K7900 Question

Riptor

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Im working on a K7900 and this thing has what appears to be a crt brightner? Can anyone verify this and let me know if it came with this from the factory.
 
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I dunno about "came from the factory" but I've seen many with that and I just leave it alone...
 
I changed the flyback with a good used one I had here and left that out. Im pretty sure its something that was added. I have seen these for sale before and my thought is they are a quick fix for a chassis with weak caps.
I checked all the caps on the chassis and found two bad caps. I was marginal and another completely open. The monitor wouldnt sync before but now I have a steady picture but its very strange looking. Im going to throw this magic box back on and see what happens.
If that doesnt help I will post a screenshot.
 
I dunno. I know the K7915 is medium-res.

I found a for sale thread where it mentions a K7901 in a Super Hang-On, so that would appear to be standard-res...
 
Adjusting the Horiz Hold doesn't help? You may have a board issue. Do you have a different game to try it with?
 
Looks like a sync issue and a board issue. If you are using a Pac board, make sure that you only have the sync on the -H and not tied to both like on a G07.
 
Definitly not a board issue. Maybe the sync is not hooked up right, I will try changing it.
I dont have the sync wires combined, they are going in seperate.
 
Im working on a K7900 and this thing has what appears to be a crt brightner? Can anyone verify this and let me know if it came with this from the factory.

Those things were added by Wells at the factory. They were used to help level out the screen voltage on gun games when the screen flashed. On early gun games the screen would bounce or get a nasty case of retrace when the monitor would flash. These things would help minimize that.

Matt
 
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Some screen shots of what its doing.....

You sure that's a 7901? Looks like you've either got a board problem (which you said you don't) or that's medium res monitor chassis. Do you have caps soldered onto the bottom of the deflection board?

Now that I think more about it that chassis looks like the ones used in Toobin which would be Medium res...

Matt
 
ok, well i still need to do a cap kit on a 7901 as well as a 7935 and neither have that focus divider , so standard res

any advice?
 
Rise from your grave!!!..... thread resurrection for a quick question

Super thread ressurection, but wanted to get the attention of someone who had some experience with this.

Just got in 4 7000 chassis with broken tubes so I stripped them. 3 of them said "k7601" on the sticker and one said "7901" on the sticker, but they all look identical and had yoke readings that were the same.

Is there any difference? I found this manual which seems to indicate that they are the same. Only difference (that I could see) was in the type of metal frame.

Just curious!

Thanks!
 
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