DK Jr. Video Issues

MunsonRoyE

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Hi All!

I am having a couple video issues with my DK Jr. The first problem is a little bit of motion around the edges of the image on the monitor. I thought this might be a problem with C606 so I replaced it and it didn't help.

The other problem I am having is that when the image switches from the Title screen to the High Score screen when no one is playing there is as split second when everything is a bunch of jumbled letters. The game plays fine with no issues at all, it's just during the screen switch when it happens.

Could both these things be caused by the same problem or are they separate issues? Thanks for the help.
 
Sounds like a dirty pin or socket. Reseat all of your socketed chips and the ribbon cables on the bottom of the boardset.
 
I reseated all the chips and cables from the PCB last night and it didn't help with the graphic glitch or the motion around the image. If I turn the vertical pot on the PCB so that the image is lower on the monitor, the motion gets worse. The closer the image is to the top, the better the image is.

Is the motion a pot issue or a power issue? Do I need to replace the pots on the PCB or recap the power supply? Could these problems be causing the graphic glitch as well?
 
did u install a high score save kit? if so make sure the z80 is properly one. I installed a HSS on my dk3 and the z80 wasnt firmly down and it caused the same graphic issues, slight glitch only in title and high score menu
 
Check your voltages at the power supply and on the board. It could be a little low. A video Of your screen in action would be very helpful for people to help you determine your actual issue.
 
I have replaced the Z80 with a new one and I am still getting the jumbled letters between the title and high score screen.

I also replaced the pots on the PCB and the screen is still vibrating from the left to right. If the screen is all the way to the right it hardly vibrates. The more I move it to the left the worse it gets. How do I check the voltage from the power supply and what should it be?
 
First of all you will need a multi meter, second, you will need a power supply pin out to be able to determine which leads are what. Also, I would suggest that you check/adjust your B+ volts Which should be @ 108VDC. There are plenty of threads about how to adjust your B+ on a Sanyo monitor. As for the PP-7B Power supply pinout.... Give me a few minutes and let me look for it.
 
OK I have tested the power supply and the wires. Thay all read .22 higher than what they say they are (as in +5.22) is this a problem or is that within where the rating is supposed to be?
 
OK I have tested the power supply and the wires. Thay all read .22 higher than what they say they are (as in +5.22) is this a problem or is that within where the rating is supposed to be?

Yeah, that's still good. The real test is whether or not your getting that voltage on the board.
 
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