Diffferent techniques in troubleshooting

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. The city has a water leak. They are not sure where the leak is. >They can not dig up a whole city block to find it so they use a >clever trick. They put two microphones about 50 feet apart where the >leak seems to be. Then then record the random sound of water hissing >out of the pipe. The two mic rophones are wired to left and right >channel of the recorder. By adjusting the time delay of the right or >left microphone they can find the sweet sp ot where the random noise >from one microphone matches the random noise of the other >microphone. Once the delay is know they know where the leak is > within 1 or 2 feet. That is a clever trick. "

. It was one of those ancient coaxial feeders, and it ran a good quarter m ile through the woods, maybe more, it's been a while. How to find the brea k?

C. It makes a noise like a gunshot when the arc jumps the gap. You walk t he route of the line (which you never know exactly because your drawings ar e always a little sketchy) and listen.

he arc welded the break back together. No more pulses, no way to find the spot, we just turned the power back on and let it go.

Is the glass half empty or is the glass half full ? The way I see it you re paired the fault by sending a large EM pulse down the line knowing well tha t this would weld the two wires together therefore fixing the problem. That is the way I would write up the repair report.

For me, it is purely a hobby, with the occasional household appliance or ve hicular item intruding on occasion. So 'production' is not an issue, and un less I see my worth, as it were, at very little, spending 12 hours and $20 in parts restoring a pre WW2 Hallicrafters ot 5 hours & $10 on a Dynaco ST1

20 is a fool's game were it not a hobby. But, as therapy, and as a source o f quiet satisfaction, it is unsurpassed.

I tend to be fairly methodical, diagnostics, the repair based on same. Then about a 12-hour burn to make sure whatever it is is actually ready for pol ite society. No beancounters, no cost limits - a 'bulk' purchase might be

100 very common-value caps, or 20 common transistors, which might last a co uple of years.

Peter Wieck Melrose Park, PA

The st120 is an interesting beast. I did repair one in the 80's AFTER someone made swiss cheese out of it.

Yeah - "interesting" is a mild descriptive of a beast that can range from a purring kitten to a rabid wolverine in its behavior. I have three examples in my immediate possession - not one from the same lot or with matching boards...

Peter Wieck Melrose Park, PA

ST-120's.

They're like Harley Davidson motorcycles.

If you love them, if you can fix them, if you don't mind the smell of carburetor cleaner and the oil stains on your living room floor,

go for it!

Mark Z.