big blue "fu" - how can it cause so many problems?

[xxstatic]

I wouldn't get too excited on the "big blue" being the "fix".

but ymmv........

 

[ENDOFLINE]

everyone talks about bob's big blues for sale....

any other place to buy these on the internets??

need to pick up a few for my atari machines.

 

[pacman71]

Big blue fixed 3 of mine. to be honest I also replaced the big blue and bridge rectifier in 1 of the 3. So it could have been either. I just didn't want to screw around figuring it out.

For what it costs and the ease of installation. It's not a bad place to start when strange things are afoot.

 

[OregonPacman]

The Dig Dug I used to own had a bad Big Blue at one time. One day when I turned it on, it had scrambled garbage on the screen. The ARII would only put out 4.3V or so on the 5V line. The input to it was not high enough. Replacing the Big Blue took care of it. All kinds of wierd problems can be caused by low power supply voltages. As you may know, DC voltage is rectified from AC. Before being passed through a regulator such as the ARII, there are ripples in the DC voltage that correspond to the frequency of the original AC line voltage. The Big Blue cap helps to (but not entirely) smooth out the ripples before the voltage can be regulated. As the cap dries out, it loses its ability to do this. The ripples in the voltage pass through the cap and into the ARII. If they make it into the final +5V line, they can cause all kinds of wierd problems. This is how problems can persist even when the voltage is correct.

 

[chris25810]

It's actually quite rare that these caps go bad to the point of causing real issues. Just like any cap, they are old and it's not a bad idea to throw in a fresh one but if you are one of the people that get talked into a replacement for a cure to your problems, you're most likely gonna be disappointed. The same thing can be said for filter cap replacement on monitor chassis, i've worked on thousands of these things and honestly i can think of only a few that needed replacement.

 

[channelmanic]

These systems run off of DC voltage. The output of the bridge rectifier is a bunch of rectified sine waves - all on the positive site. Big Blue helps smooth out and average that pulsating DC into something smooth than you can actually regulate down to a clean +5, +12, and the other voltage levels you need for your game.

When it starts to go bad, more and more voltage of those pulses make it through as ripple. The smooth voltage looks ugly and it's harder to regulate. This causes all kinds of issues in your game.

Just like old caps in switchers need replacing, replace Big Blue to keep your game running at its best.

 

[DogP]

Honestly... in ALL the games I've EVER owned... I've never had a bad big blue. I bought one from Bob Roberts many years ago trying to troubleshoot a Roadblasters problem, swapped it in, it didn't make a difference, and when I ended up finding the real problem, I swapped it back and kept the new big blue around for the next time I needed one. It's been 8-9 years now and I've still got that cap around waiting for the day that I'll have to use it more than to just rule out the big blue from being the problem.

DogP

 

[vintagegamer]

Well, as many have said, even though it may have made my Tempest run a little cleaner, it hasn't resolved any of my current issues with the game (except maybe some of the monitor graphics folding).

It's OK though, I was planning to put a new one in the game anyway regardless. But you can bet your butt I'll be keeping the old one too!