Thread for my DK technical questions

Sir Kongsalot

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I got a DK without a monitor a couple of days ago, and I'm completely new to arcade machines. 90% of my electronics experience is with building/repairing PCs, and I get along well in that world, but I know this stuff is harder, especially when monitors get involved.

So I figured I'd make a thread for my initial questions, and more as they come up, since I'll surely have more.

QUESTION 1: without a monitor (and thus, without sound) is there any way to tell whether or not the board is actually functioning? It'd be nice if they had an LED on there or something!

My only idea has been the coin counter. With the power off, I flipped the coin lever and got nada as expected. Powered on the machine, flipped it again, and it went up by one!

So, if nothing else, I know the board's got a healthy current, but that doesn't mean I'm gonna be jumping barrels.

QUESTION 2: this power supply is damn near silent. As a PC guy, that makes me nervous. If you don't hear whirring, something's wrong. I hear nothing but the tiniest little whisper of a hum. Are these supposed to be that quiet, or is a fan that should be going, not going? If so, I obviously want to know sooner than later.

QUESTION 3: this is less of a technical question, but I figure I'll ask it here since I'm askin' stuff. The cabinet is missing both the serial plate and the serial number sticker on the CPU board. At first glance at the cabinet, I thought nothing of it (except to be sad that I didn't have my serial), but when I saw the board I felt there might be intent involved. Somebody else, who didn't know what kinds of questions to ask, picked up the machine for me, and I haven't talked to the owner yet (nobody else ever owned it), but could there be any reason that he might take the serials? Is this a "thing" that people do? When I talk to the guy, I'll ask, but if there's anything I could know ahead of time, I'd like to.
 
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1) The sound is completely separate from the monitor, the board has an onboard amp, the cab wiring should attach a speaker across the correct pins on the edge connector. Even an LED will only prove the board is getting some power, it doesnt prove it is running correctly or that the voltages are even close to correct. The coin meter incrementing doesnt really prove much I'm afraid.

2) Most arcade PSUs are whisper quiet, they have no fans in them, so a slight buzz is all you are likely to hear. You do need to confirm the voltages it is providing are correct at the board tho. From that era a noisy PSU is a dying PSU.

3) Cabinet may not be an original DK ie it was converted from another game, and it is possible the PCB may be a bootleg. Either way the PCB serial number stickers often just fall off due to age anyway. Is there any signs there ever was a serial plate on the cabinet?
 
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Thank you! This was helpful.

I was under the impression that, on a Nintendo cab, the sound was anything but "completely separate" from the monitor; that they were integrated. Since the volume control is part of the monitor, how exactly is the monitor related to the sound then? Should I connect the speaker and try powering up the machine to see if I hear anything? Will the game even boot without a monitor?

In fact - and I suppose I really should have asked this BEFORE ever plugging it in - is it at all risky/harmful to run just the board/marquee light without a monitor? Am I at risk of "underloading" the PS?

Again, all of my hands-on tech experience comes from PC stuff made in the 90s at the earliest. This is a box full of dinosaur bones to me, and it's intimidating. I love it, but I fear it. The problem is that I've almost certainly been "babied" by failsafes and foolproofing that may not have existed in older technology, and it may only be a matter of time until I take something for granted that I shouldn't.

I've never fried a circuit board but it's never too late to start, and I don't want it to be this one!

As for the serial plate, there are screw holes right where a DK serial plate "should" be (just above the FCC warning). And it's definitely an original DK cabinet, because the instruction sheet is still on the inside of the back door. Plus, it was purchased by the owner (pizza parlor guy) as a factory-fresh DK, and it went straight from him to me. I guess I'm taking his word for it, but I don't see any reason not to!

As for the board, it identifies itself as a TKG4-14 from Nintendo of America, and all the ROM chips have their stickers. The serial sticker is actually still there, just in a "hastily ripped off leaving only papery glue" state.
 
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Actually yes, I was wrong on the audio issue, an original DK uses an amp chip that is built into the monitor, its unusual in that respect.

