Post cap kit, something in my original Asteroids explodes...

Zoma

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Post cap kit, something in my original Asteroids explodes...

Hey all.

I recapped my Asteroids board in an attempt to fix a problem with the Y axis. I had done all but two caps (I had extra caps but none of the 470uf 25v caps) so it had been sitting idle for approx. 2 weeks. I had tested the thing but nothing had been affected. However, yesterday (after 2 weeks of not testing) I went in and replaced the two caps. On booting up something exploded and there was lots of smoke coming out of the back. The monitor still comes on fine and the game is okay too (the y axis problem still persists, I guess it was the monitor after all) but now there is a loud screeching sound coming from the speakers. I'm hoping this is just a coincidence and that my repairs didn't cause this problem, but it's really looking unlikely at this point. Where do I go from here, and does anyone know what I possibly could've done to cause this? Thanks.
 
a lot of time smoke means you reversed a cap. Meaning negative is on the positive side. Usually that will make the chassis not work depending on where it is located. Can you tell where the smoke came from?
 
a lot of time smoke means you reversed a cap. Meaning negative is on the positive side. Usually that will make the chassis not work depending on where it is located. Can you tell where the smoke came from?
I didn't touch the monitor at all; it must mean that the smoke came from the main board, from one of the two 470uf 25v caps (or possibly both) since those are the only two I replaced yesterday. But neither looked blown up, and I made sure the negatives were in the right place. I'll check them again today just to make sure I didn't miss anything. Will they look bloated or are they supposed to have some sort of corrosion coming out of them, or will it be less obvious?
 
Generally speaking the electrolytic caps on the game board do not control any of the analog output. They will smooth out the voltages for the regualtors, which feed the analog section.

The caps are for Incoming voltage smoothing, and audio sections.

You need to be looking into the analog section for Y problems, maybe the monitor. You should post a picture or video of the problem.
 
Alright all. Turns out I did put a cap on the main board in backwards. It was one of the 470uf caps like I had suspected. I'm going to replace this cap sometime tonight or tomorrow but is it likely that I've done damage to more than just the cap? Also, I'll get a video of the issue as well.
 
Hard to say, but in my experience you probably just ruined the cap. So replacing it and you should fine.

+1... I don't recall ever seeing any damage to anything else, except for physically broken items from the cap's explosion.
 
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