G05-802 no neck glow in asteroids cabinet

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Long time lurker, first time poster.

I've been struggling with putting a g05-802 in my asteroids cab.

I can't figure out why I don't have neck glow, also spot killer is not on.

I think I've ruled out everything and maybe it's just a bad tube, which I'm not sure what I could do about that.

The previous 801 monitor was arcing at the neck after a roof leak dripped directly on it. After different attempts to save it I assumed the tube was bad and got rid of it. I was kind of scared of the arcing neck
-located an 802 that was parted from an asteroids deluxe in unknown condition although looks very clean, converted harness from g05-801 to use a g05-802
-no blown fuses anywhere in the game
-this is an issue 6 deflection board
-getting heater voltage around 6v from p500 pins 9 and 10 (and the power brick and p100)
-I get heater line continuity from p500 to j800 "neck board"
-Game board X and Y voltages are fine
-tested all the frame transistors and many transistors on the deflection board which all test fine. Althought this shouldn't matter to just get neck glow
-Game plays blind
-if I unhook the connector to the game board then spot killer will light up
-I can't find any visible defects with the tube
 
First, be aware that neck glow can be dim and hard to see on these. Make sure you're looking with the room lights out.

Second, neck glow on these is created from the 6.3V AC from the power brick. It's the same voltage that powers the coin door lights. It is in no way related to the HV cage. It just comes in from the main harness, goes through the deflection board, and to the tube.

It is also in no way related to the spot killer. From what you are describing, your XY deflection is working fine, because the spot killer is out when there's good XY signaling from the game board, and it goes on when you unplug the game board. (You can also press and hold the reset button on the game board as another way to test the spot killer. The LED should turn on as long as you hold the reset button down, and then go off when you release reset.) If all of this is the case, then you're basically 100% sure that the XY system is working. However these are completely separate from Z, and from neck glow.

You say you have 'heater voltage around 6v from p500 pins 9 and 10'. That's good. If you take the connector that plugs into P500, and test continuity from pin 9 to 10 (basically looking 'into' the heater of the tube), do you have continuity? That will tell you that the heater is intact.

If all that is good, one thing that might be happening is a bad connection in the connector for P500. Shine a bright light into the end of the connector, where the pins enter. Look at the contacts inside the connector housing. Make sure none are bent, mashed, pushed in, or are otherwise out of line with the others. Normally in a good case, you should see all contacts lined up with each other. But a semi-common issue on all of the connectors in these b/w monitors is that the contacts can get smashed if someone tried to put the connector on crooked. And the contacts get bent enough that they won't actually make contact when the connector is plugged onto the header.

Something you can do to test this is unplug the tube socket connector, and unplug the main 12-pin monitor connector, and then test continuity across pins 9 and 10 of the mated connector, with all power off. It's important to disconnect the tube, as well as the main cab harness, as either of these can cause false readings. But if the contacts are bent, you should be able to see it via visual inspection of the contacts looking into the connector.

One more check: What happens if you turn up the brightness and contrast pots on the board all the way to max, with everything connected and powered normally? Do you see anything at all on the screen?

Bad tubes are actually fairly rare. And if you do have a bad tube, you want to make sure you've done measurements to confirm that conclusively, as you don't want to be sending a tube to the dump unless you are 100% sure, and know exactly how it's bad (which all can be determined via measurement.)
 
You say you have 'heater voltage around 6v from p500 pins 9 and 10'. That's good. If you take the connector that plugs into P500, and test continuity from pin 9 to 10 (basically looking 'into' the heater of the tube), do you have continuity? That will tell you that the heater is intact.

I haven't tried this yet. I unpluggedthe connector to p500 and checked continuity between pins 9 and 10 in the connector and did not get continuity. I guess that means my heater is not intact then?
 
I haven't tried this yet. I unpluggedthe connector to p500 and checked continuity between pins 9 and 10 in the connector and did not get continuity. I guess that means my heater is not intact then?


It means that there is a break somewhere in that loop to, through, and back from the tube.

It could mean the heater is not intact. But it could also mean that there's a bad connection between the wires and the tube socket, or the tube socket and the tube.

To tell which it is, one thing you can do is remove the tube socket, figure out which are the heater pins, and see if you have continuity between those pins. If you do, the heater itself is ok, and the issue is in the wiring or the socket itself.

It's not uncommon to have bad connections between the socket and the heater pins. The heater gets hot, and this can fatigue the socket contacts where they grab the heater pins. And/or the heater pins can get dirty. The socket on my own Asteroids Deluxe can be flaky at times, and will cause the picture to fade, and I have to reseat it to get the image back. If I had to venture a guess, the heater is likely ok. But you'll have to measure it to tell.
 
I took the tube socket out, found the 2 pins for the heater protruding from the tube and they do not continuity. I suppose this is the end for this tube isn't it?

I think I may want to just get rid of this asteroids as it's cursed.
 
Which 2 pins did you test?
I tested the 2 pins that are either side of the nub or key or whatever it is on the socket. I got continuity on the 2 sockets to the brown and black wires from p500. The socket continuity is nice and strong, but trying to text continuity on these 2 pins produces no continuity.
 

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Yeah, I'd say that's pretty conclusive then. Looks like that tube is toast.

Good job getting to the root cause, at least. Sorry the outcome isn't a good one.
 
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