TECH: Tempest PCB help...

[Scott]

Archived from groups: rec.games.video.arcade.collecting (More info?)

Been fixing up a Tempest for a customer, but this one has me a bit
stumped. Figured I would ask here as I know there are a lot of Tempest
experts around.

Game was dead originally, so I fixed the power supply. Entire thing
has been rebuilt on the ARII and the power supply block. We have
power.

Board doesn't boot most of the time. Usually just get it stuck on the
one and two player buttons lit and nothing on screen. When it does
boot, it plays blind. The spot killer is lit on the board each time.
Sometimes it'll give a dot made up of small and seperate red, blue, and
green lines on the screen...sometimes it won't.

Monitor has the brand new Arcadeshop boards installed. The PCB has to
be the prob.

Y output shows voltage. X output does not. DAC test point shows a
dead 0. Have reseated and cleaned all the ROMs...board doesn't behave
any differently.

Thoughts?

 

[Scott]

Archived from groups: rec.games.video.arcade.collecting (More info?)

Thanks, Matt.

Edge connectors are fine and already reseated the socketed chips. I'll
hit up the rest of that stuff and let ya know.

 

[Guest]

Archived from groups: rec.games.video.arcade.collecting (More info?)

> Y output shows voltage. X output does not. DAC test point shows a
> dead 0. Have reseated and cleaned all the ROMs...board doesn't behave
> any differently.
> Thoughts?

I had this once on a friend's Tempest and it turned out to be a dead
voltage regulator on the Tempest PCB.

Check that out!

D

 

[Guest]

Archived from groups: rec.games.video.arcade.collecting (More info?)

First, make sure the solder joints on the connectors between the two
motherboards are okay. They often become intermittent. Reflow them.

Second, see if there's any "heat rot" on the edge connectors. Measure the
+5.0 volt line on each board and see if it's in spec; a corroded connector
can make it lower than it should be.

Third, re-seat all of the socketed chips. This is a common failure mode.

Fouth, put the game in self-test and note the number and pitch of all the
beeps. That could indicate a bad 2114 RAM chip.