It sounds like someone has tried to remove the identity of your cab, sounds like the serial plate was purposefully removed as was the sticker. The only two reasons I can think of are that the machine was stolen at some point in its history and this was done to make it untraceable, or the serial was a low number that they wanted to "migrate" to another cabinet for devious reasons.
 
Yeah, the serial thing is weird. It is said that one is an event, two is a coincidence, and three is a pattern, but I'm kinda feeling like two is enough to be a pattern in this case. I really know nothing about the people I bought this from, but for $75, a board they claimed was working fine, and great-condition parts (albeit VERY poor shape cab particle board), it didn't seem like too much of a risk. I could probably get $75 for this coin door and marquee alone. (Not that I'm gonna do any parting-out of this baby, I've got scores to submit and records to go after.)

The cabinet is also definitely the wrong shade of blue, yet there's no evidence of a paint job and evidence of there *not* being a paint job (the last bits of the sideart were still under the monitor bolts). I'm wondering if Nintendo used more than one shade of blue laminate during the run. So that's weird too, but I suppose that's a question for another subforum.

Do you have an opinion on the "powering the machine with no monitor" question?
 
1. Yes, but it will require diagnostic tools such as an O-Scope or a Logic Probe
2. That ps makes very little noise at all
3. Who knows, people remove serial plates for a variety of reasons. It means absolutely nothing.
4. The sound is integrated with the monitor on most Nintendo games, and definitely on a DK
5. Power up anything that you want, there is no danger if you do not have any loose wires hanging about.
6. There is nothing to connect the speaker to, without the monitor being present.
7. I have no clue what Womble is smoking, but I highly doubt that the machine was ever stolen or any other devious BS.
 
It sounds like you just need to find yourself a working Sanyo 20EZ monitor, throw it in the cab and see where you're at. - Barry
 
Scratch what I said about "original owner" - I (finally) just talked to the seller for the first time, and apparently my guy who picked the machine up for me misunderstood them. The couple I got it from are actually the THIRD owners (as far as they know), and this machine originally lived all the way on the other side of the country at a Hungry Howie's in Florida. So chain of custody is now anybody's guess.

Poor lady had somebody come look at the monitor (which was losing picture intermittently), he said we was going to cap it, and then he disappeared on them!

In any case, I guess it's high time I get myself a voltometer/logic probe if I'm going to get any more of these machines, or even if I stick with just this one. For all I know, the problem they were having might reside on the board and not the monitor, which means that it'll still be there when it's video'd up again, which means I'll have work to do.

(Crossing my fingers that it's just the monitor...)
 
The Sanyo monitors that come in these develop all sorts of video problems over time. Usually it is due to failing capacitors. More often than not recapping a Sanyo will fix the problem and look great again. Find a monitor or someone with a DK to test your board in if that is your concern. - Barry
 
It's alive!

I picked up a Sanyo 20-EZ from a local guy, wired the machine all together, and it would appear that I was NOT sold a lemon/dead-board machine. (Almost) everything is running great.

I have exactly three issues.

For now, I'll just ask about the first one, which is an audio issue:

When there is no audio connected, the machine is nearly silent. Just a little hum.

But when I've got the "brown wire" from the CPU board hooked up to the amp (the one on the EZ-20), and the amp to the speaker, I get a steady, oscillating, low-tone "wooowwmmm... wowwmmmm.... wowwmmm...." humming/buzzing from the speaker that never stops. This happens regardless of volume level.

But when I turn the volume up high, I hear an additional more high-pitched rapidly-oscillating chirp-chirp-chirp.

The attached zip file has an example of both.

My feeling is that the answer is "cap kit," because that seems to be the answer to everything, and that's fine, but I've never done a cap kit before (I've never so much as picked up a soldering iron before), and I feel like I'd rather save any sort of cap-kitting only for when it absolutely NEEDS to be done. This isn't "broken" enough to try to fix it (and risk truly breaking it).

