I am posting here because you will learn nothing; only comments / rant follow.
This mornig I run a heat gun brute-force salvage session on several extincted motherboards and some PCI cards. I was interested only in the connectors and the crystals. Just that. I accepted beforehand that whatever else would be lost.
No matter how you do it, whit a heat gun, the ICs and components get literally cooked even if the board is kept upside down for them to fall freely on a tray. They were even hot to touch. I read many comments saying that this way you can end with a bare board. While it is true it is not even worth the effort to have a collection of components cooked beyond hope.
The first to fall, from the group being heated up, were the tantalum caps and crystals. Some connectors, long ones, could take some time and a not so gentle tap on the board helped sometimes. When tapping the board, if any terminal got bent; the connector risked to stay there, hanging forever. More tapping.
Hot air from a smd rework station did not help at all. Evidently, air volume is too low to be of any use when applied to the solder side of the connectors.
On the contrary, gently heating the whole board with a more friendly heat gun, and then using a common desoldering technique, ICs and discretes come out in fairly well condition. I used this technique in the past with excellent results and just once today.
Motherboards found to differ a lot from each other. From one of them I got 5 crystals (one, the typical 32,768).
In many of them, the LM386 (SMD) was present.
And old one, still with 74LS logic and the AMI BIOS in two chips (ODD and EVEN)
Another motherboard, had NO crystal at all. How comes?
And the last: encouraged by the previous experiences, I was brave enough to recognize the deat of my PC. (It took me time. It happened some 20 years ago and it was my first one, where I learnt that BASIC was not available as in my Timex Sinclair.
I finally stripped the board and found an incredible (to me) 48-MHz crystal. The highest ever I could see in a MB.
Underlying connections between things do exist and it is up to you to notice them: the crystaless PC above and this one were of the same brand: WARRANTY VOID IF REMOVED.
This mornig I run a heat gun brute-force salvage session on several extincted motherboards and some PCI cards. I was interested only in the connectors and the crystals. Just that. I accepted beforehand that whatever else would be lost.
No matter how you do it, whit a heat gun, the ICs and components get literally cooked even if the board is kept upside down for them to fall freely on a tray. They were even hot to touch. I read many comments saying that this way you can end with a bare board. While it is true it is not even worth the effort to have a collection of components cooked beyond hope.
The first to fall, from the group being heated up, were the tantalum caps and crystals. Some connectors, long ones, could take some time and a not so gentle tap on the board helped sometimes. When tapping the board, if any terminal got bent; the connector risked to stay there, hanging forever. More tapping.
Hot air from a smd rework station did not help at all. Evidently, air volume is too low to be of any use when applied to the solder side of the connectors.
On the contrary, gently heating the whole board with a more friendly heat gun, and then using a common desoldering technique, ICs and discretes come out in fairly well condition. I used this technique in the past with excellent results and just once today.
Motherboards found to differ a lot from each other. From one of them I got 5 crystals (one, the typical 32,768).
In many of them, the LM386 (SMD) was present.
And old one, still with 74LS logic and the AMI BIOS in two chips (ODD and EVEN)
Another motherboard, had NO crystal at all. How comes?
And the last: encouraged by the previous experiences, I was brave enough to recognize the deat of my PC. (It took me time. It happened some 20 years ago and it was my first one, where I learnt that BASIC was not available as in my Timex Sinclair.
I finally stripped the board and found an incredible (to me) 48-MHz crystal. The highest ever I could see in a MB.
Underlying connections between things do exist and it is up to you to notice them: the crystaless PC above and this one were of the same brand: WARRANTY VOID IF REMOVED.
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