9267Re: Softrock 40/80 debug
- Mar 1, 2007How about this idea:
apply a high enough voltage to the suspicious via and fuse out the
If you reduce the voltage this is also a neat method for finding
shorts thru the voltage drop. Just need a voltmeter that can measure
millivolts voltage drops.
73, Tom DG8SAQ
--- In firstname.lastname@example.org, richard <richard.bown@...> wrote:
> Michael Karliner wrote:
> > I completed the build of my TXRX today, checked resistances and
> > initial current drain which seem OK. Upon connecting up to my
> > PC and Rocky, I'm getting faint signals, but they are symmetrical
> > around the center frequency, and connecting headphones to output
> > that I've got no signal on the tip side.
> > Unfortunately, I have not much in the way of test gear at the
> > moment, although I'm trying to borrow a scope.
> > Any words of wisdom or suggestions for debugging?
> > Thanks in advance Mike (G8LKD, when I get this working..)
> Here's an unusual way finding dry/unsoldered joints on surface
> Get yourself a 5 cms hypodermic needle, I find the green ones are
> and holding the plastic end
> gently run the point along the length of the IC over each pin. When
> go over a dry or unsoldedred joint
> you will hear the note change.
> so on a chip with 8 pins each side , on a good one you will hear
> ,ping ping, ect 8 times,
> as you find one thats dry the ping will sound much lower.
> You cant do it with a solid needle it needs to be hollow to work,
> being made of stainless steel
> you can always use the tip , made into a little hook to lift a leg
> IC for test purposes.
> Even a solder bridge between pins is enough to change the resonance
> you go over it.
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