Asteroids center fold over in the X direction

[Arcadenut]

Here is a video of it:

http://www.youtube.com/watch?v=soZysUKiXNg

After looking at the schematics, I decided to swap D11 and B11 to see if the symptoms changed from a Horizontal problem to a Vertical problem.

After carefully removing the existing chips, I socketed them and swapped them around. The problem moved. So that means the AD561J is bad.

Is there a cheap alternative to the AD561J?

 

[Solder]

You could use an AM6012 (DAC312) BUT it's a larger chip in a slightly different location. You would also need to populate the area with new capacitors and resistors (and a socket for the chip) as per the schematics in order for the board to support it (which partly depends on your board revision). Grab the schematics and take a look:

http://arcarc.xmission.com/PDF_Arcade_Atari_Kee/Asteroids/

 

[Talon2000]

Some boards have the alternate locations to do what Solder said. Of course the easiest way is to bite the bullet and get a new AD561. If there is a cheaper more plentiful chip I haven't seen it yet.

 

[ELutz]

I've gotten them from here...
http://www.arcadechips.com/index.php?cPath=27_24

Much better than Jameco's price!
http://www.jameco.com/webapp/wcs/st...amecoall&ddkey=http:StoreCatalogDrillDownView

Edward

 

[channelmanic]

That's one chip I haven't found surplus yet.

 

[Arcadenut]

Ordered some from Arcade Chips. I might order some of the alternative to have on hand for a rainy day

 

[Arcadenut]

I've gotten them from here...
http://www.arcadechips.com/index.php?cPath=27_24

Much better than Jameco's price!
http://www.jameco.com/webapp/wcs/st...amecoall&ddkey=http:StoreCatalogDrillDownView

Edward

Yeah, the cheapest I've seen (other then Arcade Chips), was something like $30. At that price I could live with a minor defect in the video


Thanks everyone for your help.

 

[Solder]

I've also come across boards that use a part that looks like an AD561J, but printed on it is:

AD40715


Incidentally, should anyone wish to use an AM3012 (DAC312) instead, here's the details on the resistors and caps that are required:


Asteroids Rev 05 board:

AM3012/DAC312 at D12:

R148 = 10K +/- 5% 1/4W Resistor
R149 = 10K +/- 5% 1/4W Resistor
R150 = 4.7K +/- 5% 1/4W Resistor
R151 = 10K +/- 5% 1/4W Resistor
R152 = 8.2K +/- 5% 1/4W Resistor
C124 = .1uf Ceramic Disc 25v Radial Lead Capacitor
C125 = .1uf Ceramic Disc 25v Radial Lead Capacitor
C126 = .1uf Ceramic Disc 25v Radial Lead Capacitor
C127 = .1uf Ceramic Disc 25v Radial Lead Capacitor
C128 = .1uf Ceramic Disc 25v Radial Lead Capacitor



AM3012/DAC312 at B12:

R153 = 10K +/- 5% 1/4W Resistor
R154 = 10K +/- 5% 1/4W Resistor
R155 = 4.7K +/- 5% 1/4W Resistor
R156 = 10K +/- 5% 1/4W Resistor
R157 = 8.2K +/- 5% 1/4W Resistor
R158 = 2.2K +/- 5% 1/4W Resistor
C129 = .1uf Ceramic Disc 25v Radial Lead Capacitor
C130 = .1uf Ceramic Disc 25v Radial Lead Capacitor
C131 = .1uf Ceramic Disc 25v Radial Lead Capacitor
C132 = .1uf Ceramic Disc 25v Radial Lead Capacitor
C133 = .1uf Ceramic Disc 25v Radial Lead Capacitor


Early revisions of Asteroids boards (for example, Rev 2) that have no
location markings for these extra components yet that do have the ready-made yet
solder filled holes:

Same as for Rev 05, BUT the location R158 is missing from the board - to fit R158,
attach one lead to the left hole of R157 and the other lead to the metal ground that
is so prevalent in this area


Asteroids Deluxe Rev 01 board:

AM3012/DAC312 at C/D11:

R81 = 10K +/- 5% 1/4W Resistor
R82 = 10K +/- 5% 1/4W Resistor
R89 = 4.7K +/- 5% 1/4W Resistor
R90 = 10K +/- 5% 1/4W Resistor
R119 = 8.2K +/- 5% 1/4W Resistor
C52 = .1uf Ceramic Disc 25v Radial Lead Capacitor
C53 = .1uf Ceramic Disc 25v Radial Lead Capacitor
C80 = .1uf Ceramic Disc 25v Radial Lead Capacitor
C90 = .1uf Ceramic Disc 25v Radial Lead Capacitor
C91 = .1uf Ceramic Disc 25v Radial Lead Capacitor


AM3012/DAC312 at A/B11:

R83 = 10K +/- 5% 1/4W Resistor
R84 = 10K +/- 5% 1/4W Resistor
R91 = 4.7K +/- 5% 1/4W Resistor
R92 = 10K +/- 5% 1/4W Resistor
R124 = 8.2K +/- 5% 1/4W Resistor
R125 = 2.2K +/- 5% 1/4W Resistor
C54 = .1uf Ceramic Disc 25v Radial Lead Capacitor
C56 = .1uf Ceramic Disc 25v Radial Lead Capacitor
C82 = .1uf Ceramic Disc 25V Radial Lead Capacitor
C90 = .1uf Ceramic Disc 25v Radial Lead Capacitor
C97 = .1uf Ceramic Disc 25v Radial Lead Capacitor