Black Widow DAC?

Todd31

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The game played blind so I installed Spaeths AVG and saw what you see in the pictures. Sometimes the graphics bounce between normal and this mess.

I think I am most likely looking at a DAC. What do you think? If you agree, what is the best way to narrow down which one has failed? If not then do you have any other suggestions? By the way, the monitor works perfect in Tempest.

Thanks,
Todd
 

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Is it possible to test the digital to analog converters with a meter by measuring input and output voltages or something like that? Does anyone know of any sources for these to be purchased? Have you ever seen a grown man naked?

Thanks,
Todd
 
Sorry, I can't answer your question, but there is a conversion circuit, using modern parts.

I have an asteroids made by taito, and the DACs are on a daughter board, whereas the original Atari Asteroids boards use a single IC

I have read of other guys here talking about this, but can't recall the thread.

If you need pics of a converter, I can take some / dig them out
 
Sorry, I can't answer your question, but there is a conversion circuit, using modern parts.

I have an asteroids made by taito, and the DACs are on a daughter board, whereas the original Atari Asteroids boards use a single IC

I have read of other guys here talking about this, but can't recall the thread.

If you need pics of a converter, I can take some / dig them out

Thanks for the reply. Your Amplifone page is awesome btw.
 
Interesting--my black widow board exhibits the same behavior every now and then. (maybe once every 20 times I turn it on.). Mine goes away on reboot. Right now I have Gravitar running, and it never does this, so I agree with it being board specific. I would guess an issue with the DAC circuit for the Y output. It is funny that some lines are flat but others are not. (example: the tops of the letters vs the bottoms of some letters). I am sure someone here has this figured out...
 
Yeah at this time I would just be replacing all of them to try and just shot gun it. I guess that's not a bad thing but I may have one or two dacs here that I can rob from other boards and be playing tonight, blindly replacing all will mean placing orders and waiting. It may not even be a dac though. You're right that someone would probably know what to go after.

Thanks,
Todd
 
I think I am most likely looking at a DAC. What do you think?

Might be. Might be some sort of Y counter, too.

Do you have a logic probe? Do you have pictures of what it looks like in test mode?
 
Might be. Might be some sort of Y counter, too.

Do you have a logic probe? Do you have pictures of what it looks like in test mode?

It looks fine in test mode but I don't have pics at the moment. Unfortunately I don't have a logic probe.
 
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