Asteroids and AD having the same issue. Fustrated

starfighter2

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I thought I was getting confertable with these temermetal babies. But I feel Like I have No clue and have learned nothing. So I am looking to see if anyone can help me.

Both the Asteroids Deluxe and Asteroids games that I have seem to have the same issue. The game plays blind, no picture. The spot killer light is on and the neck tube is glowing. All fuses are good and both game boards have +5.15 to each board. There are no sounds on startup in test mode and there are no flashing lights. So It seems to pass the test mode. you can coin up and play blind. All buttons seem to work and can hear the sounds of the game as I play.


For the AD, I checked the Bridge rectifier and seemed to be bad in cuirct but good out of cuircut. I replaced anyway along with the bottom caps on the chasis. Also checked the D100 diode. Still nothing.

Looking on the foums I was that folks where checking to board both with AD and AC so not sure which way but the folowing are the voltages that I got even with a new battery with the test switch on from the coin door. Not even sure If Im checking correctly but this is the numbers:

Asteroids AC DC Asteroids Deluxe AC AD
-------------------------------------------------------------------------------------
z out 3.4 1.75 2.9 1.56
x out 0 8.91 28.9 13.45
y out 20.5 9.51 29.0 13.46


so know I have no idea what to do. if its the board, the monitors, I am even second quessing if I'm using my meter corrctly. So I walked away from it for today and thought I would get some ideas from you folks. I have seen others get fustrated and seems to be par for this hobby. But it seems very parculur that both where working and on week the AD went and a couple weekes later the AD went. Both are connected to surge potectors. Asl I only have a meter no scope to test with.

Thanks to all you can help be get these old girls back up and running.
 
What make and model monitor do you have in each of them?

Have you tested the power brick and the power supply for proper voltages?

The "X, Y, Z" voltages that you have provided mean absolutely nothing.
 
Sorry, Tried to put everything down and forgot the monitors.

The asteroids deluxe is a g05-802 version 5 board, the asteroids is a g05-801 but not sure of the version.
 
The "X, Y, Z" voltages that you have provided mean absolutely nothing.

Just because they mean nothing to you doesn't make them meaningless :)

In cases where someone lacks all of...
-known-good vector PCB
-known-good vector monitor
-oscilloscope capable of X/Y mode

...then looking at the AC content (in particular) of the X & Y output signals is helpful to determine if the problem lies in the game PCB or the monitor. Both should measure several (say, 2-5) volts AC if the PCB is generating a deflection signal. If there's no signal on the X & Y outputs, you can't very well expect the monitor to display anything.

That said, the OP's numbers appear suspect to me. It seems unlikely that there's over 20 volts of AC riding on top of about 10V of DC on any of those lines. Perhaps his autoranging meter is showing millivolts (mV) and he's not recognizing the difference?
 
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I can cuirtainly retest. But this is what I did. I put the black or common lead on the ground test point on the game board. Then placed the read mead on the Z-out/y,and x test points. I thught the voltage looked incorrect as well which is why I changed the battery and then questioned it it was AC or DC that I should be testing. iether way it did not look correct.

Lets assume for a minute that the voltage that I got was correct. What would cause that kind of voltage coming from the game board while still allowing the game to play blind and the correct voltage at the 5 volt test point? is that the MDAC chip? is there a way to test that chip?

I have not changed the caps on the game boards or monitors and don't know if/when they have been changed? could that cause the issue?
 
Sorry, Tried to put everything down and forgot the monitors.

The asteroids deluxe is a g05-802 version 5 board, the asteroids is a g05-801 but not sure of the version.

This, provided with your other info tells me that you have either a board or power supply problem. It is highly unlikely that 2 different monitor types would fail at the same time. It's not unheard of, just not likely.

Verify all of the voltages on your power brick, then your power supply. It is also pretty unlikely that both boards would fail identically at the same time. The most probable cause for both games to fail identically is a power supply issue.
Dok
 
I was able to get a nice working Tektronix 465 on the cheep but have not used a scope since college. I want to get to know this tool better and since a couple of folks have asked it I had a scope, can someone help me understand some simple test I can do with the scope to verify that the board is ok or how to test the monitor.

