Date   

Re: TEK 544

Ed Breya
 

I think I sent you an email - or maybe not. I can't tell with this system

 

Ed


Re: OT: X-band doppler water leak detection

stefan_trethan
 

I think the compressed air / leak detector method is most promising, and least damaging so definitely worth a try in any case. You might be able to hear the leak without a detector if you are very lucky, and it costs nothing.


Personally I doubt the thermal camera method will work unless the leak is massive. A few drops percolating through building materials will quickly take on the surrounding temperature and not show up on camera.


Most likely you will have to rip out a larger section anyway, if the materials are soaked, to repair the damage and prevent any mould issues.


ST


On Sat, Feb 22, 2014 at 5:12 PM, Albert LaFrance <albert.lafrance@...> wrote:


Here’s what you *really* need – technology from Atomic Age:

http://coldwar-c4i.net/EE0952/812.html

 

Albert

 



Re: Tek 465b - LV supply problem

 

I took a careful look at that part of the circuit earlier to figure out what it
does and how it works.

VR4326 sets the junction of R4326 and RR4316 to 20 volts above the +55 volt
output; R4326 and VR4326 can be considered a shunt regulator. That allows a
constant current of about 0.984 milliamps to flow through R4316 no matter how
the +55 volt output varies. U4411A sinks part of that current and the rest
drives Q4302 which drives the output transistor Q4301. The current combined
with VR4304 creates a level shift so the +15 volt output of U4411A can drive the
+57.3 volt input to the driver transistor while staying within the output range
of the operational amplifier.

U4411A can safely sink up to 5 milliamps so that current is well within its
capabilities. When I have designed similar circuits, I used a transistor in
place of CR4406 to unload the output of the operational amplifier.

If the output was out of regulation for any reason, then the voltages at pins 2
and 3 of the operational amplifier would differ by more than its small offset
voltage, up to about 5 millivolts, and the output of the operation amplifier
would go to either +20 or +2 volts depending on its output load.

Warm up for this circuit should take milliseconds.

On Sat, 22 Feb 2014 16:59:50 +0100, you wrote:

OK will check soon, but there is one more what I check: voltage on R4326/R4316 is first +83V and then slowly droping to +75V when +55V is back fo limit. If I not touch U4411 after 1 minute warm up +55V is OK.


Re: TDS 540 experts

Andy
 


Re: OT: X-band doppler water leak detection

Albert LaFrance
 

Here’s what you *really* need – technology from Atomic Age:

http://coldwar-c4i.net/EE0952/812.html

 

Albert

 

 

From: TekScopes@... [mailto:TekScopes@...] On Behalf Of edbreya@...
Sent: Friday, February 21, 2014 7:29 PM
To: TekScopes@...
Subject: [TekScopes] OT: X-band doppler water leak detection

 

 

We just acquired a property that has a house with radiant hydronic heating, and there is a leak in the PEX tubing somewhere in one of the upper floor heating zones. The water ultimately drips out through an opening in the ceiling of the lower floor. I don't want to tear up too much drywall or flooring to locate the actual leak point, which could be a few feet away in any direction. Before resorting to that, I figured I'd try an experimental setup with an old Solfan microwave doppler motion detector module.

 

I have collected a number of these over the years, so that's covered, and all I need is to set up power and an audio amp to listen in on the signals from the detector. I had planned on making a rig like this years ago, for locating a yellow jacket nest somwhere in a wall, but they wisely departed, causing the project to be mothballed. In that case, the sound would have been from body motion and wings buzzing, and easily audible, but for a water leak, it will depend on whether there's gurgling, spraying, or dripping action to get an audible signal.

 

Before I get started, I figured I'd check here to see if anyone has experimented with this stuff for this sort of pupose, or knows of commercial equipment that I could get ideas from. The Solfans run around 10.5 GHz, with Po maybe 10-40 mW, and normally rely on water absorption and motion of bodies up to a few meters away to provide an AC doppler signal. The detectors are DC coupled, so can in fact reach way down in frequency and even indicate position/phase of an object close to the horn - but not with high stability.

