G05-802 Fade out

Darryl1970

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I have an Asteroids cabinet. When I repaired it, less than a year ago, I recapped the monitor, replaced the transistors, recapped the AR-1, and replaced the big blue. Everything seems to have worked fine for quite a while.

Recently, the monitor started fading out. If I wait a couple minutes, the picture fades back in. I have adjusted the brightness and contrast. Sometimes the picture completely fades out; other times, I can still see the ship and shots fired (very bright items).

I have read suggestions about cleaning all of the connector pins, but nothing I find seems to pinpoint what causes this issue. Does anybody know what the probable cause is? I would really like to minimize my troubleshooting time, as the holidays are coming quickly. There's SO MUCH to do!

I do not noticed the spot killer when it is dim, but the neck is glowing orange.

Thanks in advance for any help!
 
My guesses are the headers and bottle caps need a reflow or your brightness pot is going bad.
 
Also, did you use high quality caps, or 'el cheapo' cap kit ?

Even if an 'el cheapo' I don't know that it would be the caps yet.... though not sure if going in an out is consistent with caps.

Is there any blooming involved when the brightness changes, or do visible objects retain their size ? If they change sizes you could be losing HV. Similarly, do they stay sharp, or do they go out of focus with the change in brightness. Changing of sizes or loss of focus with the change in brightness could indicate flyback or hv diode problems.

There are others here that have more time on G05s than I, I've been pretty lucky so far in that I've mostly had to deal with cracked solder joints. Reflow them, do a cap kit, and back in business.
 
I likely know this one.

See posts #1 and #33 in this thread:

http://forums.arcade-museum.com/showthread.php?t=356350

Note that the above thread was for a 19v2000 deflection board, however this is nearly identical to the G05-802 board, so the same applies.

You should do the mod that removes the two large power resistors R100 and R101 (which should be done for any G05 or v2000 board). Just jumper straight pieces of wire across their terminals, on the solder side. You can physically clip out and remove the resistors too if you want.

Just disabling the resistors may be enough to solve the problem (or might solve it for a while, but if it still persists, you should also replace the Q500, Q501, and Q502 transistors as well, as they are likely worn out from the heat.

Q500, Q501 are TPS98, which can be replaced with MPSA06 (easy to get).

Q502 is 2N3906, which is easy to get.


-Andy
 
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I have an Asteroids cabinet. When I repaired it, less than a year ago, I recapped the monitor, replaced the transistors, recapped the AR-1, and replaced the big blue. Everything seems to have worked fine for quite a while.

Recently, the monitor started fading out. If I wait a couple minutes, the picture fades back in. I have adjusted the brightness and contrast. Sometimes the picture completely fades out; other times, I can still see the ship and shots fired (very bright items).

I have read suggestions about cleaning all of the connector pins, but nothing I find seems to pinpoint what causes this issue. Does anybody know what the probable cause is? I would really like to minimize my troubleshooting time, as the holidays are coming quickly. There's SO MUCH to do!

I do not noticed the spot killer when it is dim, but the neck is glowing orange.

Thanks in advance for any help!

if you need any pots, transistors, etc. i have them all in stock and zero ohm jumper wire if you don't have any long enough spent leads.
 
Most likely a hv board problem, z circuit, or fly back. I had a similar problem on an ad and it ended up being a resistor in the voltage divider for the brightness/contrast. The video bias should be 90ish volts coming from the hv board. Start there.
 
Thanks

Thanks everyone. I spent some time this morning on the machine. I pulled the chassis and HV cage. I re-flowed and I cleaned all of the connectors with alcohol. I also checked for a loose connection at the HV diode.

I believe the caps I used were pretty good quality, and the transistors were replaced at that time. I am going to keep my eye on this. If I have any trouble, I am going to check the reference to response #33 on the link above. I will also check the HV box more thoroughly. Once I know more, I will contribute any findings to this thread.

I don't notice "breathing", but I occasionally notice a quick size flash, like a flicker pulse, more than a steady breath. It is not consistent, and happens rarely.

After everything I did today, I adjusted the brightness. I turned the machine off for a few minutes. When I powered it up, it was dark again. I turned up the brightness higher than I wanted (I was running it a little dimmer, just to preserve the tube). It looks good, and I haven't noticed anything yet. I have it running downstairs.

I do enjoy working on my games, but the holidays have put me behind in other areas. I am trying for the quick fix/band-aid for now.

Thanks for all the input.
 
I reflowed, cleaned all of the connectors with 90% alcohol, checked the diode, and put it back together. Still had a little fade with the brightness/contrast where I had it.

I turned up the settings (I kept it moderate), and it played for the rest of the day. Haven't had any issues. Do these things REQUIRE more drive, or does this mean I probably have a weak component? Replaced all of the transistors with my capkit.
 
im pretty sure there is an article or interview where designer ed logg references this hardware flaw. cant recall what exactly was the issue but it had to do with vector monitors and constant focus or image. ill try looking it up.
thanks
blake
 
The reason I told you to disable the resistors is so that you can troubleshoot the issue step by step, in order to find the root cause. If you just start shotgunning things without doing it methodically, you will not get the information you need to know you actually fixed the problem (versus just covering up a symptom).

My guess is that you haven't actually solved the problem, but just covered it up by boosting the brightness.

Disable the resistors first (which should be done to these boards anyway), without changing anything else. See if that changes the behavior.

If not, then we start replacing things. Which transistors did you replace?
 
im pretty sure there is an article or interview where designer ed logg references this hardware flaw. cant recall what exactly was the issue but it had to do with vector monitors and constant focus or image. ill try looking it up.
thanks
blake


Are you thinking of the issue with the 6100? There was a bug with Tempest, which caused the screen to go blank during 2 player games, which was an issue with early versions of the 6100. It was fixed with a ROM update, and the hardware was changed in later versions of the monitor.
 
Are you thinking of the issue with the 6100? There was a bug with Tempest, which caused the screen to go blank during 2 player games, which was an issue with early versions of the 6100. It was fixed with a ROM update, and the hardware was changed in later versions of the monitor.

about 1:20 into this clip he mentions it. i thought there was a clip with him discussing it in more detail but here you go.
thanks
blake

https://m.youtube.com/watch?v=dHvA8oC4MNs
 
Just wanted to throw this out there. You may or may not already know this. It seems the CONTRAST adjustment is the more important of the two to get proper illumination.

http://www.crazykong.com/tech/bw_vector_monitor_faq.pdf

This is directly from The Black & White Vector Monitor FAQ and Guide
Version 1.2
April 03, 2002

ADJUSTMENTS

Brightness and Contrast:

To adjust the brightness and contrast on your monitor, turn brightness and contrast all the way down (counterclockwise). Then increase brightness until the images are barely visible. Adjust contrast for proper illumination.

By the way... I will be doing my very first recap and its going to be on a G05-802 from my ASTEROIDS very soon. I plan on doing the mod on those two ceramic resistors during the recap as well.
 
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