticks, all with this issue, no up movement. What pin control the up movement? May be a faulty track? Which? Any help? Thanks!
  2. I'm agree with NIAD. I think VRAMs chips is the problem. No VDP.
  3. Hi. Check the amps in the power supply. The voltage may be are ok, but its only a part. Another part is the "power" (amps) of the power supply. May be drop the amps and fail under load. Some 4116 bad too. Look my post here: http://atariage.com/forums/topic/262671-coleco-with-screen-out-of-sync-may-be/
  4. Hi, I have no image with memory mod. the 5v drop down to 2.5/2.7 in pin8 of each memory/slot. Is this value under load ok? ..mmmmmm Removing the 4516 ic the system "start" with black screen. And the chips are very hot after a few minutes on. The mod is about quit L2 and L3 and join +5v point. May be a part of the 5v is lossing on the way, may be a short circuit. But with 4116 are no problem. The system start normally. Any help?
  5. Hi, I'm searching schematics from differents boards. Example, in one board L27 is present, in other board not exist. Some inductors are with different value too. Another example, the repair manual from coleco put check R40, C62 in B/W image (sheet 4), but that resistor/capacitor no appears in my coleco board. How can i trace that? Is there some technical info/manuals with the differents revision? Thanks!
  6. Hi, I need to replace a 43 uH inductor from coleco board. But only i can get 47 uH inductor. Is ok? or may be can affect the board. How can i do for replace that inductor? Thanks!
  7. Yes, its ready. I have socketed VRAMs, VDP, Z80, 1889.
  8. Hi friends again, I have a PAL Coleco made in Hong Kong with black and white image. Tested with different wires, TVs, mod AV, 1889, VDP, always B/W. Reading the coleco repair manual, is totally different the capacitors/resistors numbers and layout in Hong Kong board version, no way to trace and verify. Any help? may be 7405?
  9. Fixed!!!! Mixed problems, faulty power supply and two bad vrams. Now working! Thanks!
  10. Hi friends, Is possible to mix those memory chips? I know, +5v in 4116 is leg n9 and in 4516/4164 is n8. So redirecting the +5v from leg n8 with a wire to pin9 and cutting leg 1 (-5v in 4116) and leg n8 +12v to +5v... may be work? In 4516/4164 leg n9 is A7, no needed for coleco... is correct? Thanks!
  11. Mmmmmmm... suspect discovery. A pnp transistor, 2N3906 near vdp. Anyone can confirm the value of EBC in board? Thanks!
  12. Hi again.. Trying with some cartridges, i noticed about sound. Is good, no problem. Here a small video with "Decathlon" game. https://youtu.be/JkmGIYVekJY
  13. Anyone know the specifications of that old inductor encircled? I want to change it. Thanks.
  14. Hi guys... It's a PAL version. nanochess, so i can connect a composite jack to pin36 (center) and the ground of VDP, external side of the jack (pin 1 may be, i need to search schematic of VDP). Ok, thanks!
  15. Hi, I have a coleco with out of sync i think with all games. Something like this: http://derbian.webs.com/c64diag/fault.htm?id=c19_1 I have 10,90v in pin 8 of RAMs (the 12v line). Its low? Any help? Thanks!
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