K6100 has odd image shift.

BustedArcade

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Hi everyone,
I have a K6100 that has for lack of a better term, oscillation in the image. The image appears to shake in an orbital motion.

It works and it is playable but it just has that odd shake that I find distracting.

Has anyone seen that behavior before? This is a first for me.

Thanks.
 
1) What game is it in?

2) Do you have an analog scope?

3) Can you provide a short video?

4) Has there been any extra ground leads added anywhere?

5) Have you measured the +/-15V outputs of the 7815/7915 regulators on the game board?


Bill B.
 
1) What game is it in?
Space Duel
2) Do you have an analog scope?
No I do not.
3) Can you provide a short video?
Yes I can. I will take one today.
4) Has there been any extra ground leads added anywhere?
No there have not.
5) Have you measured the +/-15V outputs of the 7815/7915 regulators on the game board?


Bill B.
No I have not but I can also do that today and report back.

Thanks.
 
Hi everyone,
I have a K6100 that has for lack of a better term, oscillation in the image. The image appears to shake in an orbital motion.

It works and it is playable but it just has that odd shake that I find distracting.

Has anyone seen that behavior before? This is a first for me.

Thanks.

Got another big blue cap?
Check the neckboard plugs?
 
I have a Tempest board that causes the shakes (squiggly characters) and confirmed it across three K6100s. Have you tried another board?

Scott C.
 
5) Have you measured the +/-15V outputs of the 7815/7915 regulators on the game board?


Bill B.

I have -15.27 from the 7915 and +15.04 from the 7815.

I did notice a peculiar behavior today while I worked on it. When I turned the volume up any time the ship exploded the image would shake violently. With the volume turned down this didn't happen. I slapped various parts of the cabinet as well as around and under the monitor chassis to see if it was caused by vibration but nothing happened.

Maybe there's an issue in the power supply that it can't supply enough current and the voltage drops causing that shake?

Maybe everything I'm seeing is related.
 
I have -15.27 from the 7915 and +15.04 from the 7815.

I did notice a peculiar behavior today while I worked on it. When I turned the volume up any time the ship exploded the image would shake violently. With the volume turned down this didn't happen. I slapped various parts of the cabinet as well as around and under the monitor chassis to see if it was caused by vibration but nothing happened.

Maybe there's an issue in the power supply that it can't supply enough current and the voltage drops causing that shake?

Maybe everything I'm seeing is related.

I would doubt that the shaking image is related to the power supply. The monitor operates on the non-regulated 50VAC/CT supply and the ARII audio amplifiers run from the unregulated but rectified and filtered 10.3VDC supply. The game PCB runs on regulated +5VDC. Since these supplies are so isolated from each other, I would not expect the audio volume to directly effect the monitor. I think that it's much more likely that the physical vibration of the speakers is influencing a bad connection or cracked solder joint in the monitor. If you can provide a video showing the problem, it might help us determine whether the problem is in the deflection or HV boards. It could be just cracked solder around the monitor video input port header pins. Have you reflowed the solder on all of the header pins on the monitor deflection board? Cracked solder around the video input header pins (viewed on solder side) often appears as tiny circular cracks around the pins. This is an extremely common problem and reflowing the header pins is in the top 5 tips when it comes to repairing monitors and game PCBs.

Bill B.
 
Update/Solved:

I tried everyone's suggestions. I reflowed everything and I capped it since I was already reflowing the boards. Nothing seemed to correct the constant oscillation and violent shake during explosions and other loud events. I even substituted a known good ARII, another power brick, and basically anything I had an extra of to try and isolate the cause.

If I physically hit the monitor it would make no difference but yet loud sounds made it go crazy. I was having a difficult time believing it was vibration, especially after reflowing everything. I took the monitor out of the cabinet, placed it on a table, connected it with the extender and even then loud events would make it shake. Lower volume settings would have no effect and would reduce the constant oscillation.

During this entire process I was also frustrated with the volume pot, it was difficult to adjust sometimes and the volume would appear to change volume on its own. I went to my parts box and grabbed another Space Duel service panel. I noticed that the volume pot's construction would allow adjustment from the rear and in this case that would be easier since I could rotate the arm rather then trying to grab the thin shaft (my fingers were hurting already).

When I went back the cabinet and tried to adjust the pot from the rear the problem became obvious... the service panel was bent down and the volume pot was grounding out against the coin box. I could not believe it, when you would turn up the volume to a higher level the arm would come in direct contact with the coin box and that's when the image would get really bad during louder events.

I bent the service panel up so that the pot was no longer anywhere close to the coin box and bam, gorgeous steady image regardless of the action.

So there you go... it was the volume pot grounding out. Learn something everyday... Thank you to everyone for the suggestions.
 
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