So let's begin the desoldering session !

And there's the chip ! ... Wait what's that green thing ?

Oh god, this isn't looking good at all !

And here is another chip !

Under it the board was apparently safe ... but I desoldered that chip because the pins were a little bit rusty (though not as bad as the first one 🤣)

Now that they're removed, I'm wondering how could I clean them. I tried vinegar but it didn't seem to help (I didn't try this for too long, I don't want to break them). I know that solder integrates flux and that it can remove corrosion but I don't really want to heat them up again unless I really need to, I really don't want to break them or even just their pins.

Any help on how to clean the chips and the board itself is welcome ^^

Okay so I tried several things to clean both the card and the chips.

I tried solder flux which worked great but after cleaning there is still some corrosion left that doesn't want to leave

I tried white vinegar which didn't seem to have any effect

And I just tried lemon juice+salt. It didn't seem to have an effect though when I poured it on the board it started to smell funny so I guess that it reacted a little bit
I think the next thing I'll try is acetone. Of course I won't use it everywhere, just on the chips and the pads.

One thing I wondered is how does the dream SAM9233 sound ? I can't find any records of that chip on the internet and so I wondered what sound it can produce

Use high concentration isopropynol and gently scrub with a Q-Tip

Deksor wrote:

One thing I wondered is how does the dream SAM9233 sound ? I can't find any records of that chip on the internet and so I wondered what sound it can produce

Search for Hizon DB333 or Formosa AudioStar-16 Wave, which are two wave tables using the 9233. I own the Hizon DB333 and while limited by a too-small 4 mbit sample ROM, it's not that bad at all.

Would you mind telling me what to buy and how to accomplish that feat (The COMPUMEDIA removing) ?

A Hot air station is on its way to my home as recently I found out a chipset with 3 loose legs in one side, and six in adjacence.
I believe this is working as isolators and in consequence my motherboard isn't POSTing.

From what I've seen (my first time doing this operation), I have two roads:
-Split solder paste on those legs and then hot air
-Remove the chip like you did

The easier, the better...
Thank you for your support and time.

Talking about rust, white vinegar won't do good to precision parts, but it doesn't have the power to destroy those legs. After all, there isn't much
rust in your chip. It's improbable that something goes wrong, even if you soak those legs for days.
The fact is you don't want any risk, so I agree about using isopropynol. It's good enough to clean them up in your case.
Lemon juice is a joke. That doesn't do anything and since my last experience, I vowed only to do lemonade to drink. 😐

The guy restoring a Adlib Clone just got the spirit: Used vinegar and even scouring pad. Nicely done.

Now that you said - "Of course I won't use it everywhere..." What about using vinegar everywhere in the card ?
Just too agressive and the card would get killed ?

You can also use drag soldering.
https://www.youtube.com/watch?v=588iV07nEdM

Hot air can be excellent for desoldering, though.

To desolder the chip, I just used the hot air station and nothing else. At this moment I don't have solder paste so I didn't use that technique. I saw somebody on YouTube removing cache chips by going in circles (or square) around the chip and he tried to push it from times to times. Once it was hot enough, the chip moved and so it was desoldered. The guy also said not to go over the middle the chip because it would kill it. I don't if that's true but I didn't want to try. The only thing I've used is that orange tape which can resist to high temperatures. Why ? Because otherwise some of the smd components around the chip would have gone too. The tape blocks the airflow and so makes the solder on these unable to melt because they're too cold

I trained myself with a dead socket 7 board before doing anything to that card though

When you look to the GPU reflow videos you can see that these people are using something that I'd call a "board grill" to avoid thermal shock, but these things are realy expensive. I guess that poor man's solution would be to pre-heat the board with an oven. Though my board is a 2 layers board only so there's not munch risk in doing that I guess.

At first I feared that the rusty part would stay in place while the rest would move and so taking the pins off the chip but hopefully it did not.

There's some other chips that I think I will remove such as the 74LS245D chip on the right because all the small holes under it seem to be corroded as well. In fact I wonder if I won't try to remove most of the stuff found on that board to really clean it properly and being able to look for broken traces better

Good luck! I'm looking forward to seeing the results.

Deksor wrote:

At this moment I don't have solder paste so I didn't use that technique.

Deksor: I meant to use solder paste to solder the problematic legs, not to desolder the stuck ones.
Is this a stupid idea and removing the chip completely is mandatory in my case ?
I repeat - This is a finick nOOb talking to you, take it easy... 😀

I saw somebody on YouTube removing cache chips by going in circles (or square) around the chip and he tried to push it from times to times. Once it was hot enough, the chip moved and so it was desoldered. The guy also said not to go over the middle the chip because it would kill it.

