Space Invaders Board Problems

[kb0jjn]

keep us updated to the progress of this as it is not fully working. I like it when they are fully functional and it makes me happy when I can help someone else fix their boards.

Bill

 

[Talon2000]

High pitched squeals are typically bad Tant caps.

 

[kb0jjn]

How is this one going?

 

[ForKChop]

Finally got the chance to sit down and replace the 4006 chip. That fixed the sound issues with the base explosion and the shooting sound. It's now 100% functional. Of course that just leaves me with deciding just how much of a restoration to do. I'll clean it up first and see what the major problems are.

 

[channelmanic]

Congrats!

Doesn't it feel great to bring a board back to life and fix those nagging little issues?

 

[kb0jjn]

Finally got the chance to sit down and replace the 4006 chip. That fixed the sound issues with the base explosion and the shooting sound. It's now 100% functional. Of course that just leaves me with deciding just how much of a restoration to do. I'll clean it up first and see what the major problems are.

This is why I enjoy this arcade stuff, I like it when I can help someone else fix their own stuff.

This is gravy for me.

 

[ForKChop]

That's for the help guys, I'm now waiting on a cap kit from Bob Roberts along with some new leg levelers. After tipping it over, well, it was hard to move because there were no leg levelers. Bottom couple inches has some delamination as well. Eh, I'll get it bright and happy then deal with the rest.

 

[ForKChop]

Cap kit installed, but the monitor is still too dim to play without watching the monitor itself. Turning brightness up goes to a white screen with stronger white lines (wrapping?), contrast works on the low end, it goes to an all black screen; but it's choppy on the way.

Is there something else that could be affecting the brightness, or is it likely to be the contrast pot?

 

[kb0jjn]

Cap kit installed, but the monitor is still too dim to play without watching the monitor itself. Turning brightness up goes to a white screen with stronger white lines (wrapping?), contrast works on the low end, it goes to an all black screen; but it's choppy on the way.

Is there something else that could be affecting the brightness, or is it likely to be the contrast pot?

I really don't think that is it. I was thinking something more like the fly-back but then I read this.

The part to pay attention to is at the bottom

Cleaning Up

http://girasoli.org/arcade/?p=295

 

[ForKChop]

I don't think it's grime, I've already cleaned both the mirror and monitor, and it's got a new white black light bulb in there. It's dim even looking directly at the monitor.

 

[kb0jjn]

When you did a cap. kit did you replace the fly-back circuit. The big bulky thing on the monitor board with the big red wire that will knock you on your @$$. You know the one going to the picture tube. This is what I was originally thinking.

 

[ForKChop]

No, just the cap kit itself. The monitor works, it's just dim. Could the flyback also cause dimness?

Doing some more reading, where is a good test point to check for the 73V coming off the regulator? What should the voltage be coming from the pcb?

 

[kb0jjn]

here is some more reading for you.

http://www.repairfaq.org/sam/crtfaq.htm#crtagd

Usually the regulators use one of the outside pins for input and the other for output. The center pin is usually ground.

I will look over the schematics later to confirm.

 

[kb0jjn]

I don't have the schematics for the monitor board so I can't really help you there. I did find some info for ya on the sticky about fly-back stuff.


http://forums.arcade-museum.com/showthread.php?t=134818&highlight=dim+monitor