Odd Asteroids Problem

[tb lilley]

Asteroids fail to appear. They don't display in demo mode. Neither do they appear when playing the game in 1 Player mode (not just that they fail to get drawn, they're simply not there, as the game sill plays, have full control of ship, can fire but there's nothing to hit, saucers still turn up though and can be shot).

Here's the twist. Start a 2 Player game and it plays fine for Player 2. All Asteroids present and correct. Player 1 though they are still absent ...

Not heard of anything similar before. I'm short of test equipment (multi meter is about it) but any clues what might be causing the problem, and where to look?

 

[Equites]

James, run the Self Test mode and see if the cross hatch looks good. Any beeps?

 

[tb lilley]

Hi Nad. Ran self test. Hmmmm. Not looking good. Nothing displays on the monitor. At all. No beeps, just a single very low tone trumps out of the speaker ... Ram failure at D2? If so, why nothing displayed during self test? Still a bit bizarre that game plays fine as Player 2 .....

 

[Equites]

Hi Nad. Ran self test. Hmmmm. Not looking good. Nothing displays on the monitor. At all. No beeps, just a single very low tone trumps out of the speaker ... Ram failure at D2? If so, why nothing displayed during self test? Still a bit bizarre that game plays fine as Player 2 .....

Are your RAMs socketed? If not, whats your desoldering like?

I have to admit that playing ok on PL2 is a bit odd, not sure I understand that.

This is Asteroids not Deluxe right??

Equites2012-09-14 21:17:45

 

[tb lilley]

I'm a desoldering wizard Nad old son. Takes me about an hour mind you, working with a hot knife and the gas hob in the kitchen ..... (kidding).

Anyway, it's a place to start. Might even be socketed. I'll have to take a look see.

Yes, board is Asteroids, but runs in a DLX cab.

 

[Equites]

I'm a desoldering wizard Nad old son. Takes me about an hour mind you, working with a hot knife and the gas hob in the kitchen ..... (kidding).

Anyway, it's a place to start. Might even be socketed. I'll have to take a look see.

Yes, board is Asteroids, but runs in a DLX cab.

Okay, so we can rule out Mr Pokey then. Let me know if you need any 2114 RAM to play with, these tend to fare well with piggybacking too if the RAM on your PCB is not socketed.

 

[guddler]

I guess it _COULD_ be program RAM as P2 variables will be stored in different memory locations to P1, but not very far different so I'm sceptical!

Very odd one indeed, never heard of it!!

The other thing to try is the diag step - that may give some clues but I'm too tired right now to give instructions. Memory socketing is as good a place as any for the moment. Possibly even vector RAM. The more I think about it, the more I suppose it could be memory stack or something like that. The diag step tests fully exercise the subroutine stack so will be good to do.

Am I even making sense at this time in the morning??