qbert K4900 problem :(

itetcboo

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So I finally got me a qbert. Been waiting for years to pick one up locally and finally the stars aligned. lol

Anyways it has some kind of horizontal sync issue as near as I can tell. I just put in a cap kit (never done this chassis just 2 GO7's) from Bob roberts (quick shipping as usual from Bob) and anyways it looks about the same as it did before. Possibly a bit more stable but still not great. Its a bit jumpy and also shifted down a bit and what not as well. Its a cell phone pic but you get the idea. If it wasnt jumpy and it was shifted up and straight with the world the pic looks like it would look great.

Any ideas? Any suggestions?
 

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How do you have the sync hooked up? When you did the cap kit, did you reflow all the cold solder, specifically the video input pins and vertical area behind the flyback?
 
I did reflow the 6 signal input pins and the 4 larger pins that are near the flyback (are those the ones you are talking about). As far as how I have it hooked up it all looks factory like no one has every touched much of anything on this qbert. The chassis looked virgin. The 3 pin connector just above the 6 pin signal input though which I believe is for syn use has nothing plugged into it. Its bare. Also after it has been running for a while it starts to sync less and the picture looks worse if that helps at all.
 
I checked my voltages coming off the power supply and it all looked pretty good. My 5v + was 5.04 but I adjusted it down. Also the 12v was more like 11.8 but that seemed pretty close. I guess I will hook up a different monitor to the machine just to check that the output on a known good CRT is good and then go from there. I was really hoping that that cap kit would do the trick but clearly I am going to have to dig deeper. I did remove the main game board and polish up all the edge connectors which looked like they needed it but that didn't seem to help. Any other suggestions?
 
Well, there IS a way to tap into composite negative sync out of the Q*Bert boards instead of using the current separate positive sync. You could always try that if you can't figure it out.

But I'd look at your video ground and sync signal. Possible your sync pots, too...
 
Qbert monitor works just fine off of a 60 in 1

I hooked up my 60 in 1 board to my qberts K4900 monitor and it looks just fine (upside down but thats to be expected) the picture looked great and I didnt even have to adjust anything. I then ran my qberts vid signal cable over to my Super Pac-man which has the exact same monitor which I have had no problems with and the picture is all distorted in a similar way. I tried to adjust it out with the h sync and the v sync pots but I couldnt get it to even look as good as it does on qberts K4900.

So either I need to somehow sync the output of my qbert board to CRT somehow? Or get that sync thing that is sold by jrok? Or is it possible someone rewired things wrong on the video output coming out of my qbert board? I checked and its wired in the same way as it is where it plugs into the qbert board. Also it all looks grounded as near as I can tell.

Ideas? Suggestions?
 
She works!!!

I pulled the filter board and anything that looked suspect solder joint wise I redid. Put her all back together and the picture looks really good. I am now going to get it all dialed in but as near as I can tell I now have a perfectly functioning Qbert and I am stoked!

Thanks again to everyone for all the help. Write up on the machine to follow as soon as I get time.
 
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