Asteroids Deluxe player two screen problems in cocktail cab

Jakewd

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Asteroids Deluxe player two screen problems in cocktail cab

Hi everybody,

I have an Asteroids Deluxe cocktail cab I've been working on restoring for the past 3 or so months. I've repaired the monitor and PCB, but I haven't been able to get the player 2 screen to work yet.

I purchased the Braze Multi-game kit, so I know it's not an outdated or incompatible game code. The player 2 screen seems to be displaying the proper image (video below), but it looks like its not sized correctly to the screen or something along the lines of that.

Any help or advice is highly appreciated.

Thanks,
Jake


Video Link:
https://drive.google.com/open?id=1tlwClvexmn9L6V1-nHE4U91ZoefxRZQ7
 
Bad 4016 analog switch at D12, which is part of the video inverting circuitry.

You say that this chip is apart of the inverting circuitry. Is there anything else in the circuit that could cause this problem? Or is it pretty much the only piece to it.
 
You say that this chip is apart of the inverting circuitry. Is there anything else in the circuit that could cause this problem? Or is it pretty much the only piece to it.

There is the video inversion circuitry (sheet2, side B) which has four 2N3906 transistors, uses +/-8.2V bias, and has misc resistors etc. These create the INV(), NINV() signals to the aforementioned analog switch. Something here could also be "bad". You'll need to visually inspect or probe the circuit to determine a possible issue.

Most often, however, the analog switches do fail.
 
Those transistors that VC is referring to just generate the voltages that activate the switches. The switches themselves are what the video signal passes through. So if the screen is flipping but the image is distorted, then it's the switches themselves. It's a fairly common issue on Asteroids and AD boards.
 
Okay, thank you for the responses. I'll see if I can probe it with my logic probe to see what exactly the problem is. Thanks for pointing me in the right direction.
 
Logic probe might not tolerate non-TTL levels ... i.e. +8.2V and -8.2V and +/-15V etc. Careful what signals you probe.
 
Yes, VC beat me to it. A logic probe will not help you, because the signals are analog at that point.

Just change the chip, provided you have PCB repair skills and capabilities. These boards are very easy to damage, especially in that area, so practice on a junk board if you haven't removed chips from boards before.
 
Don't forget to add a SOCKET. LOL :001_sbiggrin:

In the meantime, do a quick visual inspection ... might see something with the inversion components, or a bad trace etc.
 
Awesome, thanks for the help guys. I have done *some* board repair before, and while this doesn't seem to difficult, I will probably send it out to the person who repaired it before as long as they are able to test in the cocktail configuration. If not I feel confident enough that I could practice on a couple of junk midway pac boards I have laying around until I get a good feel for it.
 
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