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We all make mistakes... Keep better track of the screws!


-^CrossBow^-

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Won't got into too many details on this other than to state up front, that I try to be as transparent as possible with the work and services I provide. As a consequence of this, mistakes can and will happen. It is just a matter of when. One such big mistake happen to me this week while installing a very expensive DCDigital setup into a clients Dreamcast. I actually had the main installation done and was ready to test. However, in order for a DC to boot up, it requires that the cooling fan and GDRom drive be installed etc. So you kinda have to put it all back together in order to test an install like this.

Well I put in a few of the screws in various places to hold things down into place and then proceeded to fire up and test the DC. I got a power light and the controller and VMU beeped. But...nothing else. No drive spin up and nothing on the screen. No signal even being detected. And not just from the new HDMI output but nothing from the analog video side either! I quickly turned it off and tore the console back apart to see what was going on. I removed the DCDigtal setup and tested again. Same thing...nothing.

It was when I started to do the sniff test to see if anything had burned out that I found it... and what I found horrified me! What did I find? Well...this...

DC_Screw_Damage.jpg.0add1eca64bef07aad9bec5efb9bb809.jpg

The picture above shows at least 5 and likely 6 traces between the SH4 CPU and the GPU that were now torn and broken. How? Well notice the pattern of the tears in the traces and how it cuts into the PCB a little?

Yeap... that was done by a screw. It seems that even though I had carefully laid out the screws so that I knew what went to where, I mixed up the three longer screws used to hold the main board and shielding together along the back of the system, with the three shorter screws used to secure the GDRom in place. And because of that, the screw twisted down into the main board causing the damage you see above.

The other spot to the left where you see exposed copper is where I was trying to solder small kynar wire to repair these broken traces. But... no luck as the traces are just too small for the wiring I have on hand. And the large ICs on the DC are BGA type meaning Ball Grid Array. They are essentially surface mounted ICs with all of the contact points existing under the chip package so you can't just solder to pins or something on the bottom.

This required replacing out the main board in this particular case and provided a lesson I'm not likely to forget going forward to always be mindful and double or triple check your work and assembly process. 

And with that, the owner of this DC will soon be able to play their games again in wonderful HDMI output directly from the dreamcast in the very near future. According to the picture below, the self test fully passed on the replacement main board. The red spots are in fact little hearts that appear when everything is good. You get an X when things fail in the self test.

DC_DCDig_SelfTest_Pass.jpg.852480c096009235743423c88597c933.jpg

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I found a short length of multi-strand wire to be the perfect source for wire 5x smaller than the typical standard Kynar stuff. I found a length of it at a construction site and took it home. The strands gotta be 50 gauge or smaller. Finer than hair. Finer than earphone coil stuff.

 

I cut a 3" length and partly pulled out one strand. Makes for great dispenser-like action. Like white-out ribbon. Tack it down, pull/draw more out, tack it down. Bodge completed.

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Search for "0.1 mm wire", and you'll find suitable wire for repair. On the one side, you have vias (holes) that you can connect to.

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7 hours ago, 5-11under said:

Search for "0.1 mm wire", and you'll find suitable wire for repair. On the one side, you have vias (holes) that you can connect to.

Actually not really. See not all of the vias can be got to. They are offset and so every other one is under the BGA package. Addtionally, those vias don't go through to the other side. And the other end of the connection to the GPU doesn't have any vias there at all. Had that ben the case, I could have gotten away with using the 30awg kynar I have on hand now. I'm likely going to send it to another tech that likes working on micro stuff like this and let them have it. I already replaced out the main board for this project so the original is just a parts donor at this point. Then again, there isn't a lot on it that I can really use given the main chips really require a hot plate and better SMD station setup than I'm equipped to handle.

 

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29 minutes ago, -^CrossBow^- said:

Actually not really. See not all of the vias can be got to. They are offset and so every other one is under the BGA package. Addtionally, those vias don't go through to the other side. And the other end of the connection to the GPU doesn't have any vias there at all. Had that ben the case, I could have gotten away with using the 30awg kynar I have on hand now. I'm likely going to send it to another tech that likes working on micro stuff like this and let them have it. I already replaced out the main board for this project so the original is just a parts donor at this point. Then again, there isn't a lot on it that I can really use given the main chips really require a hot plate and better SMD station setup than I'm equipped to handle.

 

Regarding the vias: good point... I'm used to old school 2 layer boards. ;)

I'm happy at least that someone will try to repair. Much better than tossing, of course.

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