The other thing I'd like to be able to do is easily control the volume on-the-fly. Sometimes I want sound, sometimes I don't, sometimes I want it louder, sometimes quieter. I'd like to be able to do this easily without having to take off the back door, or removing the bezel and reaching around the monitor.

In other words, I think I'd like to just use external speakers, rather than the cabinet amp/speakers, like what this guy has rigged:
http://www.youtube.com/watch?v=112LWpX4wHg

It seems that while this wouldn't fix the buzzing, it would be a solution to both of my problems.

At 40 seconds into the above video, you can see that he's got his "brown wire" connected to something, which then goes out to the speakers. What is that connector, and where can I get it?

And any other ideas about the buzzing?
 

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Just rebuild the audio board or if you don't want to do that buy a rebuilt one.

Both are available at arcadeshop. - Barry
 
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Using an ohm meter start by checking the values of your resistors in your sound section of your board.
 
Thanks for the responses. I will look into the audio issue at some point (still wondering about connecting to an external speaker though.)

Next up is this: I'm getting some sort of weird bleed on the top (only on the top) of my greens and blues. And it doesn't happen right away. Everything looks fine until the machine warms up, about 20 minutes or so.

It's most noticeable on characters. Check out the attached images. The red characters are rock solid, but the blue, yellow, and especially green, have those little extra "bits" on top. Look at "CREDIT 00".

I can put up a better image or two, but maybe it's something simple that you all will recognize. Is this a convergence adjustment? The pots on the neckboard? Or is it another "cap kit fix?"
 

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That is only a temp fix. Your colors are over saturated because someone couldn't see them and cranked up the color pots. Most likely this was due to failing caps. Could also be caused by not adjusting the color pots after a cap kit too.
 
The guy I bought this monitor from told me he just put a few new caps on. Not a full job, but a few.

He is an arcade tech by trade, so I'm not worried about his expertise in general, but all of these monitors have particular foibles and who knows if he's an expert on the Sanyo. I have no idea whether he checked the B+ after doing the caps, for example, which you have said needs to be done. I'll check that out next. I don't even have a multimeter yet! I didn't realize until I got this thing that checking voltages pretty much comes with the territory of owning on an old arcade machine...
 
Yeah, to be sure that you have a monitor that will service you trouble free for a long time, you have a few things to do:

1. verify that the B+ is 108 volts. Very important to do first.
2. Cap that audio board, if it hasn't been done. Or get someone to do it.
3. Adjust brightness. Turn it up until you see black background turning to gray/white, and then back it off until black is truly black.
4. Adjust colors. Start with all of the knobs at 50%, and the adjust 'slightly' to your taste.

To use your Donkey Kong board for color adjustment, just get a laptop or desktop computer display near your arcade monitor so you can do a side-by-side comparison of the title screen. Match the colors of the text on that screen and you should be good to go.

Here's a page with the manual for your monitor, as well as many others:

http://www.mikesarcade.com/arcade/monitors.html

Here's a good image of the high score screen:

attachment.php
 

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The guy I bought this monitor from told me he just put a few new caps on. Not a full job, but a few.

He is an arcade tech by trade, so I'm not worried about his expertise in general,

Obviously not a good one, or even a reputable one given the first statement above.

These half-assed guys that replace one or two caps calling themselves "Arcade Techs" makes me want to puke.

I just picked some food out of my teeth, I am a "Dental Hygienist".

Rebuild the monitor and do it right, or live with the problems associated with leaving it as is.
 
Obviously not a good one, or even a reputable one given the first statement above.

These half-assed guys that replace one or two caps calling themselves "Arcade Techs" makes me want to puke.

I just picked some food out of my teeth, I am a "Dental Hygienist".

Rebuild the monitor and do it right, or live with the problems associated with leaving it as is.

Hehe...Dave I take it you're in the 'replace them all' camp with respect to capacitors. :D That's cool.

It's an old argument - some techs meter out all the caps on the chassis and only replace those that need replacing. Some say replace everything. There are + and - to both ways of thinking.

But I don't think it necessarily means the tech is a hack. He could very well have tested everything and only replaced what was out of spec.
 
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