I think I hookup the leads to the X, Y gound test points on the board and should see the game image on the scope. is that correct, are there other test?
 
I was able to get a nice working Tektronix 465 on the cheep but have not used a scope since college. I want to get to know this tool better and since a couple of folks have asked it I had a scope, can someone help me understand some simple test I can do with the scope to verify that the board is ok or how to test the monitor.

I think I hookup the leads to the X, Y gound test points on the board and should see the game image on the scope. is that correct, are there other test?
Yes. Ch#1 goes to the X-out on the game PCB. Ch#2 goes to Y-out. One (or both) ground clips to the GND test point on the PCB. IIRC the Z input on the 465 is inverted from what you need. Just leave it disconnected for now. If those signals are right you should be able to recognize the game on your scope. Without the Z information, you'll see the retrace lines, all going to the center of the screen.
 
Have you checked the large sand resistors on the deflection chassis? Mine was acting just like you described, and in the end I needed to remove those resistors and jumper them.

The vector FAQ mentions removing them as an acceptable modification anyway.

On my V2000, they were near the edge of the pcb.

asteroids18.jpg
 
Yes. Ch#1 goes to the X-out on the game PCB. Ch#2 goes to Y-out. One (or both) ground clips to the GND test point on the PCB. IIRC the Z input on the 465 is inverted from what you need. Just leave it disconnected for now. If those signals are right you should be able to recognize the game on your scope. Without the Z information, you'll see the retrace lines, all going to the center of the screen.


Agreed; forget about the Z for now.

Set both chans to 1, 2 or 5 V/div for starters.

Set both chan to GND coupling, and center the beam.

Then change both chans to DC coupling.
 
I tried it this weekend and was not able to get anything but noise looking waveform. I will try a video tonight and post.

I know the channels work as I can see a nice ac wave when connected to a power source. I have not tried the last sugestion.

Also I noiticed that when I tried channel one and channel two seperately they showed horizanaly(i expected on hor and one vert line).

Is there anything else on the Tektronix 465 that I should make sure is set?
 
Turn the timebase knob (or whatever they call it on that scope... sweep, or time/div, maybe) all the way to the left, where it should indicate "XY". In any other timebase setting, both chans draw "horizontal" lines; only in XY mode does one of the drive the X-axis and the other the Y.
 
ok, So i did that and also downloaded and read the textronix manual. There is a nice section on setup for XY. The following is video is the results on the Asteroids. I verified the scope is working by testing each channel seperatly for 5 volts, and both leads. Np working like a champ. I tryed channel a and b both on ac and dc.

http://www.youtube.com/watch?v=WX9rACFw09w

I then tried my asteriods deluxe which is also having the same issue. When I test the asteroids deluxe, all I get is a dot in the center. With volt meter, on x and y it get the same voltage 13.5 volts dc, and 29 volts ac but the volts do not change up and down (I thought it was suppost to.)

I am not sure what to do next.
 
Hmm....try the same thing but unplug the monitor from the harness.

Plus, here's a simpler test. Put the game in test mode to draw a diamond crosshatch pattern. Then change the o'scope from XY mode to (totally guessing) 1ms/div. You should get a modified triangle wave (triangle with some flat regions) on both channels. Adjust the time base and the trigger controls to get a stable picture. Oh and set the trigger source to channel 1 or channel 2.
 
The monitor is unplugged. But in other forums I have seen that the voltage nneds to be fluctuating between .4 and 1.5 volts on the x and y outputs and I get a steady 13.5 volts. If that is the case do I have something wrong with the board. Either the dac or the voltage regulator?

Is there a way to test the dac with the scope?

I assume the voltage regulator is one of the three to package transitors and can be tested with a set of diode test?

Is there something else that could cause the steady 13.5 volts or is that ok?
 
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