Voltage Regulator Repair?

mikey.shake · February 24, 2015

About to “upgrade” one of my 4-switch systems to try and shake a little of the snow that seems to crop up. I get a flash when I throw the momentary switches (which I'll clean with Radio Shack contact cleaner while it's open). But I seem to get a little bit of a "twinkling stars" effect from time to time. It does seem to get a little worse once the console's warmed up. I'm also getting a little blurriness (noticeable to me as a "haloing" on the right side of the score digits in Megalomania).

My first thought was that it could be a “normal” amount of RF interference, so I bought a new shielded RF cable from Radio Shack (#42-2368) and a right-angle adapter to keep everything fitting easily inside the casing. But if that doesn’t work, I’m going to try replacing the 7805 voltage regulator and capacitor. I'm new at this, so before I do anything, I want to make sure I’m prepared. I’ve done some research, but can anyone clarify the following?

1) The only .1uF/100v capacitors I could find are mylar caps, rather than the “polyester radial” type. Will there be any tangible output difference between the two? Or is there any chance these aren’t optimal?

2) The only 7805-type regulator I could find was an NTE960 - a "5 volt positive voltage regulator” (fixed), right?

3) I’ve never worked with thermal paste before. This IS the right gunk from Radio Shack, right?

3) To do the same to a Light Sixer, I’d use a .22uF cap, correct? I know that the voltage shouldn’t make any difference, but the .22uF caps I found were 130v. Will this result in anything different than using a 100v, other than the size of the component on the board? If the 100v is slightly preferable, I’d rather just order one from somewhere.

Thanks in advance for your help. I'm loving playing these systems and just want to get them back to top-notch shape!

yllawwally · February 24, 2015

Mylar is a brand name of polyester cap, so that won't make a difference electrically. The shape different, but as long as you can make it fit, go ahead. NTE960 is a replacement for the 7805, so it will work just fine. The thermal paste from Radio Shack is what you're wanting. The .22uf would be correct. The voltage listed is simply the max voltage that it can handle, so as long as it's at least 10v, you should be fine. So technically the 130 would be slightly preferable. Although in use, it would indistinguishable.