Donkey Kong/Sanyo 20EZ issues: Please help!

jcroach

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I picked up a Donkey Kong last weekend. This will be my first restoration project. I've been working assessing all the issues. I hope you all can help me with the monitor issues. Please keep in mind I know next to nothing about monitors and electronics.

So, here are the issues as I see them.

1. The monitor is very dim. I need to turn off all the ambient light in the room to see it. I even took the bezel off to take the pictures in this post. The previous owner said that it didn't work, but I think that was because they never saw the images on the monitor and the sound was disconnected.

2.The image sporadically sputters. Not sure exactly how to describe it. It flickers, there's a bright flash on the screen and there is a crackle type sound. See the video.

3. The "thud" sound when Donkey Kong slams onto the girders occasionally doesn't work.

4. The colors are way off.

Here's a video that shows the sputtering. On this video, the "thud" sound is working.: http://youtu.be/XquyKUjPGWk

I'm seeing more colors than shown on the video. Here's are some still images showing all that I can see.

picture.php

picture.php

picture.php


So, what do I need to do?

I figure that I'll need a cap-kit first of all. Which of my problem might this fix? I was thinking it might fix the dimness. Also, is the "Thud" sound an analog sound? If so then maybe re-capping the audio board on the monitor might help this issue?

What about the stuttering? Is this a common problem? This is what's got me most concerned.

I'm beginning in to think the colors issue might not be a monitor issue, but might be one or two bad PROMs instead. This web site: http://www.brasington.org/arcade/tech/dk/ makes me think I might want to replace at least the 2F PROM and maybe the 2E. Is there a way to test these before I buy one? Who do people buy their roms from? Steph at hobbyroms.com?

Also, totally not monitor related, but is there any benefit to replacing all of the fuses immediately?

Thanks in advance everyone!
 
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ask yourself:
What would "The Real Bob Roberts do?"

I would say, contact him and post this link. He will possibly tell you its a cap issue. Then work your way from there with replacing eproms and so on and so forth...
Good luck
 
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Wow, that's interesting. Looks like only blue is coming through? Tried adjusting the pots on the neckboard to see if you can get any response at all from the red or green guns?

Monitor might need a rejuv but if it's that bad off, the pots don't change it, and you don't have a rejuvenator handy or someone nearby with one and the CR-23 adaptor, at least the cap kit's a lot cheaper than a rejuv. Only reason I bought one for my Dr. Mario was because previous person had done all the other legwork on the monitor before I got to it...

But the rejuv did fix mine. :p

My youtube channel has vids.. http://www.youtube.com/user/Fraxcat?feature=mhee

So you can see there what my monitor looked like before...very similar to what yours looks like only I expect there's two colors low on yours. These guys know way more about this stuff than I do, but might be worth a shot before you go to the trouble to pull it all out and recap it.

Does the DK board have color pots on it as well? I've only got Vs. Unisystem boards...had to do a lot of adjustment on those as well on mine.
 
ask yourself:
What would "The Real Bob Roberts do?"

I would say, contact him and post this link. He will possibly tell you its a cap issue. Then work your way from there with replacing eproms and so on and so forth...
Good luck

Thanks. After I get some advice here I'll look to other sources for tips.


Have you turned up the screen voltage?

No and I'm not exactly sure how to do that. Is that the B+ voltage I keep reading about? I think I know how to find the pot and adjust it. I've read about the glue that is often on the pot and how it can be hard to turn. Any tips? How do I measure the voltage? Multimeter? I've read that it needs to be black lead on ground, red on TP91/BJ, is that correct? It needs to be 108v, right? Do you think it might be too high or too low?

Wow, that's interesting. Looks like only blue is coming through? Tried adjusting the pots on the neckboard to see if you can get any response at all from the red or green guns?

Monitor might need a rejuv but if it's that bad off, the pots don't change it, and you don't have a rejuvenator handy or someone nearby with one and the CR-23 adaptor, at least the cap kit's a lot cheaper than a rejuv. Only reason I bought one for my Dr. Mario was because previous person had done all the other legwork on the monitor before I got to it...