Makes a lot of sense. Naturally that center zone is a dead zone for this work
and we don't want much heat inside the chip. By the way, you didn't say the temperatures...please, I'm clueless.

The only thing I've used is that orange tape which can resist to high temperatures. Why ? Because otherwise some of the smd components around the chip would have gone too. The tape blocks the airflow and so makes the solder on these unable to melt because they're too cold

I did think so. Just like tin foil. Name ?

I trained myself with a dead socket 7 board before doing anything to that card though

I'll be practicing with both dead Gigabyte LGA 775 / M919 VIP and dripping sweat 😠
Thermal shock while reflowing? Damn. I'll read about that.

gdjacobs wrote:

You can also use drag soldering.
Hot air can be excellent for desoldering, though.

Speaking about the drag soldering tutorial:
That guy is awesome, a terrific video.
I didn't know flux - not quite aware of its magic, but whatever.

Do I need a special tip for my soldering iron? I'm not a fast learner. Heard something like "large teasle tip".
Anyway, right now Sir Dave is showing me how to use hot air, too. 😎
In the name of Vogons 😈 😈 😈, greetings for trying to help people who are not even close to your league. I know how tough this can be.

Sorry if I sounded rude, that wasn't what I wanted to sound like ... I thought that you wanted to desolder it completely with solder paste ^^

You know, I'm a noob too, I've just seen a some videos and I decided to give it a try ^^. Otherwise this card is dead so I'm not really hurting it

I've set the temperature to 500°C. It may sound high but since I'm not directly touching it, I think that air cools down quickly. At 400°C I wasn't able to desolder anything.

I don't know the name of the tape, I'll tell you later

I've heared that heating up just a small part of the board makes it get bigger (I don't know how to say that) and so it can snap some of the traces. But that's mostly said for modern hardware with multiple layers. On these old boards with only 2 sides and no internal layers, checking for broken traces is munch easier (and that's what I'd need to do anyways once the board is clean

It's Kapton tape - https://en.wikipedia.org/wiki/Kapton

Yes you're right

Not rude at all.
I was just asking you to be patient along the way.
Besides, I'm the one hijacking your thread 😀 😀 😈

Deksor wrote:

I've set the temperature to 500°C. It may sound high but since I'm not directly touching it, I think that air cools down quickly. At 400°C I wasn't able to desolder anything.

275C is the min to melt solder and doubling it appears to be a bad idea to remove components like the COMPUMEDIA chip.
There is a tool for this to work faster, but again, I don't know its name (in Y shape) 😠
A good thing you've been told old boards have more endurance.

sirlemonhead wrote:

It's Kapton tape - https://en.wikipedia.org/wiki/Kapton

So that's what I wanted: 250ml of flux, Kapton and solder paste 😎
Thanks.

I'm really happy with the hot air station and practicing with dead motherboards was successful.
So far I could remove a voltage regulator: Pre-heated his area for 30 seconds with 300C and after 40 seconds (using around 370C), it came off.
Removing diode and crystals was a no brainer. I just didn't go for my wrecked chipset, yet.
Any hints for me to improve? The hot air station is a basic model.

Deksor wrote:

On these old boards with only 2 sides and no internal layers, checking for broken traces is munch easier (and that's what I'd need to do anyways once the board is clean

Great. If you have the time, please describe how you go through this ordeal.

And Yeah, good luck releasing your card from that gross! And enjoy DREAM.
I don't know about your DREAM. What I know SC-8600 SAM9407 is truly wonderful. I still
remember me in my little corner playing Duke3D with many sound cards in order to choose the best.
I picked SAM9407 because the percussion was amazing and bright for this particular game.

I know that solder do melt at 275°C, but since the 500°C air have to travel some distance, hit the solder and heat it, etc, I guess that it cools down too munch to melt anything. I attempted to desolder the chip on my dead socket 7 board at 400°C and I wasn't able to desolder anything. Also my hot air station being very cheap (I paid ~40€ for it), it may also just be poorly adjusted.

Though I still fear to be frying them as I never removed a chip from a working board to desolder it and then re-solder it and check if it still works

Even though if I can't fix that board at the end, it will defitely have taught me a lot of thing with retro corroded hardware repair. I just found a rusty Atari STf that will surely need to have some of it's traces replaced ^^

I've heared the sound that the SAM9407 does in a YouTube video and yeah it sounds awesome. Though this is not exactly the same chip so the sound it makes is unknown but probably very nice ! I've got some YMF724 and 744 sound cards but this sounds great too 😀

Here's some news : I removed some more chips and tried different techniques of cleaning. Here's how it looks like now :

As you can see, I had to peel off some of the solder mask. I also tined some parts of the copper that was then visible. Now I guess that my job is to check if every traces are ok. However the fact that some of the solder mask went off bothers me, I'd like to put something to cover it and avoid further corrosion