Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #21   Report Post  
Old January 2nd 16, 03:14 PM posted to sci.electronics.repair
external usenet poster
 
First recorded activity by DIYBanter: Nov 2013
Posts: 221
Default Diffferent techniques in troubleshooting

On Saturday, January 2, 2016 at 2:04:06 AM UTC-5, wrote:
"Another unrelated problem. You being an engineer will enjoy this one. 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 microphones 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 spot 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. "


HA, HAHAHAHAHAH

HydroTDR


Hah, I can top that one.

We had a power outage, traced to a break somewhere in an underground line. It was one of those ancient coaxial feeders, and it ran a good quarter mile through the woods, maybe more, it's been a while. How to find the break?

We hired this specialist with a thumper, which is a pulsed high voltage DC. It makes a noise like a gunshot when the arc jumps the gap. You walk the route of the line (which you never know exactly because your drawings are always a little sketchy) and listen.

Usually this works. Not this time - it arced for a while, then somehow the 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.


  #22   Report Post  
Old January 2nd 16, 08:34 PM posted to sci.electronics.repair
external usenet poster
 
First recorded activity by DIYBanter: Dec 2015
Posts: 41
Default Diffferent techniques in troubleshooting

On Saturday, January 2, 2016 at 10:14:26 AM UTC-5, Tim R wrote:
On Saturday, January 2, 2016 at 2:04:06 AM UTC-5, wrote:
"Another unrelated problem. You being an engineer will enjoy this one.. 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 microphones 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 spot 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. "


HA, HAHAHAHAHAH

HydroTDR


Hah, I can top that one.

We had a power outage, traced to a break somewhere in an underground line.. It was one of those ancient coaxial feeders, and it ran a good quarter mile through the woods, maybe more, it's been a while. How to find the break?

We hired this specialist with a thumper, which is a pulsed high voltage DC. It makes a noise like a gunshot when the arc jumps the gap. You walk the route of the line (which you never know exactly because your drawings are always a little sketchy) and listen.

Usually this works. Not this time - it arced for a while, then somehow the 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 repaired the fault by sending a large EM pulse down the line knowing well that this would weld the two wires together therefore fixing the problem. That is the way I would write up the repair report.
  #23   Report Post  
Old January 2nd 16, 09:03 PM posted to sci.electronics.repair
external usenet poster
 
First recorded activity by DIYBanter: Mar 2007
Posts: 1,366
Default Diffferent techniques in troubleshooting

For me, it is purely a hobby, with the occasional household appliance or vehicular item intruding on occasion. So 'production' is not an issue, and unless 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 ST120 is a fool's game were it not a hobby. But, as therapy, and as a source of 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 polite society. No beancounters, no cost limits - a 'bulk' purchase might be 100 very common-value caps, or 20 common transistors, which might last a couple of years.

Peter Wieck
Melrose Park, PA
  #24   Report Post  
Old January 4th 16, 01:24 AM posted to sci.electronics.repair
external usenet poster
 
First recorded activity by DIYBanter: Mar 2009
Posts: 150
Default Diffferent techniques in troubleshooting

The st120 is an interesting beast. I did repair one in the 80's AFTER someone made swiss cheese out of it.
  #25   Report Post  
Old January 5th 16, 06:00 PM posted to sci.electronics.repair
external usenet poster
 
First recorded activity by DIYBanter: Mar 2007
Posts: 1,366
Default Diffferent techniques in troubleshooting

On Sunday, January 3, 2016 at 8:24:33 PM UTC-5, Ron D. wrote:
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


  #26   Report Post  
Old January 6th 16, 09:56 AM posted to sci.electronics.repair
external usenet poster
 
First recorded activity by DIYBanter: Aug 2010
Posts: 117
Default Diffferent techniques in troubleshooting

wrote in message
...
On Sunday, January 3, 2016 at 8:24:33 PM UTC-5, Ron D. wrote:
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.



Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
joinery techniques Electric Comet Woodworking 12 May 13th 15 06:29 PM
old techniques still in use? David Harmon Metalworking 0 May 1st 08 11:07 PM
old techniques still in use? Wes[_2_] Metalworking 1 May 1st 08 02:31 AM
old techniques still in use? Wes[_2_] Metalworking 0 April 30th 08 10:06 PM
Polishing techniques Frederic Elias Woodworking 3 April 30th 04 05:44 PM


All times are GMT +1. The time now is 08:53 AM.

Powered by vBulletin® Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
Copyright 2004-2019 DIYbanter.
The comments are property of their posters.
 

About Us

"It's about DIY & home improvement"

 

Copyright © 2017