 

In this case the desired target is small streams or dripping water at maybe 0.1 to 0.5 GPM, from a distance of up to around a couple of feet, through layers of material depending on the view. From below, looking through the ceiling, there's 1/2" hydrated gypsum drywall, then about a foot (2x12" floor joists) of hollow space and possibly some fiberglas insulation, then 3/4" plywood subfloor, then the hollow PEX cavities formed with 3/4" x (3-6" W?) lathe strips. From above, there's 3/4" hardwood flooring, mounted on a 3/4" plywood substrate that rests on the lathe. The water loop is 1/2" PEX in a serpentine pattern, laid between the interdigitated lathe strips. Normal system pressure is about 15 PSIG. The objective is to locate the point of the leak in the tubing, as close as possible, and quickly, to minimize excess water damage. I think the water will be easiest to detect from below, and more accurately located from above, once the approximate location is narrowed down.

 

So, does anyone have any info, knowledge, or experience in this, or is there a better way? I know that there are ultrasonic leak detectors for gases, so I could rig up the loop to be tested with air instead, but then the ultrasonic emissions would have to be detected through layers of wood either way.

 

Ed


Re: Tek 465b - LV supply problem

Jacek
 

OK will check soon, but there is one more what I check: voltage on R4326/R4316 is first +83V and then slowly droping to +75V when +55V is back fo limit. If I not touch U4411 after 1 minute warm up +55V is OK.


Dnia 22 lutego 2014 16:18 David napisał(a):

 

The problem here is that the regulator is working properly which means any
errors caused outside of the feedback loop will be compensated for. There are
four possibilities:

1. Reference CR4421 could be bad.
2. U4411A could have a large input offset voltage.
3. The feedback loop divider made up of R4305, R4318, and R4406 could be bad.
4. There could be a high frequency oscillation which is not apparent.

Since you have eliminated the first three I would go back and make those
measurements (at least the first two) again *while* monitoring the output to see
if it shifts during any of the measurements. If there is an oscillation that
could be difficult to find. An oscilloscope with a x10 probe set to AC coupling
might reveal something at the base or collector of Q4301.

Check that the wiper of R4318 is the same voltage as the cathode of VR4421.

Something else I would try is removing Q4303 which will disable the current
limit.

I would also check zener diodes VR4304 and VR4326 as well as the forward voltage
drop of the other diodes and all of the transistor junctions.

On Sat, 22 Feb 2014 12:32:25 +0100, you wrote:

>Voltage divider is OK & working well ( +55V is changed when  R 4318 moved).
> To clarify: +55V is out of limit ( up to +63V ) when I start scope after hour of rest & is back to normal ( +55 ) when I am making a measurement of U 4411 ?! To make a good test when +55V is out of limit is not much time, but I find that on pin 1 of U4411 is +23V instead +15V. Maybe something wrong with C4306 - is leaking? When +55V is OK on pin 1 U4411 is +13,3V only.
>Dnia 20 lutego 2014 21:40 David napisa?(a):

