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Old 7th April 2013, 12:11 AM   #1
TehDude is offline TehDude  United States
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Default Replacing the caps in a Sega Game Gear

Hi,
I have a question that requires some expertise.

I recently bought a Sega Game Gear. They are known for failing audio caps (it's a early 1990s device, that should say it all).

Usually, people just install whichever capacitor they can find on the cheap in those things, but I recently had the honor of comparing an original Gameboy (the bulky thing, build completely from through-hole parts) vs. a Gameboy Color (100% SMD). The Gameboy Color sounds thin and crappy, while the original Gameboy cranks out it's warm signature sound. Sure, there are other factors that influence this, but that's not the point.

So, I not only want (or rather have to) to replace the capacitors, but also improve the sound a bit in the process. The audio amp is based on a TDA2822M:
Click the image to open in full size.
Quote:
Audio amplifier used in Sega Gamegear. The 470F caps were changed to 47F on the gamegear's sound-ampifier PCB and they go bad (C=0,R>>1). Therefore no current and thus no sound anymore. The other electrolytic caps may be bad as well, but they don't seem that critical. The small caps are SMD parts and still work (most likely ceramic or whatever).
Here are the required capacitors:
Click the image to open in full size.

I had a look at the Elna Silmic II, but it only comes in 100uF 6.3V, so I'd have to get 47uF 6.3V (instead of 4V).

Do you have any recommendation as to which capacitors would fit this purpose? The sound should be warm and bassy.

The board originally has SMD caps installed, it would be awesome if your recomendation comes in that form factor, but most people install regular caps, and that wouldn't be a problem.

What I've found so far in audio-grade SMD parts are the Nichicon UQ and the Elna RFV (SILMIC).
Click the image to open in full size.

Thanks!

Last edited by TehDude; 7th April 2013 at 01:03 AM.
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Old 7th April 2013, 11:18 PM   #2
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I've put a lot of 25 V caps instead of 3 v and 6 v electrolytic caps in my Hammond amps. Sound better, probably because they are not 40 years old up and dried up like to the originals. So far so good. Don't know how big your speaker is, but a 470 uf series cap is pretty small for an 8 ohm woofer. I've installed a couple of hundred e-caps in the last 3 years in tube amps, transistor amps and radios, this computer's mainboard, the disk drive in this computer, etc etc etc. I don't worry about "audio" in the advertising, the only "audio" caps anybody has tried to sell me is mcmelectronics that don't have any other specs, like service life etc. The Hammond and Wurlitzer stuff the caps seems to go bad after 20 years, the dynakit stuff the caps went bad in 8 years at 2000 hours a year, the computer stuff started going bad in 4 years, some PCAT power supplies I haven't repaired had obvious electrolyitic cap problems at two years. As a result, I only buy caps now specified at >3000 hours service life. It is amazing how many 500 hour caps are stocked at distributors; get the customer out the door at the lowest cost, I suppose, and don't worry about tomorrow. Lately I've been buying mostly Panasonic, Nichicon, Rubicon, although a few CDE's and Multicomp's I bought in 2010 are still doing okay. I have a large collection of dead Semi motor drives in nice stainless boxes with big heat sinks that the Cornell Dublier flat pack MLPE1192 caps all went bad on cold mornings at about 4 years life with big puddles of cap slime in the bottom of the box. Semi's fault for buying to price I suppose, they are bankrupt now. The Nichicons in TB Woods motor drives seemed to last fine in oven motor drive compartments (very hot) for 10 years or more.
newark.com (farnell Usa) has both radial lead and SMD caps: I only install leaded because that is all I have equipment and training to deal with. If you can install SMD I admire your skill. You won't have any trouble finding, them. By contrast, I count myself luckly to find leaded caps, even though the tall transistor voltage cans in the Wurlitzers went the way of the dodo bird before I could afford a $5500 organ (now worth $25 because it only whimpers).
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Last edited by indianajo; 7th April 2013 at 11:27 PM.
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Old 8th April 2013, 12:48 AM   #3
JMFahey is online now JMFahey  Argentina
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Quote:
Originally Posted by TehDude View Post
I recently bought a Sega Game Gear. They are known for failing audio caps (it's a early 1990s device, that should say it all).

Usually, people just install whichever capacitor they can find on the cheap in those things, but I recently had the honor of comparing an original Gameboy (the bulky thing, build completely from through-hole parts) vs. a Gameboy Color (100% SMD). The Gameboy Color sounds thin and crappy, while the original Gameboy cranks out it's warm signature sound. Sure, there are other factors that influence this, but that's not the point.
Warm sound? A Gameboy?

Quote:
So, I not only want (or rather have to) to replace the capacitors, but also improve the sound a bit in the process.
I think you can.

