VOGONS


First post, by ik777

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I bought a 8bit ym3812 soundcard and its condition is like picture attached.

What does I should to buy and soldering it? Is it a capaciter array? If so what type I should buy?

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    Found working one in vogons
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    Broken my card
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Reply 1 of 13, by luckybob

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considering its position on the card, and the fact its labeled with a "U", leads me to believe that it was an integrated amplifier part. You need the numbers from the missing part before you can fix it.

It is a mistake to think you can solve any major problems just with potatoes.

Reply 3 of 13, by ik777

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luckybob wrote:

considering its position on the card, and the fact its labeled with a "U", leads me to believe that it was an integrated amplifier part. You need the numbers from the missing part before you can fix it.

Is integrated amplifier used in sound card like this?

133MHz wrote:

Could it be the same as the "ACT-1" part that can be seen in the second picture?

The problem is the "ACT-1" part have logo of Covox. "ACT-1 Covox 56". I don"t think I exactly find it anywhere.

The thing in the picture looks to correct. (Every sound blaster have it.) But I don't know its exact capacity.

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Reply 4 of 13, by luckybob

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the thing you pictured is a resistor network, and are not used in soundcards, at least not in the audio out area.

in all likely hood, the missing part is a LM383, or something very similar. NS_LM383T_IC.jpg

It is a mistake to think you can solve any major problems just with potatoes.

Reply 5 of 13, by Jepael

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Definitely a complex IC. It is similar to the other module so it is something with custom markings. Impossible to say if it is a voltage regulator or some kind of amplifier. But it is definitely not a simple capacitor or resistor network.

Can you scan each side of the sound card so that we can see better where it connects to so we could have an idea how to replace it. I'd be glad to help fix it.

Reply 6 of 13, by DonutKing

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I have a Sound Master 2 and I can confirm that the missing component is indeed an ACT-1 COVOX-56 - U2 and U13 are the same component.

I don't know what it actually is though.

If you are squeamish, don't prod the beach rubble.

Reply 7 of 13, by Old Thrashbarg

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I hate to say it, but you may be SOL.

I don't think it's an amplifier IC, but even if it is, I wouldn't count on it being replaceable with a standard part. It looks like a thing called a "couplate". Very common in old radios/TVs. They basically combine a network of resistors, capacitors, and sometimes transistors, into a single molded unit (for various reasons... space saving, temperature stability, shielding, making more money off proprietary parts, etc.).

Normally they can be recreated fairly easily with discrete components, but that's only when you have a schematic to show exactly what it does. Reverse engineering them blindly tends to range from extremely difficult to impossible without special equipment. And I can't say I've ever run across a full schematic of a Covox card.

Reply 9 of 13, by ik777

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luckybob wrote:

It is lucky, I know Vogons and talk about these thing. Thank you.
I will go my country's local electronic part center first. Maybe I got a llitle chance to find it there.

Reply 11 of 13, by ik777

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Jepael wrote:

Can you still scan both sides of the card and post here? It will help determine where the part is connected and what it does.

I attached backside of it. (Foreside is easily find in my first attached or google.)
Let's guess what it does.

* Edit * Attach Foreside again, as you see it, this one was owned by Malik before. (World is too small) 😊

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Last edited by ik777 on 2013-08-21, 13:53. Edited 1 time in total.

Reply 12 of 13, by luckybob

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well lets do a bit of thinking. U5 is an LM358 which is a standard dual op-amp. pin 4 of U5 is ground therefore pin 4 of U2 is ground. U5-7 & U2-1 are connected, as well as U5-8 & U2-2. U5-8 is a 'VCC', given a choice between +5V and +12v my money is on +12v, this means U2-2 is also VCC. U5-7 is an output. thus U2-1 should be an input. so far we can rule out the LM383 as a replacement. 😜 I cant do much more without a good picture of the top. sorry.

It is a mistake to think you can solve any major problems just with potatoes.

Reply 13 of 13, by Jepael

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Yes we really need good picture from the top side. The bottom side could also be a bit better.

LM358 negative supply (and thus mystery component negative supply) can be ground but it can also be -5 or -12 volts. I can't determine that for sure.