Steve, that continuity check is not meant to be from points A to ground, it is between pairs of points A.? Two of the points A are BS170 drains, the other is one end of L502.? Checking pairs of these will show zero ohms if the coil soldering is good.? Bad soldering will show high ohms between one or more pairs.? Same goes for the two points B.
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Checking between each of those points and ground without the coil installed -
In the case of each of the two left-hand A points, without the coil installed, you are measuring the drains of pair of BS170 mosfets whose source is grounded.? Since these mosfets have an internal protection diode between source and drain, if you put your multimeter in diode-check mode, with the red terminal on ground and the black terminal on one of the points A, you should see the 0.6V or so diode drop.? With the probes the other way around, it should show open.
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For the right-hand A point, you should likely see something a bit different.? You are measuring through coil L502 through a pair of resistors to ground (R525,R526), about 57Kohms.? But you are also measuring (in parallel) through another mosfet source-drain (Q507) to +12V, which should show a different resistance depending on the polarity of your probes, due to its internal diode.? Sorry I can't do this measurement to say what it should be, since I currently don't have a card without the coil installed.
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I hope that was a little helpful, and you can find your issue.
Stan KC7XE
