Mario Brothers (In DK Jr. Cab) - Picture getting cut off

[msignor]

In my own defense -- I am new to the hobby.. however my first dive into these repairs was to rebuild both of my G07's in my Atari Games... That was cake. Additionally, I'm not a noob with soldering.. have a nice low wattage iron, etc etc. Been doing the solder thing for a while now...

To the point - I am not necessaraly jumping at the bit to rip the monitor apart. Definately more work than a G07 .. and taking it out alone seems to be pretty much a no go. I am also all for the preventative maintenance side of things too.

There is an ever so slight wobble in the picture.. but goes away when it warms up.. that I know is caps. I adjusted the knobs on the monitor last night and was able to get vertical sized.. but the horizontal position would basically stay the same or barely move to the right regardless of where I moved the middle pot. (middle of the 5).

What worries me is that you can see the pictures the image is not filling the whole screen at all.. I just don't know if a pot will make up for that much image.. Seems like something obvious to adjust at time of install..

I didn't attempt to get into the cage as it was late and I never worked on this type of machine before... so I need to check it out. Since I don't know the history of the machine, only hearsay I have no idea if it was even adjusted when it was converted or what..

I will try the board when I get home and see what happens!

 

[msignor]

hey guys,

Was able to adjust the picture size and center, all is well.

However, I get quite a crazy shake in the picture. It's not the hold, it definitely looks electrical.

My b+ is at 108 and slowly rises and settles at 109.3v

I stopped measuring and just put it all back together... What would be the cause of the shake? Is the B+ okay at 109?

-Matt

 

[Buffett]

sounds like failing caps.

have you done the cap kit.

if not i would before it get worse and fails totally.

B+ fluctuation is caused by bad/failing caps.

Peace
Buffett

 

[msignor]

Hey buffett,

Yep, the capkit you sent me was installed with the exception of the extra one, and the b+ pot.

Almost certain I pulled every single cap as you provided a pretty thourough kit.

Any clues on where to look or should I bust out the dmm and see if I can fond any bad caps?

Matt

 

[Buffett]

no the cap kit is good i have never had a bad cap with the ones i buy. i have seen many non cap problems after a cap kit. its always some other part on the way out or broke trace or cold solder joint.

it could be that Q901 and or IC601 are on the way out.

also it could be that your power supply is on its way out may be bad/failing with bad/weak caps in it. and your PCB is not getting enough power.

or you could have a cold solder joint or broke trace that after it warms up it causes it.

post a video so we can see the issue.

Peace
Buffett

 

[msignor]

Hey,

So I tried to take a video and between me shaking and the fact that it was hard to notice in the video itself I don't think any video I take can show the issue.

It literally shakes. seems to happen as more things come up on the screen. It wasn't quite this bad originally and it seems the capkit didn't change too much.

I tried the vhold and it may be a flaky pot.. although does now explain the b+ crepe I experience. Should I have replaced the b+ or w as that more of a fix it while your there kind of exchange?

How can I test the questionable components you mentioned?

Thanks!

Matt

 

[Buffett]

in my opinion you should always replace the B+ pot. that metal pot is the shittyest pot on the whole chassis. i always do when i repair one.

check this thread out it explains allot on how to test components on a sanyo.

http://forums.arcade-museum.com/showthread.php?t=211067


Peace
Buffett

 

[JamBurglar]

I'm fairly newb to repair so keep that in mind, but you might check the pots on the gameboard to see if they coorelate with the shakeyness. Those horizontal and vertical adjustment pots can cause some issues. If you have another nintendo PCB you might try to use that as a crosscheck.

Also, you were talking about the image not taking up the whole screen earlier in this thread. Nintendo games usually don't take up the whole screen and there is some degree of black boarder around the game (maybe 1/2 inch margin on the vertical and a little more than that on the horizontal.) I've seen a few games where people try to fill up their entire sceen with the image and the geometery on picture looks bad.

 

[msignor]

So I just had a quick thought.. You literally can not see any shaking on my video. It looks PERFECT.. I am wondering if this is a sync or hold type issue.. Usually you see a roll on videos of CRT's.. but mine ends up looking perfect.

Do the adjustment pots usually go bad?

Should I focus on the b+ crepe first? is the 1v difference really that crazy?