Dragon's Lair self-test

[smartbomb2084]

Does anyone know if a Dragon's Lair will perform the self test without the Laserdisc player being present or working?

Switching DIP switch A7 and waiting for the 'Beeps' as the manual suggests does not generate any video. 

THANKS

[MonMotha]

All of the video portions of the tests are stills off the Laserdisc, so obviously none of that will work.  I don't know if any other parts of the test will operate.  It may bail on the tests without any feedback from the LD player and not give you any beeps.

[smartbomb2084]

Thank you for the response.  I was afraid of that. 

According to the manual however, it does state that the self tests "reside in the Z80A game program EPROM".
So wouldn't that mean they are on the Main CPU board?

The game does 'beep' when you power it up and when it initializes the Laserdisc. The disc is moved under the laser but after about a minute it gives up, pulls back out and stops spinning.

The Player 1 and Player 2 displays all have dimly lit strobing 'FFFFFF'

The weird thing is the game does register credits and does show them properly on the Credits display but of course, the game does not start.

[MonMotha]

The *program* that runs the self test is indeed on the ROMs, however the game board for DL actually has no video output.  All video is generated by the LD player (the LD player is in fact hooked up directly through the monitor through an NTSC to RGB board, which essentially turns the arcade monitor into a TV).

The dim FFFFF is normal for DL.

I'm not surprised that you can coin it up.  My recollection is that it'll just sit there forever waiting for the LD player to respond when it tries to cue the intro scene.

[smartbomb2084]

Thank you AGAIN for the response.

Once again, I failed to use the best tool in my toolbox ----My EYES---- and should have deduced that the CPU has no video output of its own just by looking at the wiring and NOTICING the only input, aside from +16V, to the NTSC board is a 75 ohm Coaxial cable coming FROM the player.  Sorry about that.

The conclusion thus far is that the main CPU board and power supply (which was checked) seem to be good since the game does coin up, Beep, tries to read the Laserdisc, and has normal FFFFF on the display.

So then the problem is likely the LD Player or the NTSC converter board.  We tried playing a regular Laserdisc wth the Player hooked to a TV and got the same result as in the game-- just a white screen with a grey 2 inch band at the bottom.

So can we hook an NTSC source like a DVD player to the NTSC board and have it display on the game monitor to test the converter board's condition?

[MonMotha]

So can we hook an NTSC source like a DVD player to the NTSC board and have it display on the game monitor to test the converter board's condition?

Sure can.  It's just standard NTSC composite video.

The LD players are by far the most common failures in these games.

[smartbomb2084]

Thanks.  We are gonna have to try it later in the week.

[smartbomb2084]

Tried hooking up a VHS VCR to the NTSC board but did not have the correct BNC type connector/adaptor. As before, jumper wires were tried with the same result--- no video.

I guess I am going to have to get the correct cable to be sure although the jumper wires worked on an old TV.