galaxian k4600 monitor

[frog]

I'm really new to this, but it looked like there are some really helpfull people on this site. Hope someone will help. I have a galaxian cocktail with what may be a monitor problem. I bought a new PCB on line for the galaxian to fix a (bad ram 3) problem and it worked fine for a few weeks. Turned it on one day, looked fine. Walked away and came back later and it looked like solid color bars across the screen.

Any advise would be appreciated.

[Kevin Mullins]

That's not a monitor problem..... Since the monitor powers up, has picture, and at least the words are legible.....then the monitor appears to be working just fine.

It seems to be a graphics/sprite display problem, possibly RAM issue.

Try re-seating all the socketed chips on the game pcb first.

[frog]

Thanks for the advise, unless I miss a chip, this didn't fix it. I'm really irritated if this is a PCB problem? I bought this board to fix the game in the first place.

[Level42]

Yep, but 26 year old boards are not always reliable anymore.

Looks like a graphic rom problem to me, but I'm not a real expert, I'm just checking lots of Galaxian info for the restauration of my upright.

Check out this page:
http://www.arcades.plus.com/galsingle.htm for some info on replacing the orignal ROMs with a Single rom (makes it more relialble). If you're not good in electronics repair, I think this guy can also do repairwork...but I'm not sure !!

Here's a page on his site with repair info:
http://www.arcades.plus.com/galaxianfix.htm

His e-mail adress is somewhere on the site...

Some more repair info:

http://www.guddler.co.uk/index.php?selected=7&content=19

http://www.jrtwine.com/jtwine/arcade/RLogs.htm

Just a question: what did you do with the original PCB ? I hope you didn't throw it away, these things deserve to be saved !

[frog]

I still have the original board. I thought at some point I would have it fixed. Guess that will be sooner than I thought. Looks like there a few people who will fix these, so I guess I will just have both boards fixed. I didn't want to believe the board I just bought was bad. I think the game was only played maybe a dozen times with the new board.
Thanks for the help.

[Kevin Mullins]

For whatever reason this popped into my head today.....

Try swapping your ROMS out from one board to the other. (one for one, one at a time)
See if the problem changes.

[Level42]

The Galaxian Trouble Shooting Manual Part I says:

"When character ROMs are removed the TV-screen will show horizontal bars."

Since there are still letters on your screen, I guess only one of the ROMs is not "seen" by the PCB.

Check out the lower PCB. When you hold the connectors to the top, the two roms are all the way on the bottom side of the PCB, right in the middle.

Look if they are firmly and completely inserted in the sockets. If not carefully press on them to get them back into place. If they don't look to be loose, remove them (lift each side just a tiny bit at a time, switching from side-to-side !), maybe clean the pins/sockets a bit and re-insert.
 
If this doesn't work you can take the ROM's from your first PCB (the one with the bad RAM) and insert these. Then at least you have one working PCB set.

The code on the chips should be (acc. to the service manual:)
M866L- D2316EC-647 and M866J - D2316EC-648