But the rejuv did fix mine. :p

My youtube channel has vids.. http://www.youtube.com/user/Fraxcat?feature=mhee

So you can see there what my monitor looked like before...very similar to what yours looks like only I expect there's two colors low on yours. These guys know way more about this stuff than I do, but might be worth a shot before you go to the trouble to pull it all out and recap it.

Does the DK board have color pots on it as well? I've only got Vs. Unisystem boards...had to do a lot of adjustment on those as well on mine.

I have not messed with the neck board pots, just the brightness pot. I know where the pots are located, but I couldn't see any labels and I couldn't find a chart on-line. Anyone have a chart handy?

I hope I don't need to do a monitor rejuvenation. The little I've read about it scares me. I'm scared enough to attempt to discharge it. I might need to find a professional to do that.

Should I attempt all other fixes, caps, B+ voltages, etc. before I do a rejuvenation?
 
I would guess since certain parts of the the screen such as the ladders are bright, its most definatley a cap kit fix.
 
If you have a tube tester, I'd check the picture tube to ensure it's not weak.

Try unplugging the video cable from the monitor and running it with no input. Since Nintendo monitors use inverted video, you should get a solid grey screen. You can ground each color pin individually at the video header to turn that gun full on. I've also seen broken solder joints at the video header on many monitors, check that too. If you can't get any bright colors on the screen like this, then your problem is definitely in the monitor.

One weird fault I found once was where someone had installed a Nintendo video inverter board in a game that didn't need one. The video cable went from the game board, to the inverter, then the inverter's non-invert out went to the monitor. Problem is, the inverter wasn't plugged in to power, so it just dragged down the signal. Everything looked real dim and washed out until that inverter board was removed.

A low B+ usually will result in a smaller picture, could also be a little dim. There is also a brightness pot on the chassis. Check the B+ (red probe lead to test point BJ, black one to the metal frame), you need 108v. If it's close, then that's not your problem.

I would suggest capping the monitor simply because these monitors have so many problems with caps. It might not solve your problem, but you should do it anyway. Cap it, then set the B+ properly, and see if you still have a dim picture.

Oh, and a word of warning on the Sanyo monitor... I know it has what looks like an AC line cord on it. But DO NOT plug that in anywhere other than the special socket in the bottom of the game. That's isolated, and it's 100v. If you plug it directly into the wall, you'll destroy a lot of parts in the power supply section of the monitor. Also, when taking the monitor apart, DON'T reverse the JB and JC plugs on the sound board. They're physically the same (but labelled). Mix them up and you'll burn tracks off the game board.

-Ian
 
I would guess since certain parts of the the screen such as the ladders are bright, its most definatley a cap kit fix.

That's what I'm hoping! Got my fingers crossed.

If you have a tube tester, I'd check the picture tube to ensure it's not weak.

Try unplugging the video cable from the monitor and running it with no input. Since Nintendo monitors use inverted video, you should get a solid grey screen. You can ground each color pin individually at the video header to turn that gun full on. I've also seen broken solder joints at the video header on many monitors, check that too. If you can't get any bright colors on the screen like this, then your problem is definitely in the monitor.

One weird fault I found once was where someone had installed a Nintendo video inverter board in a game that didn't need one. The video cable went from the game board, to the inverter, then the inverter's non-invert out went to the monitor. Problem is, the inverter wasn't plugged in to power, so it just dragged down the signal. Everything looked real dim and washed out until that inverter board was removed.

A low B+ usually will result in a smaller picture, could also be a little dim. There is also a brightness pot on the chassis. Check the B+ (red probe lead to test point BJ, black one to the metal frame), you need 108v. If it's close, then that's not your problem.

I would suggest capping the monitor simply because these monitors have so many problems with caps. It might not solve your problem, but you should do it anyway. Cap it, then set the B+ properly, and see if you still have a dim picture.

