Galaxian help

don1400

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Hello,
Got a Galaxian board that needs some repair and was wondering if some of the experts here might have an idea what's going on. Attached is a vid of the board running.

Some prior repair work has been done to the board, new sockets on main board, 245's replaced, socketed, as are all 6 Ram chips, Z80 good, daughter board verified working properly. ROMS have correct checksums. I did a complete point to point continuity check on the data and address buss's, all ok. Reset line pulses from high to low all the time, when I push reset switch it goes low as long as I hold switch in. It's a bit didfficult to see but when the dots are on the screen you can see star field, they run up, also notice some letters numbers are upside down.
Anyone have any thoughts on where the problem could be, I found a few repair posts on places like Mike's arcade and others but none had any of the symptoms my board has.
Thanks for any help in advance.
Rich
 
I am in the process of restoring a galaxian, I did not know there was a daughter board for this, thought it was a single board just like PAC man. Do you have pictures of the boards? Want to make sure I have everything I need. Hope someone can help out with the repair.
 
I am in the process of restoring a galaxian, I did not know there was a daughter board for this, thought it was a single board just like PAC man. Do you have pictures of the boards? Want to make sure I have everything I need. Hope someone can help out with the repair.

I could be wrong on this but I think Bally at some point eliminated the daughter board and redesigned the PCB with 5 individual sockets in row 7. Maybe what I saw at the time was a bootleg PCB. If your PCB has just 2 24 pin sockets in row 7 you are missing the daughter board. There's an excellent pix of PCB with daughter board on ebay, here: http://cgi.ebay.com/ws/eBayISAPI.dl...988854&ssPageName=STRK:MEWAX:IT#ht_3892wt_881
Hope this helps you out.
Anyone venture a guess on the problem with my board?
Thanks,
Rich
 
I got you, I was thinking of something like Ms Pac, where the board is connected with a cable. The one I bought does have that daughter card. I bought one of the high score save kits which will eliminate this daughter board when I hook it up.
 
Look up watchdog in the TS guide.. If the reset line is pulsing, its watchdogging, and either the z80 isnt runnning, or something in your data/addressing structure is frozen.

Good Luck!

Andrew
 
Have you tried the Galaxian Troubleshooting guides?

Arcade Archive has them, http://arcarc.xmission.com/

Been through the guides and changed out 5 chips, still no change. Reset line continues to pulse hi to lo which according to what I've found online and another members info indicates a likely problem with CPU or data/address lines. Z80 is good. Yesterday I took the logic probe and schematic and went point to point on the address and data lines. I found a signal at all pins, none were floating, however I'm not fully versed as to weather the signals were correct or not. I need to pickup one more chip and replace it, if it still doesn't work I'll find another board.
Thanks for the help.
Rich
 
Been through the guides and changed out 5 chips, still no change. Reset line continues to pulse hi to lo which according to what I've found online and another members info indicates a likely problem with CPU or data/address lines. Z80 is good. Yesterday I took the logic probe and schematic and went point to point on the address and data lines. I found a signal at all pins, none were floating, however I'm not fully versed as to weather the signals were correct or not. I need to pickup one more chip and replace it, if it still doesn't work I'll find another board.
Thanks for the help.
Rich

I had a galaxian board recently where the 'WAIT' line to the processor was stuck low, therefore the processor would never start, just a screen full of random things, was a torn track on the board. cannot see your video so no idea if thats a help or not. Where in the world are you?

cheers
Andrew
 
Been through the guides and changed out 5 chips, still no change. Reset line continues to pulse hi to lo which according to what I've found online and another members info indicates a likely problem with CPU or data/address lines. Z80 is good. Yesterday I took the logic probe and schematic and went point to point on the address and data lines. I found a signal at all pins, none were floating, however I'm not fully versed as to weather the signals were correct or not. I need to pickup one more chip and replace it, if it still doesn't work I'll find another board.
Thanks for the help.
Rich

just wondering if you ever got this board up and running.
 
I have seen something in other posts and some web pages I downloaded about the upside down lettering and numbers. I look into it more and get back to you with where and what to look for.
I had a problem with a board and after cleaning the pins on chips and checking everything I was about to quit for the night. I decided to play with the dip switches and that was it.
 
I am having problems with my galaxian roms. I have some blank roms and several files but I think I may be doing something wrong. The roms I have checked from my board don't appear in the romident at all.

The rom files I downloaded have an extra rom file that I do not seem to have. I also do not understand what files go where when I do program them. This is a midway galaxian board set.

