I purchased an astrocade that was not working and I'm trying to fix it. I've found internally that once AC power is plugged in, the voltages get dragged *way* down (the 7.5VAC gets dragged down under 3, and the 23 or so VAC gets dragged down under 10VAC). I think that big smoothing caps in the supply are toasted and was going to replace them. So I started looking over the motherboard, and started looking at it compared t the parts layout on the bally alley website.
All I can say is "Huh?"
First, I did realize that someone did the "Kludge board" modification in this system for video issues. OK, at least that explained why the video section under the shield was not what the board layout says. They also did the power modification where there is a jumper wire running from one of the bridge diodes to the + of the C6.
However, I see that there are a bunch of components missing.
Specifically it appears that the custom roms U1,3,4 are gone, and the associated caps are gone - C88,93,94.
Above the big smoothing caps C1 and C6, it seems that C61, 55, 56 are gone.
C58, 59, 60 in the vicinity of U14 towards the bottom of the board are gone.
Near the Q1 transistor (with the heat sink, just under where the modulator plugs in), it appears that there is a resistor where the jumper should be.
Now that gives me a *tad* of hope is that near U15, there exists C53 and C52 which are missing on my system. I did a search of motherboard pics, and I saw one person's where those were also missing.
I'm at a loss to describe these issues. I'm not WTF this is, if someone scavenged this, or it's normal, and if I should continue to fix it.
I also noticed that when I took the main cover off, I there were 2 screws that I could not remove until I removed the RF shield. The service manual seems to indicate that there are punched holes in the shield to do this, mine didn't have them.
Does anyone have any photos of working astrocades that they'd be willing to post? Or better yet, any knowledge of what's in my system?
Edited by TVisitor, Mon Apr 3, 2017 7:19 PM.