> If pin 2 and pin 3 are that close, then the regulator is functioning properly
>and the place to look for a problem is the voltage divider made up of R4305,
>R4318, and R4406. Incidentally this is a measurement where a 4 digit meter
>would be handy to gain millivolt precision. You could also make this
>measurement directly between the pins instead of from each pin to ground. I
>usually do both to make sure they agree.
>If the output of the operational amplifier at pin 1 or the regulator output was
>being forced high or low, then the voltages at pins 2 and 3 would not be close.
>Leakage through capacitor C4305 would *lower* the output voltage so the
>capacitor cannot be the problem.
>R4406 could have drifted high or maybe the wiper of R4318 is not making good
>contact. I would certainly adjust R4318 through its full range a couple of
>times while measuring the +55 volt output to see what happens.
>The wiper problem is interesting in this case because the 1458 operational
>amplifier they used has a negative bias current (the inputs get pulled to the
>negative supply with a current of up to 0.5 microamps which would have the
>effect of raising the output voltage if the wiper of the potentiometer had
>enough series resistance. You could drop an LM358 operational amplifier which
>has the opposite bias current in place of U4411 to see if it changes the +55
>volt output from being high to being low to test this.
>On Thu, 20 Feb 2014 20:47:52 +0100, you wrote:
>>After measuements :
>>VR4421 +9,04V
>>U4411  pin 2 +9,04V, pin 3 +9,03V ( but pin 1 +13,4V instead +15V as stated on scheme ),
>>just for testing I exchange U4411 with  U4206  and result is same (voltage on  pins 1,2 & 3 ).
>>Mean time i find mistake with exchange  filter cap's - there was 500uF instead 1200uF on +55V filter - will observ if this will solve  behaviour of +55V supply. Ripple on +110 is 20 mV now 





--
Pozdrawiam, Jacek.


Re: Tek 465b - LV supply problem

 

The problem here is that the regulator is working properly which means any
errors caused outside of the feedback loop will be compensated for. There are
four possibilities:

1. Reference CR4421 could be bad.
2. U4411A could have a large input offset voltage.
3. The feedback loop divider made up of R4305, R4318, and R4406 could be bad.
4. There could be a high frequency oscillation which is not apparent.

Since you have eliminated the first three I would go back and make those
measurements (at least the first two) again *while* monitoring the output to see
if it shifts during any of the measurements. If there is an oscillation that
could be difficult to find. An oscilloscope with a x10 probe set to AC coupling
might reveal something at the base or collector of Q4301.

Check that the wiper of R4318 is the same voltage as the cathode of VR4421.

Something else I would try is removing Q4303 which will disable the current
limit.

I would also check zener diodes VR4304 and VR4326 as well as the forward voltage
drop of the other diodes and all of the transistor junctions.

On Sat, 22 Feb 2014 12:32:25 +0100, you wrote:

Voltage divider is OK &amp; working well ( +55V is changed when  R 4318 moved).
 To clarify: +55V is out of limit ( up to +63V ) when I start scope after hour of rest &amp; is back to normal ( +55 ) when I am making a measurement of U 4411 ?! To make a good test when +55V is out of limit is not much time, but I find that on pin 1 of U4411 is +23V instead +15V. Maybe something wrong with C4306 - is leaking? When +55V is OK on pin 1 U4411 is +13,3V only.
Dnia 20 lutego 2014 21:40 David <davidwhess@gmail.com> napisa?(a):
 If pin 2 and pin 3 are that close, then the regulator is functioning properly
and the place to look for a problem is the voltage divider made up of R4305,
R4318, and R4406. Incidentally this is a measurement where a 4 digit meter
would be handy to gain millivolt precision. You could also make this
measurement directly between the pins instead of from each pin to ground. I
usually do both to make sure they agree.
If the output of the operational amplifier at pin 1 or the regulator output was
being forced high or low, then the voltages at pins 2 and 3 would not be close.
Leakage through capacitor C4305 would *lower* the output voltage so the
capacitor cannot be the problem.
R4406 could have drifted high or maybe the wiper of R4318 is not making good
contact. I would certainly adjust R4318 through its full range a couple of
times while measuring the +55 volt output to see what happens.
The wiper problem is interesting in this case because the 1458 operational
amplifier they used has a negative bias current (the inputs get pulled to the
negative supply with a current of up to 0.5 microamps which would have the
effect of raising the output voltage if the wiper of the potentiometer had
enough series resistance. You could drop an LM358 operational amplifier which
has the opposite bias current in place of U4411 to see if it changes the +55
volt output from being high to being low to test this.
On Thu, 20 Feb 2014 20:47:52 +0100, you wrote:
After measuements :
VR4421 +9,04V
U4411  pin 2 +9,04V, pin 3 +9,03V ( but pin 1 +13,4V instead +15V as stated on scheme ),
just for testing I exchange U4411 with  U4206  and result is same (voltage on  pins 1,2 &amp; 3 ).
Mean time i find mistake with exchange  filter cap's - there was 500uF instead 1200uF on +55V filter - will observ if this will solve  behaviour of +55V supply. Ripple on +110 is 20 mV now


