m00dawg
Offline
Texas

I did some Googling and it's probably that I fail at Google but I didn't really find much information on replacing caps in the DMG? Specifically cap-kits (not unlike the ones you can get for old arcade monitors) that anyone might sell? I found trying to get the values off the original caps a bit of a chore as they are small and in various orientations to make it hard to read.

My current DMG has some audio artifacts beyond what I would expect - I certainly don't remember it being that bad, and I am wondering if new caps might be a way to go. I replaced the caps on my NES-001 mainboard (and the one big one on the RF board since I could get to it) and it certainly made a difference with improving the video quality. Was hoping something similar for the GB (except more so for the audio).

Thanks!

Tim

Alley Beach
Offline
clovis CA

the most you can do ( that i know of) is actually bypassing some caps. just below the crystal theres 2 caps labeled c3 and c4, both rated at 1uf. take them out, and bridge the holes. shazam, its clear (to some)

kitsch
Offline
matt's mind

haha, i actually sourced these and had everything to go, put them into a box when school got crazy last fall, and haven't gotten them back out again (cap-kits)...

i'll make a post-it and pull them out and get those done, i managed to find the weird sizes and everything... 

it probably would help, yes.  the caps are out-of-date now, on the play it louds even (this year, if one uses the typical 15 year life)

*makes note on hand*

2PLAYER
Offline
Rhode Island

Posted a while back on by passing those caps:
The mod: http://2playermusic.tumblr.com/post/403 … dmg-moddin
Audio comparison: http://2playermusic.tumblr.com/post/403 … arisons-on
Visualization: http://2playermusic.tumblr.com/post/407 … io-testing

Though, if I remember correctly, you had the CPU-02 dmg. Not sure if this would actually do anything to help you out

Theta_Frost
Offline
Milwaukee, WI

Replacing caps on these systems is always a good idea.  I'd buy a kit.  In fact I'd appreciate more for various systems, i.e. I know of a people selling kits for Atari ST and Amiga but not much else.  Maybe a cap value database would be a good idea?  I recorded the values from some of my Genesis's.

m00dawg
Offline
Texas

Thanks for the info all! For some reason I wasn't getting e-mail updates on this thread (that reason being I forgot to click subscribe hmm) but some good stuff here thanks! ASM mentioned to me off-list that it might be a bit cumbersome to replace all the caps so it might be a "do it if you have to" thing.

@2Player, I do indeed have a DMG-02, but I was also able to score an 06 (oh man did that make a difference!) that's in better shape overall I think. That'll be the one I do all the mods on I suspect.

@Kitch - thanks and you're welcome! (Saw the mention on the Twitterverse) I'll likely be grabbing these up at some point soon! Looking forward to the NES one as well (I replaced a few already but not all the ones in the RF module since I don't know of a good way to get that sucker off) and it made a noticeable difference.

Dragoon
Offline
Germany, Trier

why do you tried to read the values of the caps, there signed right on the pcb at each cap...

m00dawg
Offline
Texas

Kitsch now has a cap-kit for DMG's so it's moot. That said, I don't recall seeing values for all the caps on the PCBs though *shrug*

kitsch
Offline
matt's mind

there are caps for all of them in the kit, the kit is sold out as of yesterday though, need to put more together now!

Dragoon
Offline
Germany, Trier

can you please explain me, what its about, changing them to newer ones?
Everyone says like "its a good idea", but that answer isn't enough for me, i want to know exactly.
whats the positive effect of it?

Grymmtymm
Offline
KC

caps get old, lose performance, leak chemicals and ruin traces

m00dawg
Offline
Texas

To elaborate a bit more, the electrolytic caps are what we are talking about specifically. They are based on a liquid electrolyte which slowly seeps out and evaporates away. How fast is a factor of build quality, temperature, voltage, etc. In some cases, their capability to hold their rated capacitance can drop significantly in as little as 5 years.

The best example I can think of is with an old arcade monitor. When the electrolytic caps are no longer providing enough capacitance, you will start to see color issues, lack of contrast and picture wobble or waves. In the audio realm bad caps will usually cause AC hum, lack of good response to transients (say a huge bass-bomb right after a quiet part as an example, or a huge cymbal crash).

For the GameBoy, the difference isn't as significant as it was for the NES in my case. But replacing the caps made a difference in both, and if your GB is old, or you suspect you're not getting the sound quality you should be, can't hurt to give it a go if you are comfortable with a soldering iron. Even if it doesn't improve the sound, it may be adding live to your GameBoy by making sure your caps are back into spec and the circuits can get the proper power they need.

Dragoon
Offline
Germany, Trier

Well every DMG is old, isn't it wink 1989 I suppose...

mhhh, ich got many DMGs, no lack of color, because there isn't any ^^
no lack of contrast, no lines, no waves...and significant changes in audio quality...thats an audiophile listener thing i guess.
If I would hear a buzz or swoosh, I would know it.
I think the caps have a life-time of 10~15 years from factory, good 'ol caps from back in the days wink

What caps are obstructed in the DMG and which one do you prefer to change with? I think there are great differences, which one to use.

m00dawg
Offline
Texas

Right so basically every DMG probably needs a cap kit, depending on use. Electrolytics will dry out even if on the shelf (though at a slower rate) so some of the oldest DMGs, even if they were never used, may still need replacement caps.

As far as which ones, if you're going to spend the time opening things up and replacing a few caps, may as well replace them all. Any of the ones that involve the voltage doubler for the LCD I would replace (as that can impact the sound quality I believe). Unfortunately, those are the more difficult ones to replace since some of the solder joints are under that thin LCD cable.

All the other ones are generally so easy to get to and caps are so cheap might as well swap them out. Definitely swap out any along the audio path.

If you were referring to using another type (like tantalum over aluminum electrolytic), I can't say. Since DMG's aren't made any more, I opt to be somewhat conservative there and just replace the caps with the same capacitance. Room permitting, you could use caps with a higher voltage rating and use a higher end brand (like Panasonic). I wouldn't do much else though if it were me.

Dragoon
Offline
Germany, Trier

so as i mod a lot of stuff, it be cheaper for me to get those caps in a set of hundert, instead of buying those kits...cause 1 cap is expensive and more will get cheaper.

so, it isn't a difference putting paperfoil, oil or alu caps in there? only durability maybe?

You said something about the voltage doubler, where exactly are they placed?

What about the resistors, would you prefer chaning them too?

m00dawg
Offline
Texas

As I said above, I wouldn't change the type of cap if it were me. Different cap types have different characteristics - noise, ESR, responsiveness, durability, frequency rejection. Without knowing the purpose of each cap, it's hard to make a decision on if another cap may might be more appropriate. It /probably/ won't hurt anything changing caps so long as they are spec'd our properly (especially if you use tantalums, which are known to catch fire if subjected to voltages higher than their rating) but, as I said, if it were me, I'd go with high end electrolytics if I was concerned about it.

There is no need to replace the resistors that I can say. Only the electrolytics dry up and cause problems as a result. The resistors on the board are likely in spec and I don't see things improving substantially by replacing those (say with ones that have a higher tolerance or something).

The voltage doubler stuff would be around the LCD. As I also said, if in doubt, just replace them all smile It's inexpensive to do and you can have all the caps swapped out within an hour.