Galaxian - No Stars

rchadd

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Hi have a Galaxian board that seems to be playing fine except there are no stars displayed.

I have done some research on various repair logs and found the following chips seem to be most responsible for the stars:

1A & 1B (74LS164 - 8bit shifter)
2A (74LS30 - 8bit nand)
2B (74LS366 - hex bus driver inverting)
1D (74LS107 - dual JK flip flop)
9N (74LS259 - 8bit addressable latch)

In particular it was suggested that should check pin 15 of 2B and also pin 9 or 9N which seems to enable the stars to appear.

My question is how should I check these pins?

Can I do it with a regular multimeter or do i need to get myself a logic probe?

I am wondering...could i build myself a simple logic probe with a led and resister? That would help verify presence of 0V or +5V right?

Would appreciate advice as I didn't want to first start playing with the board in case i end up causing even more issues! ;)

thanks in advance
 
my answer is buy another board set that works. galaxian boards cost next to nothing $25-$40. why kill yourself over this. Then you have your board set for parts
 
well it is definitely cheap if you live in the USA :)

i would like to try and repair if i can (if its a simple fix)

the reason why i want to repair is because it is Namco board and I am restoring a Namco Galaxian - most boards from USA would be Midway (and display that on the attract screen).

plus my board has been moded to have single EPROM which should be more reliable in long run...

i got myself a logic probe tested

pin 9 of 9N = High
pin15 of 2B = High

so not simple explain why no stars

I also tested the logic on all pins of 1A,1B,2A,2B and 9N but not sure how to interpret the results! Any advice on what should be expected results of a working board?


Incidently I also see that the Hit sound when you die is not playing - i have created new thread for that! :)
 
my answer is buy another board set that works. galaxian boards cost next to nothing $25-$40. why kill yourself over this. Then you have your board set for parts

well today i think you might be right. tried to do some troubleshooting as per galaxian manual and now see a new issue! at text appearing at bottom half of the attract screen is coloured red on bottom rows of pixels... maybe a memory chip issue?

think i'm going to give up on this board now...
 
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