Oh, and a word of warning on the Sanyo monitor... I know it has what looks like an AC line cord on it. But DO NOT plug that in anywhere other than the special socket in the bottom of the game. That's isolated, and it's 100v. If you plug it directly into the wall, you'll destroy a lot of parts in the power supply section of the monitor. Also, when taking the monitor apart, DON'T reverse the JB and JC plugs on the sound board. They're physically the same (but labelled). Mix them up and you'll burn tracks off the game board.

-Ian

No, I don't have a tube tester. Hell, I don't even own a multi-meter or a soldering iron yet.

I've played with the brightness pot and I can get the grey screen. These images and video have the brightness all the way up.

If a low B+ results in a small image, what would a high B+ do?


Anyone have any thought on the stuttering and the bright flashes in the video?

Also, I just noticed that the jumbled text at the very beginning of the video is fairly bright. The reds and greens show up in the start much more so than the rest of the video. Does this mean anything?
 
Discharging the monitor "ain't no thang". I'm a noob like you, too. I don't have a multimeter yet either, and the only soldering I've ever done was to make my discharge tool and fix one wire on an edge connector lol. You can make the tool real easy with some thick Gauge copper wire soldered to a flathead screwdriver shaft that has a plastic or rubber handle. On the other end you solder the wire to an alligator clip. I used two because my wire was too thick for the clamps I bought. Just divided it down the middle and it looks like a hydra.

The solder blob actually broke free on mine but apparently there's still enough contact for it to work. Bob Roberts I think sells one where they actually drill through the shaft of the screwdriver to make it easier to assemble and better contact.

Pots on the neckboard going from back of the cab to the front should be:

Blue
Green
Red
Contrast
Brightness

If I'm not mistaken. hopefully you have someone handy to be looking at the monitor as you make adjustments or have a testbed.
 
That's what I'm hoping! Got my fingers crossed.
No, I don't have a tube tester. Hell, I don't even own a multi-meter or a soldering iron yet.
Ah. Well, you're going to need a soldering iron and a multimeter. The tube tester is more of a "nice to have". I wouldn't worry about trying to find one - if it turns out you need something done with your tube, someone local should be able to help you out.

If a low B+ results in a small image, what would a high B+ do?
If the B+ gets to around 120 or higher, the monitor goes into shutdown.

[/quote]
Anyone have any thought on the stuttering and the bright flashes in the video?

Also, I just noticed that the jumbled text at the very beginning of the video is fairly bright. The reds and greens show up in the start much more so than the rest of the video. Does this mean anything?[/QUOTE]

I don't know - can't play the video here. I assume you've already checked the solder joints at the video header, and verified that you don't have an inverter board wired in there for some reason.

-Ian
 
Discharging the monitor "ain't no thang". I'm a noob like you, too. I don't have a multimeter yet either, and the only soldering I've ever done was to make my discharge tool and fix one wire on an edge connector lol. You can make the tool real easy with some thick Gauge copper wire soldered to a flathead screwdriver shaft that has a plastic or rubber handle. On the other end you solder the wire to an alligator clip. I used two because my wire was too thick for the clamps I bought. Just divided it down the middle and it looks like a hydra.

Does not need to be thick wire.

Just use a regular aligator clip lead (has an alligator clip on each end). Clip it onto the shaft of a flat blade screwdriver, and clip the other end onto the frame.

-Ian
 
Try to turn up the screen adjustment. It's on the back on the flyback. Left pot is Focus and Right is Screen. There are 2 holes in the metal cage to access them.




"Anyone have any thought on the stuttering and the bright flashes in the video?"

Usually when you have a flash on the screen and the video jumps it's usually the flyback on these Sanyos.
 
I don't know - can't play the video here. I assume you've already checked the solder joints at the video header, and verified that you don't have an inverter board wired in there for some reason.

-Ian

Thank you. I'm going to check the pots and look for bad solder/unseated connections, broken leads/wire tonight after work and report back. Checking the B+ will have to wait until next weekend at least. Going to need to buy a multi-meter!
 
Pots on the neckboard going from back of the cab to the front should be:

Blue
Green
Red
Contrast
Brightness

Thank you!