Re: No trace on 2215

odenman9
 

Hi,
I am sitting with the same problem a couple of years later. Did you ever find a solution. I suspect Q630A or Q631 to be faulty. It is very hard work to be able to desolder these components and check because the board is nearly inaccessible. It is really not at all like  the old service friendly Tek scopes.
Lennart


Re: TDS 540 experts

alberto.vaudagna
 

Idt7164S302O

Il 22/feb/2014 08:22 "Michael A. Terrell" <mike.terrell@...> ha scritto:
 

Alberto Vaudagna wrote:
> ya I saw them on fixed interval.
> The problem is that I cannot find the replacement IC.

What is the IC part number?


Re: Tek 465b - LV supply problem

Jacek
 

Voltage divider is OK & working well ( +55V is changed when  R 4318 moved).

 To clarify: +55V is out of limit ( up to +63V ) when I start scope after hour of rest & is back to normal ( +55 ) when I am making a measurement of U 4411 ?! To make a good test when +55V is out of limit is not much time, but I find that on pin 1 of U4411 is +23V instead +15V. Maybe something wrong with C4306 - is leaking? When +55V is OK on pin 1 U4411 is +13,3V only.




Dnia 20 lutego 2014 21:40 David napisał(a):

 

If pin 2 and pin 3 are that close, then the regulator is functioning properly
and the place to look for a problem is the voltage divider made up of R4305,
R4318, and R4406. Incidentally this is a measurement where a 4 digit meter
would be handy to gain millivolt precision. You could also make this
measurement directly between the pins instead of from each pin to ground. I
usually do both to make sure they agree.

If the output of the operational amplifier at pin 1 or the regulator output was
being forced high or low, then the voltages at pins 2 and 3 would not be close.

Leakage through capacitor C4305 would *lower* the output voltage so the
capacitor cannot be the problem.

R4406 could have drifted high or maybe the wiper of R4318 is not making good
contact. I would certainly adjust R4318 through its full range a couple of
times while measuring the +55 volt output to see what happens.

The wiper problem is interesting in this case because the 1458 operational
amplifier they used has a negative bias current (the inputs get pulled to the
negative supply with a current of up to 0.5 microamps which would have the
effect of raising the output voltage if the wiper of the potentiometer had
enough series resistance. You could drop an LM358 operational amplifier which
has the opposite bias current in place of U4411 to see if it changes the +55
volt output from being high to being low to test this.

On Thu, 20 Feb 2014 20:47:52 +0100, you wrote:

>After measuements :
>VR4421 +9,04V
>U4411  pin 2 +9,04V, pin 3 +9,03V ( but pin 1 +13,4V instead +15V as stated on scheme ),
>just for testing I exchange U4411 with  U4206  and result is same (voltage on  pins 1,2 & 3 ).
>Mean time i find mistake with exchange  filter cap's - there was 500uF instead 1200uF on +55V filter - will observ if this will solve  behaviour of +55V supply. Ripple on +110 is 20 mV now 





--
Pozdrawiam, Jacek.


Re: TDS 540 experts

Michael A. Terrell
 

Alberto Vaudagna wrote:
ya I saw them on fixed interval.
The problem is that I cannot find the replacement IC.
What is the IC part number?


Re: TEK 544

demianm_1
 

e-mail me at dmartin@.... You are right about the less useful new Yahoo Groups interface.