I have also read somewhere that there is supposed to be voltage (+5) put to pins e and 5. Is there any truth to this? Schematics show a nc and coin counter on the pins.

I changed the zilog z80 cpu chip (working or not) and it seems to be working fine. I almost sure that my problem is the program (roms).

here is a pic of the board.
 

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That is not an original piggyback rom board and was probably for a game variation and would be interesting to see what it was. It may still be ok but in order to rule out the roms, solder a socket in the empty location and try burning a new complete rom set including the two graphics roms on the main board.

If you intend to repair these, a spare working piggyback ROM board is a great troubleshooting aid to immediately eliminate if the rom board was your issue.

Bill
 
That is not an original piggyback rom board and was probably for a game variation and would be interesting to see what it was. It may still be ok but in order to rule out the roms, solder a socket in the empty location and try burning a new complete rom set including the two graphics roms on the main board.

If you intend to repair these, a spare working piggyback ROM board is a great troubleshooting aid to immediately eliminate if the rom board was your issue.

Bill

The problem I am having is where what rom goes where. I know the 1k and 1l but the others on mame are u, v, w, y. Where does u,v,w,y go? I don't really want to just put them in any spot.

Also I noticed on the schematics that the eproms are 2716 and on this board they are 2732. When I read them, I read them as the 2732. Would this make a diffrence?
 
The problem I am having is where what rom goes where. I know the 1k and 1l but the others on mame are u, v, w, y. Where does u,v,w,y go? I don't really want to just put them in any spot.

Also I noticed on the schematics that the eproms are 2716 and on this board they are 2732. When I read them, I read them as the 2732. Would this make a diffrence?

Looking at the ROM board from the Main PCB connector end, notches toward 1K & 1L, the ROMS are as follows U,V,W,Y,Z. Your main board is the same as mine, revision C and used 2716 ROMS. The 2 different ROM types are not totally pin compatible. As mrbill said get an original ROM board and go from there, however if you are a gambling type burn the files onto 2716 chips and see what happens, GND and +5v pins are the same. What is the number of the small 16 pin chip on your board, schematic shows it as a DM74LS42N. I got rid of my Galaxian in a trade but I think I may have the ROM board somewhere, I did the upgrade to include Super Galaxian and didn't needed it anymore, you can have it for shipping if you are interested.
Rich
 
Looking at the ROM board from the Main PCB connector end, notches toward 1K & 1L, the ROMS are as follows U,V,W,Y,Z. Your main board is the same as mine, revision C and used 2716 ROMS. The 2 different ROM types are not totally pin compatible. As mrbill said get an original ROM board and go from there, however if you are a gambling type burn the files onto 2716 chips and see what happens, GND and +5v pins are the same. What is the number of the small 16 pin chip on your board, schematic shows it as a DM74LS42N. I got rid of my Galaxian in a trade but I think I may have the ROM board somewhere, I did the upgrade to include Super Galaxian and didn't needed it anymore, you can have it for shipping if you are interested.
Rich

Yes, I'll take it!

The small chip in the center of the board is a 74LS42PC.

I don't have any 2716 chips and most of my 2732 I sent to chanelmaniac for testing.
 
The small rom board has some kind of soldering pad for swithing some pins around I think. This is not a good pic but here it is.

Also there is some kind of mod. done to this board. I had to replace the sockets going to the rom board and was going to do the same for 1k and 1l untill I seen this.
 

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Would that mod on the rom chips be for the 2732 chips instead of the 2716 chip?

Also I think (can't remember) that jumper tied pins 25 on 1K and 1L to pin 1 on 3j and 3k. I am not sure of the positions but the chips were the same and possibly 74ls157.
 
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Looking at the ROM board from the Main PCB connector end, notches toward 1K & 1L, the ROMS are as follows U,V,W,Y,Z. Your main board is the same as mine, revision C and used 2716 ROMS. The 2 different ROM types are not totally pin compatible. As mrbill said get an original ROM board and go from there, however if you are a gambling type burn the files onto 2716 chips and see what happens, GND and +5v pins are the same. What is the number of the small 16 pin chip on your board, schematic shows it as a DM74LS42N. I got rid of my Galaxian in a trade but I think I may have the ROM board somewhere, I did the upgrade to include Super Galaxian and didn't needed it anymore, you can have it for shipping if you are interested.
Rich

Is that u,v,w,y,z going from top to bottom or bottom to top?
 
I'd recommend doing away with the ROM board and doing the mod which eliminates it completely, those daughterboards are a constant source of problems.
 
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