Defender - 2 Cycle Rug Pattern?

machfelon

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Got a Defender yesterday via trade.

On power up it makes the musical notes then goes to a Rug Pattern.
It cycles between 2 different patterns. The first one and then it scrolls to the second one.
Rinse and repeat.

Which chip on the board could be bad?

2) I have 3 Sinistar boards that look identical to the main board in my Defender. Are any of these chips interchangeable? And if so are these chips soldered on or just push on chips? Couldnt tell.

Thanks
 
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Also note got the ram error right before this. Game worked good played it for a few mins then bam reset and ram error. No specific ram # just ram error
 
Did you check the voltages on the power supply? What are the led's telling you? Try re-seating the ram chips.

1) This game does not have a modern switcher has original power supply.
2) All the LEDS are burnt out and do not illuminate at all. Only 3 LEDS lit on original PSU.
3) I tried resetting all chips but they are pushed in hard and cannot move anymore.
4) Is Sinistar ROM 7 the same chip as DEFENDER ROM 7? Heard ROM 7 is first one to go.
I went so far as to plug in a Sinistar ROM Board into the cabinet to see if I could determine where the problem was but all it did was make black screen (oops) ;)

If I could replace some Defender ROMS with SINISTAR ROMS it would save me some trouble since I have 3 roms boards sitting here. Also is there a trick to get these ROMS out? They are extremely hard to remove.
 
The initial data I would gather would include the output voltages from your power supply (measured from the various numbered test points on the power supply board, and also on the 15-pin connector itself), and the voltages at each corner of a RAM chip of your choice (these should be 5V, -5V, 12V, GND). If you don't already have it, you can get schematics, layouts, and Theory of Operation docs at the Defender section of arcade-museum.com.

Lots of these rug test failures are caused by voltage drops on these rails somewhere along the way - e.g. bad cabling, broken or corroded edge connector pins, etc. I had this happen recently (5V dropped to 3.7V), and the problem was a cold solder joint on that 15-pin connector (which meant different results everytime I touched or removed it, since the resistance would vary - fun stuff!)

LeChuck
 
Sinistar and Defender boards are not at all interchangeable. The MPU boards (large rectangular boards) are significantly different as are the ROM boards.

Defender MPU boards are interchangeable with other Defender MPU boards. Period.

Later MPU boards are slightly more interchangeable.
Revision 0 (or '-') run Stargate only without hardware mods. This has small upside down daughterboard on row 6.
Revision B, C & D run Stargate + Robotron, Joust, Sinistar and Splat!
Bubbles MPU boards (different part number) run Bubbles. This has 2 CMOS RAM chips on board.

ken
 
1) This game does not have a modern switcher has original power supply.
2) All the LEDS are burnt out and do not illuminate at all. Only 3 LEDS lit on original PSU.
3) I tried resetting all chips but they are pushed in hard and cannot move anymore.
4) Is Sinistar ROM 7 the same chip as DEFENDER ROM 7? Heard ROM 7 is first one to go.
I went so far as to plug in a Sinistar ROM Board into the cabinet to see if I could determine where the problem was but all it did was make black screen (oops) ;)

If I could replace some Defender ROMS with SINISTAR ROMS it would save me some trouble since I have 3 roms boards sitting here. Also is there a trick to get these ROMS out? They are extremely hard to remove.

With the original power supply its even more important to check the voltages. Re-seating implies to remove and re-insert. Original power supply only has 3 led's. Even if all are lit, you may still not be getting the correct voltages.
 
machfelon - Any updates on this issue? If you got it resolved, what was the root cause?

LeChuck
 
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