Motorola M7000 issues

timberterror

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My sprint 1 has some issues with it that I am trying to resolve.

Issue 1 - occasionally the picture will get larger for a few seconds, sometimes it's large-small-large-small then it looks fine.

Issue 2 - when it's doing the above, the picture will sometimes look very fuzzy like it's totally out of focus.

Issue 3 - On the right side where you can see the edge of the picture it looks wavy and unstable. The line that defines the right side moves and looks unstable.

This is what I have done so far and none of these helped the issue..

1 - standard cap kit
2 - replace can capacitor
3 - replace regulator and horizontal and vertical output transistors.
4 - adjusted it. B+ is dead on at 73

It doesn't seem to be the gameboard itself, when I plug in my test 19" motorola the picture is perfect as far as I can tell and doesn't have the above symptoms.

For the hell of it I replaced the regulator and the large filter caps on the game pcb with no change.

I love this game and would really like to get it working perfect. Any ideas??????

Thanks, Barry
 
What is the B+ doing when the picture enlarges? I have seen B+ shift causing the picture to bloom like you are describing. The solution was to replace the fly, but that was on a very different chassis than the one you are working on (U2000). I have also seen a failing tantalum cap cause the same issue (Neotec).
 
I just went out and fired it up. The B+ came right up to 73. I watched the screen for a while and when the screen fluctuated the B+ did not. I played with the adjustments a bit - vert size, vert lin, horizontal ossc, contrast and bright. I was able to get a picture I'm pretty happy with besides some blur in the white lettering and the B+ was stable at 73.2.

I notice a little humbar in the picture and at least for the few minutes it was on it didn't pulse except for a bit when it was first turned on. - Barry
 
The blooming could be caused by a failing high voltage diode...or the high voltage diode not making good contact with it's socket. Remove it and clean the ends and the socket. Make sure the socket is getting a good "bite" onto the diode.

The fuzziness could be the tube. If you're having to overdrive the contrast or brightness....fuzz can happen. Know anyone who can rejuvenate the tube?

Edward
 
The blooming could be caused by a failing high voltage diode...or the high voltage diode not making good contact with it's socket. Remove it and clean the ends and the socket. Make sure the socket is getting a good "bite" onto the diode.

The fuzziness could be the tube. If you're having to overdrive the contrast or brightness....fuzz can happen. Know anyone who can rejuvenate the tube?

Edward

I'll check the diode to the tube tomorrow, is the diode available if it's bad?

There are a couple guys locally that can rejuv, so I may have to try that.

-Barry
 
I pulled the anode from the tube amd it was loose. I cleaned the area around it, bent the clamp a bit and have a tight connection there. I pulled the diode and made sure it was connected tight. Now that I think about it, when I was playing the game before the screen would look fine and when I shifted hard it would start freaking out so a loose connection makes sense. Turned it back on and so far no issues. Now I'll just get someone to rejuv it when I can. Thanks guys.- Barry
 

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