Re: OT: X-band doppler water leak detection

snapdiode
 

Unless you get one of those coherent fiber cameras, the image quality is abysmal.


Re: OT: X-band doppler water leak detection

Peter Gottlieb <hpnpilot@...>
 

Why not drill small holes and use one of those inspection cameras on a flexible gooseneck to look in the ceiling? Start where the water is showing and work from there.


Re: OT: X-band doppler water leak detection

Ralph Hartwell <ralph_yg@...>
 

Thermal imager and hot or cold water.
Not bad! That might just work.

True story: Many years ago I had a water leak from a hot water pipe that passed under a concrete floor - but where was it? Not having a thermal imager, I resorted to taking a wet mop and quickly swabbed the floor with warm water. Then I stood back and waited for the floor to dry. As it began to dry up, I marked the center of the first spot that became dry. Several iterations of mopping and waiting gave me a smaller diameter marker point. Cutting through the concrete showed that I was right on target, and the pipe was repaired without extensive digging and expensive concrete work.

As for the microwave detector, that might just work. I would use a DC coupled oscilloscope so I could watch for very small signals.

I have a similar X-band system that is easily able to measure reflected signals from raindrops as they fall outside of my workshop window. I have also used both C-band and KU-band satellite LNB's for detection of microwave noise signals from ionized gasses in discharge tubes and fluorescent lamps from as far away as 15 feet. Nothing more sensitive than a standard installers signal meter was required. I usually use my Tek scope to look at the low frequency signals.

Best DX & 73,

Ralph W5JGV - WD2XSH/7


Re: 2246 mod A power supply replacement capacitors advice

nielsentelecom@sbcglobal.net
 

Tom, thanks for the reply. I was going to calibrate the scope, so the first step was to check those voltages before I started. I found my voltages would not be in spec no matter how I just the potentiometer. That's how I got started. So far most of the caps in the secondary side are bad. Very few of them were good. Right now I have just assembled my oscilloscope, and I'm getting ready to test my voltages with both all boards loading the power supply. I have temporarily replaced all the caps in the secondary side except for the two high-voltage caps for the 59 V, and the 130 V. They tested good. My voltages are very close now. Using my load bank that I created. Nielsentelecom


Re: OT: X-band doppler water leak detection

Don Black <donald_black@...>
 

How about listening to the ceiling with a stethoscope. Since the object is to locate the leak you might hear the water dripping.

Don Black.

On 22-Feb-14 12:49 PM, KeepIt SimpleStupid wrote:
 
Ed:

All I can offer is the existance of GPR or Ground Pentrating Radar.  See: http://en.wikipedia.org/wiki/Ground-penetrating_radar  I would suppose that those services could be purchased.  Aparently, from what I read the harder part is interpretation of the data collected.

Ferrofluid - http://en.wikipedia.org/wiki/Ferrofluid  I have no idea.

Thermal imager and hot or cold water.

Just ideas.

 
So, does anyone have any info, knowledge, or experience in this, or is there a better way? I know that there are ultrasonic leak detectors for gases, so I could rig up the loop to be tested with air instead, but then the ultrasonic emissions would have to be detected through layers of wood either way.
Ed






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Re: OT: X-band doppler water leak detection

Dave Daniel
 

In my experience, the PEX pipe used in in-floor hydronic heating systems is intimately close to the special concrete in which the pipe is embedded. I would guess that there is little or no turbulence associated with the leak, which means that detection by acoustic means won't work.

The thermal imager idea is a good one. One possible source of a good thermal imager is your local fire district - if you can convince them to lend you a firefighter and their imager, you may be able to locate the leak. The floor covering would probably have to be something that conducts heat well, though - if the floor is carpeted, thermal imaging probably wouldn't work.