Quote:
The audio amp is based on a TDA2822M:
Here are the required capacitors:
......................
I had a look at the Elna Silmic II, but it only comes in 100uF 6.3V, so I'd have to get 47uF 6.3V (instead of 4V).
Why the terribly inadequate 47uF value?
The original factory schematic calls for 470uF.
Nothing to write home about, but at least passable in a tiny plastic box with tiny speakers.
Try to upgrade to Factory specs.

Quote:
Do you have any recommendation as to which capacitors would fit this purpose?
Yes, *If* space allows it, try to get 470uF there.
Even using 220uF or (ugh!!) 100uF would be an improvement.

Quote:
The sound should be warm and bassy.


Quote:
The board originally has SMD caps installed, it would be awesome if your recomendation comes in that form factor, but most people install regular caps, and that wouldn't be a problem.
Cool, hope you can fit there something better.
The question remains whether the fitted speakers *do* have any extra bass extension available, which is a very iffy thing.

Quote:
What I've found so far in audio-grade SMD parts are the Nichicon UQ and the Elna RFV (SILMIC).
Labels, hype and brand are relatively minor points.
Can't hurt, but the real problem is parts **rating/specs**, a.k.a "part value".
If you don't change it, nothing changes.
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Old 8th April 2013, 06:32 AM   #4
TehDude is offline TehDude  United States
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Quote:
Originally Posted by indianajo View Post
I only install leaded because that is all I have equipment and training to deal with. If you can install SMD I admire your skill.
They aren't really minuscule SMD parts, just small cans with flat leads to mount them on the surface:
Click the image to open in full size.

The old Gameboy has more room for the sound to resonate and a larger speaker, that might be the culprit. Of course a Gameboy is no high-end audio device, yet different models have their own, distinctive sounds.

I have a 2.1 sound system from a laptop laying around, I might as well try to fit that into the Game Gear. The thing is huge and should ave enough space.
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Old 9th April 2013, 06:13 PM   #5
TehDude is offline TehDude  United States
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I've got that exempt from the web, but reading the data sheet, what was realized here is this one:
Click the image to open in full size.

Three 100uFs are present, but they swapped 0.1uF with 47uF. Yet, I want to replace the speaker with something made out of this. If it doesn't fit, there's a subwoofer that's 1/2 the length of this one. They're from a MacBook Pro and sound great in there, and are probably the best you can cramp in a Game Gear.
Click the image to open in full size.
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Old 9th April 2013, 09:29 PM   #6
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The 0.1 uf on the outputs of the amps are just RF filters, IMHO. A 32 ohm speaker may be common in games but isn't elsewhere. I doubt if that little amp has enough current to drive a lower impedance (ohms). The 100 uf on the inputs are to balance the drive from the input. If the 100 uf caps leak, they will cut your output some and possibly cause distortion as the output crams against the power supply rail.
Amps with enough current to drive an 8 ohm speaker with any power tend to have a heat tab to be screwed to a heat sink.
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Old 10th April 2013, 10:30 PM   #7
badman is offline badman  United States
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Is this for use as a gaming device or are you making it into some kind of hacker portable radio?
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Old 11th April 2013, 12:58 AM   #8
TehDude is offline TehDude  United States
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I may explain: The Sega Game Gear is a portable gaming device much like a Nintendo Gameboy and in a sense the the predecessor of the Sony PSP, but has a larger LCD color screen than a Gameboy (and FWIW, games that are less targeted to children).
Click the image to open in full size.

What happens is that the capacitors in the device start leaking after nearly 25 years, resulting in no sound and bad contrast on the screen. In the case of the sound, it's the fault of the two 47uF caps.

Now I'm in the process of fixing mine to output sound again and have a crisper screen, but I want improve it while doing so.

As far as the display goes, you can replace the CFL backlight with an LED backlight, which consumes far less power (it runs on 6 AA batteries).

For the sound, I basically came to this forum to hear what you have to say about it. The circuit itself doesn't look too bad for a device like this, given that the same TDA2822M was used for i.e. much larger PC speakers. It provides 2x1W into 8 ohm at 9V.

As I have the above speakers laying around, I want to replace the single 1" speaker in the Game Gear with them if they physically fit and happen to sound better, otherwise find two higher-quality 1" speakers, if that even happens to exist.

The challenge here is that you are mostly constrained by space for both speakers and amp, so I intend to keep the amp and and replace the caps in the amp and power supply with Silmic IIs as a reasonable upgrade. Whether it makes a difference or not, at least the sound will work again. After all JMFarhey gave the advice that all caps are the same.

The speakers for the MacBook Pro should be among the higher quality speakers in this size, but I know that JBL makes laptop speakers as well. If you have any suggestions about tiny speakers in the 1-2" range, let me know.

Last edited by TehDude; 11th April 2013 at 01:18 AM.
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Old 11th April 2013, 02:11 AM   #9
badman is offline badman  United States
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Why not use an atari lynx?

Big robust media quality, and Zarlor Mercenary is a great shooter.
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