Hi,

I checked one of my Mk2a boards and it has a 1.2k (marked with a 122), and a zero-Ohm (marked 000), in the locations that Mark originally had indicated. The 1.2k is closest to the screw hole, the Zero-Ohm is next to it on the right.


In case you were wondering, the 122 marking on the resistor is 12 with 2 zeros. So that would be 1200 Ohms. There are 1000 Ohms in a k-Ohm. So the resistor has a value of 1.2k Ohms.

The same can be said for the larger yellow "block" looking solid Tantalum capacitors. A marking of 226 is 22 with 6 zeros. That is in pico-Farad (pF). So it would be 22,000,000 pF. There are 1,000,000 pF in a micro-Farad. So the capacitor has a value of 22uF. I know, geek stuff, get back on topic...


Mark is right, clean it up, snap another picture and maybe there is hope.

After the board is cleaned up, some measurements can be made with an Digital multi-meter to see some of the extent of the damage.

Since there isn't information on the layer stack-up and trace routing of the Printed Circuit Board, if it has caused excessive heat and has gone through the top layer to internal layers, it may not be fixable. Not that anything in that area is likely to be controlled impedance, but if the resin/glass weave separated (exceeding the Glass Transition (Tg) of 120 to 160 Deg C.), and allows adjacent layer routes to touch, it could be flaky, intermittent, or just a complete short. If the layer information was known, sometimes you can drill or open the traces (depends if there are planes - it looks like there is, you can't see through the board - in the same area though), and use wires to correct it.

Too bad that kind of data isn't available, it could be useful in these situations.

Keep hope, after you clean it, we'll know more, there's still a good chance it might be minor.


Ross