Galaga Blue Lines

Fudd

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Anybody know the cause of why i'm getting blue lines thru the game play...i had these before and after a cap kit ...would this be the video rams?
 

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Just swapped out the 74LS368 with a another one...no change..any other suggestions? I guess i'll swap out the (8) 2147's for (2) 2149's tomorrow and see what happens.
 
Also check the SIP resistor pack next to the 74LS298... If it's broken then the data lines from the motion RAM aren't tied high and you'll get that problem too.

RJ
 
Did you check the resistor pack next to the LS298?

If they are the flat blue/white or black/white kind they are known for cracking where the legs connect and causing problems.
 
Checked the resistor pack..they appear to be ok..they are not cracked.....replaced and reseated all socketed chips with no luck as well.
 
For some reason i can't get up close on the resistor pak..this is as best as i could get and you can't see squat....
 

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Replace it!

That type of resistor pack is the bane of Galaga and the cause of many problems. Replace ALL of the resistor packs that look like it.
 
Channel do you have the 1k ohm 5 pin resistors on your site? i need 3 of them to replace on the board...i have the 5 2.2k ohm ones already but i cant find the other ones.


errr i have 8 pin 2.2k resistors...those are showing 9 pins or is it just me?
 
Those are 9 pin ones...

8 resistors with a common connection to pin 1 which is connected to +5v. This ties those data lines high.

I'll check to see if I have any loose ones. I know I have a bunch pre-packaged with some Galaga "renew kits" I put together. It's basically a bag full of every 24 pin and larger socket plus all new resistor packs.

RJ
 
if you dont have the loose i may take the galaga "renew kit" depending on the price(my wife likes to nit pick my buying)..i dont see'em on the site either though.
 
Also check the ribbon cable connections from the CPU to the graphics board but it does look like a chip or sipp resistor problem.

Bill
 
Yea i think he is absolutely right with the sipp resistor being the culprit, we shall see. Just trying to track down the replacement parts now.
 
Problem Solved....RM5 sipp resistor replaced got rid off all the blue lines...i had another galaga video board i stole the resistor from. Channel, thanks for all you help, much appreciated and let me know if you have those galaga "renew kits" as i still want to replace all the other resistors...and feel free to add this to your repair logs with the pics if you'd like...thanks!
 
Welllll..ran the machine for 2 hours to verify the fix and now i have this....looks like i need to replaces all the resistors.
 

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You have a PM on the kit and an email with the instructions. They need to be proofed for spelling/grammar, and to insure accuracy on the steps involved. I think I have them pretty well nailed down though.

RJ
 
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Damn thats odd. I was just pulling part numbers last night to put together some of these galaga sip kits. Guess I wont bother since you already went through the trouble.
They used the cheapest bottom of the barrel parts on those damn galaga boards. I think they were designed to fail.
 
Welllll..ran the machine for 2 hours to verify the fix and now i have this....looks like i need to replaces all the resistors.

Do those lines come & go? do they move around the screen as the blue moves?

You might check that pesky 74LS368 chip again.

RJ
 
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