| Arcade Collecting > Restorations & repair |
| NPs Paperboy Restoration |
| << < (3/11) > >> |
| ChadTower:
Yeah, swap them both. Pretty much all caps with any real size to them. |
| Neverending Project:
We have a game! Well, almost... I hooked up an old switching power supply that I had to supply the +5V for the CPU, and the +12V for the fan. I hooked everything else up, and the game seems to play fine. The problem is the video is completely jumbled, and I'm not sure where to begin my troubleshooting. I have checked the voltages with the game running, and the 5V test points are at 5V and 5.5V, and the 10.3 test point is at 11.5V. I ran the self-tests and from what I can tell there are no RAM/ROM errors, since it proceeds right to the 6502 tests, and then to the tones. If there are RAM/ROM errors it will display an error page with the location of the bad ROM. Even though I can't read the screen, I can tell it progresses through all the tests. Here is a video with the game playing. What do you think I should check first? [youtube]http://www.youtube.com/watch?v=r2lmuhJMoJA[/youtube] |
| TheShanMan:
Nice! I wish I was as close with my Defender. Waiting on parts. Good luck figuring out that problem (I wouldn't know), but it must be exciting to get it to that point! |
| Neverending Project:
OK, I think I got the video uploaded correctly this time, and it should appear in the above post soon. So does anyone have any suggestions to what I should check first? |
| Neverending Project:
I have re-seated all the socketed ICs on both the CPU and the Video PCBs. I thought I found a chip that was incorrectly inserted, but my problem still remains. The 5V voltages look good on all the 5V test points I can find, and at pin 1 of a couple of random ICs that I tested. The only voltage I that doesn't seem right is the test point on the Audio/Regulator board - it should be 10.3V and is reading 11.5V. So I plan on replacing the Big Blue cap(s) and rebuilding the Audio/Regulator board. But my question is, does this really seem like a voltage problem? Running through the in-game test screens again, I ran into what must be a clue. On the attached picture, the picture should show the numbers 0-9, and then letters A-Z in yellow. Then they are repeated again in blue. According to the manual: --- Quote ---The Alphanumeric Test screen displays the condition of the alphanumeric ROM, alphanumeric color palettes, and associated circuitry. The displayed alphanumeric characters should be repeated twice with the first set yellow and the second set blue with red specks. If first set of characters is yellow and the second set is not blue, then there may be a problem with the color palette select circuits. --- End quote --- If you look closely, you will see the numbers 0-9, and then the character A, but then the rest is jumbled. It seems as this should tell me there is either something wrong with a RAM chip, or possiblly the ROM in the game? But then again, I have no idea what I am doing... so I ask you - could this be a voltage problem, or should I consider replacing the RAM chips? |
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