Try to turn up the screen adjustment. It's on the back on the flyback. Left pot is Focus and Right is Screen. There are 2 holes in the metal cage to access them.

"Anyone have any thought on the stuttering and the bright flashes in the video?"

Usually when you have a flash on the screen and the video jumps it's usually the flyback on these Sanyos.

Thank you. I'll give that a shot. When you say "It's usually the flyback" do you mean it can be adjusted or the flyback is bad and has to be replaced?


Question for everyone, are these adjustments safe to do with the game running? I need it running to be able to tell if the adjustments are doing any good, right? I just need to stay away from the flyback cap/anode on the tube, right? Do I need any special tools or can I use just regular metal screwdrivers?
 
Safe? depends on where you place your hand. You can turn those by hand but I recommend the monitor adjusting tools (plasitic screw drivers) Don't put a metal screw driver in there while it's running you'll only regret it later should you slip.

You will need to adjust this with the monitor on.
 
Looks like only blue is coming through? Tried adjusting the pots on the neckboard to see if you can get any response at all from the red or green guns?

Bingo.

Holy cow, that was easy enough. I simply adjusted the color pots on the monitor neck board and the colors are absolutely brilliant! I was too excited to check anything else. I'll keep playing with it to see if the sputtering comes back. And the image appears squashed. I think I'll still need do a cap kit, but for now, success!


Thank you all!
 
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Bingo.

Holy cow, that was easy enough. I simply adjusted the color pots on the monitor neck board and the colors are absolutely brilliant! I was too excited to check anything else. I'll keep playing with it to see if the sputtering comes back. And the image appears squashed. I think I'll still need do a cap kit, but for now, success!


Thank you all!


Yeah, adjusting those shouldn't fix the sputtering (Looks like might just need to adjust the horizontal hold for that, maybe, if you're lucky..) or the image size.

Out of curiousity, how far did you have to move them...a little or quite a bit? On both my EZ20's, mine have to be up quite a bit of the way..guess I've got bad electron guns. Everyone seems to really like these monitors but mine...I dunno. Maybe the adoration of them is directly proportional to how much work you put into them getting them just right!? =\

*ediT* PS. Be real careful with the neckboards. Those things are way fragile from what I can tell, and you can even jack up the pins that come out of the tube if you bump it, and then you've got a glass brick if the neck gets cracked. :p
 
Yeah, adjusting those shouldn't fix the sputtering (Looks like might just need to adjust the horizontal hold for that, maybe, if you're lucky..) or the image size.

Out of curiousity, how far did you have to move them...a little or quite a bit? On both my EZ20's, mine have to be up quite a bit of the way..guess I've got bad electron guns. Everyone seems to really like these monitors but mine...I dunno. Maybe the adoration of them is directly proportional to how much work you put into them getting them just right!? =\

*ediT* PS. Be real careful with the neckboards. Those things are way fragile from what I can tell, and you can even jack up the pins that come out of the tube if you bump it, and then you've got a glass brick if the neck gets cracked. :p

No, unfortunately neither of those adjustments worked.

I cranked the color pots all the way up. It might not have needed to, but I didn't have anyone home to watch the screen for me. I'll turn them down a little bit when my wife is home to help.

And thanks for the tip on the neckboard. I'm actually treating everything with kid gloves because I have no idea what I'm doing!
 
I'm actually treating everything with kid gloves because I have no idea what I'm doing!

Well, you should read up a bit on that. Ignoring the flyback and anode wire (which are 20KV+), there are voltages on that neckboard (like focus) that will bite you really hard...
 
Well, you should read up a bit on that. Ignoring the flyback and anode wire (which are 20KV+), there are voltages on that neckboard (like focus) that will bite you really hard...

True, but not on the adjustment knobs - you'd have to touch the solder points at the back of the CRT socket. And even then, Focus isn't going to be there - that wire enters through the top of the socket, and the connection is insulated.

Not that you can't get buzzed pretty good by doing so - the G2 voltage is exposed, but it's not like you're going to get zapped across the room or anything.

-Ian
 
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