Re: 453 calibrator


On Wed, May 9, 2018 at 01:15 pm, Richard Knoppow wrote:

On my schematic BA and BB are shown right on the edge line of the board. They
look like they are connected together but are not.
You nailed it. you beat me to it. I did attribute it to a mistake but it is not. I am too aware of mistakes on prints, thy occur quite a bit in consumer. You see a wire that says 12 volts and then a inch or two away it says 0 volts. And it is no mistake like the one voltage is something else, I have seen them where it is simply not possible. And they don't really care.

Anyone who doesn't see it - observe the dot that indicates a connection there at BA and BB. Look at the other dots. This one is bigger. Well it is bigger because it is not a dot, it is a circle. The coax is grounded on that side but not on the other. This is not that uncommon.

I have to admit it fooled me up until very recently. I have shit eyesight, I thought I was used to it and I am to a point, but still I missed this.

That doesn't change the fact that I dismissed it as a mistake for troubleshooting purposes up to this point, and the resistors were the wrong value.

This is nothing. Poor eyesight contributed to me frying a 7603. I switched two of the plugs on the Z board and dumped 130 volts into the unobtanium horizontal IC. Luckily I had a parts donor handy. If not I would have been guilty of criminal involuntary scopicide. So this is nothing.

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