Asteroids - Fast blink

Can you try the other monitor or deflection board that you have? That will be the fastest way to narrow it down.

So I didn't move the whole display.. The one in my Battlezone actually has some dot burn in and it's a bit of a pain to pull the monitor so I wasn't sure it was the best test. But, I did move the deflection board as asked and got the same results. It took about ten minutes and then the dot showed up. Went away after game ends and comes back when starting a new game. The tube in this asteroids is pretty cherry is why I am sweating this so hard....


If you think it is a good idea to move the other tube over I will but wondering at this point what you guys think?
 
If it's not the Z amp/spot killer/contrast circuitry of the deflection board (which you've proven by substitution) then I'd guess it's something in the HV cage. Has it been recapped?
 
If it's not the Z amp/spot killer/contrast circuitry of the deflection board (which you've proven by substitution) then I'd guess it's something in the HV cage. Has it been recapped?

Yes, but I can swap the HV cage with my other one to test this. Also, I have noticed that the alien ships when them come into the game seem a little blury. But, maybe that is a red herring?
 
I agree with VectorCollector's idea about leaky transistors on the game board. Try replacing Q7 (2N3906), Q8, and Q9 (both 2N3904) next, as a start, as it's very likely something in the Z section.

They are easy, and fairly common (i.e., you might have some on some dead boards, from many other things). Also, look for cracked or broken resistors or caps in the area around them.
 
I agree with VectorCollector's idea about leaky transistors on the game board. Try replacing Q7 (2N3906), Q8, and Q9 (both 2N3904) next, as a start, as it's very likely something in the Z section.

They are easy, and fairly common (i.e., you might have some on some dead boards, from many other things). Also, look for cracked or broken resistors or caps in the area around them.

ZOUT, too, can always be scope'd out (similar to XOUT/YOUT method) in order to see if there is a DC offset or whatever anomaly on the signal.

As per the 19V2000 manual, ZOUT is more of a square wave with defined steps. Positive transitions only. (5Vpk)
 
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