DaveD

On 2/21/2014 6:49 PM, KeepIt SimpleStupid wrote:
 
Ed:

All I can offer is the existance of GPR or Ground Pentrating Radar.  See: http://en.wikipedia.org/wiki/Ground-penetrating_radar  I would suppose that those services could be purchased.  Aparently, from what I read the harder part is interpretation of the data collected.

Ferrofluid - http://en.wikipedia.org/wiki/Ferrofluid  I have no idea.

Thermal imager and hot or cold water.

Just ideas.

 
So, does anyone have any info, knowledge, or experience in this, or is there a better way? I know that there are ultrasonic leak detectors for gases, so I could rig up the loop to be tested with air instead, but then the ultrasonic emissions would have to be detected through layers of wood either way.
Ed




Re: OT: X-band doppler water leak detection

KeepIt SimpleStupid
 

Ed:

All I can offer is the existance of GPR or Ground Pentrating Radar.  See: http://en.wikipedia.org/wiki/Ground-penetrating_radar  I would suppose that those services could be purchased.  Aparently, from what I read the harder part is interpretation of the data collected.

Ferrofluid - http://en.wikipedia.org/wiki/Ferrofluid  I have no idea.

Thermal imager and hot or cold water.

Just ideas.

 
So, does anyone have any info, knowledge, or experience in this, or is there a better way? I know that there are ultrasonic leak detectors for gases, so I could rig up the loop to be tested with air instead, but then the ultrasonic emissions would have to be detected through layers of wood either way.
Ed



OT: X-band doppler water leak detection

Ed Breya
 

We just acquired a property that has a house with radiant hydronic heating, and there is a leak in the PEX tubing somewhere in one of the upper floor heating zones. The water ultimately drips out through an opening in the ceiling of the lower floor. I don't want to tear up too much drywall or flooring to locate the actual leak point, which could be a few feet away in any direction. Before resorting to that, I figured I'd try an experimental setup with an old Solfan microwave doppler motion detector module.

 

I have collected a number of these over the years, so that's covered, and all I need is to set up power and an audio amp to listen in on the signals from the detector. I had planned on making a rig like this years ago, for locating a yellow jacket nest somwhere in a wall, but they wisely departed, causing the project to be mothballed. In that case, the sound would have been from body motion and wings buzzing, and easily audible, but for a water leak, it will depend on whether there's gurgling, spraying, or dripping action to get an audible signal.

 

Before I get started, I figured I'd check here to see if anyone has experimented with this stuff for this sort of pupose, or knows of commercial equipment that I could get ideas from. The Solfans run around 10.5 GHz, with Po maybe 10-40 mW, and normally rely on water absorption and motion of bodies up to a few meters away to provide an AC doppler signal. The detectors are DC coupled, so can in fact reach way down in frequency and even indicate position/phase of an object close to the horn - but not with high stability.

 

In this case the desired target is small streams or dripping water at maybe 0.1 to 0.5 GPM, from a distance of up to around a couple of feet, through layers of material depending on the view. From below, looking through the ceiling, there's 1/2" hydrated gypsum drywall, then about a foot (2x12" floor joists) of hollow space and possibly some fiberglas insulation, then 3/4" plywood subfloor, then the hollow PEX cavities formed with 3/4" x (3-6" W?) lathe strips. From above, there's 3/4" hardwood flooring, mounted on a 3/4" plywood substrate that rests on the lathe. The water loop is 1/2" PEX in a serpentine pattern, laid between the interdigitated lathe strips. Normal system pressure is about 15 PSIG. The objective is to locate the point of the leak in the tubing, as close as possible, and quickly, to minimize excess water damage. I think the water will be easiest to detect from below, and more accurately located from above, once the approximate location is narrowed down.

 

So, does anyone have any info, knowledge, or experience in this, or is there a better way? I know that there are ultrasonic leak detectors for gases, so I could rig up the loop to be tested with air instead, but then the ultrasonic emissions would have to be detected through layers of wood either way.

 

Ed

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