new here, need guidance

Discussion in 'General Electronics Chat' started by 1idejim, Feb 23, 2010.

  1. 1idejim

    Thread Starter New Member

    Feb 23, 2010
    14
    0
    hi guys, new here;

    i don't have a techno. background and need some advice.

    i locate irrigation valves with an electronic valve locator, 1748hz and would like advice on the systems upkeep.

    thi machine nulls over the wire path [earth ground] and when connected in a closed circuit it detects peak over the valve solenoid. i also have a peak only locator for wire paths, it however works on a different freq. that i don't remember right off.

    i would like to build a machine that would combine the two machines freqs. and operating characteristics.

    i also see a need in my business to be able to diagnoise my equipment and do minor repairs

    any direction would be helpful

    jim
     
  2. Mike33

    AAC Fanatic!

    Feb 4, 2005
    349
    25
    Well, that's a pretty tall order, Jim!

    I'd say step 1 would be to get some electronics background. Without it, you won't be able to combine the 2 pcs. of equipment, not ever! You'd have to understand how it works in order to modify it - there will be adjustments and so on that you'd need an understanding to perform if you were to build new/modify your stuff.

    Step 2 might be to try to find a schematic of the device(s) you have questions about, and post a link to them on here so we can take a look. Even a photo or 2. That will get you some answers about how to clean and maintain the things and keep them running well. THAT I believe you could tackle without a techno background!
    Good luck.

    ~Mike
     
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  3. loosewire

    AAC Fanatic!

    Apr 25, 2008
    1,584
    435
    Irrigation is a world wide thing,you will find that most large
    companies have very good equipment,you may find what
    you are wanting to do exist already. Even the best on the forum
    for company secrects reasons would not attemp to combine
    working instruments. As a person works on a job he learns
    things that help make work easier,maybe some one can help
    you make home made locator, a lot of smart people will look over
    post. Under ground locating can be a very sensitive subject also,
    so every one will take that into consideration also.
     
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  4. 1idejim

    Thread Starter New Member

    Feb 23, 2010
    14
    0
    i wrote both of you fine gentlemen a long and sincere reply earlier and it was erased during spell check.

    mr loosewire, i'm an accomplished locator, i consult and contribute on three forums concerning leak detection and locating.

    i agree with both of you, i need to learn the basics.

    i have 2 hand held TDR's one took a low voltage charge of 40mA and will no longer read distance only reading out of range which must be relatiing to an open circuit.

    i wll take pics and post them in this thread, if you would be kind enough to guide me through testing and possible repair i would be greatful.

    in reference to my op i discussed my idea with the manufacture of my locator, e-mailed a formal request to their R&D head and we'll see what the numbers say

    thanks again

    jim
     
  5. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Hello Jim,

    Please put your general location in your profile. You do not have to be exact; just a general location. This will actually help us to help you, as otherwise we have little clue as to what parts you might have access to.
     
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  6. 1idejim

    Thread Starter New Member

    Feb 23, 2010
    14
    0
    will comply, thks
     
  7. 1idejim

    Thread Starter New Member

    Feb 23, 2010
    14
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    when i get home tonight i'll post pics of the TDR, thanks
     
  8. Mike33

    AAC Fanatic!

    Feb 4, 2005
    349
    25
    Sure Jim, I work outside, too, and understand what a bonus learning to service your own stuff can be!
    Hope nothing got fried...maybe the manuf. will answer you and get you some troubleshooting data...
     
  9. 1idejim

    Thread Starter New Member

    Feb 23, 2010
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    0
    here's the pics. i was testing a 2 wire irrigation line, the 40mA is what the mfg specs as the decoder signal.....the use of TDR is very new to irrigation trouleshooting as a tech tool. i'm the only person using it full time.
     
  10. SgtWookie

    Expert

    Jul 17, 2007
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    Hard to tell from those photos (they're really dark and kind of fuzzy) but it looks like the uC (microcontroller is a PIC16F873?A (can't read the last digit)...

    In the 2nd pic, there is a 4.0MHz crystal (labeled X1) in a silver can, and a green disc cap on either side of it. It looks like the one on the right is broken (the left lead may be disconnected from the board). This means that the uC's clock input will not be correct, or non-existent.

    Try taking photos under better lighting conditions. Outside on a cloudy day is perfect; the lighting is very diffused, so the subject is very evenly illuminated with no harsh shadows. If there are no clouds, try draping a white sheet over yourself and the board; the cloth will make the light more diffused.
     
  11. 1idejim

    Thread Starter New Member

    Feb 23, 2010
    14
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    i'm trying to find out what i should be looking for when and how i should be testing this tool?

    any help would be kind.
     
  12. SgtWookie

    Expert

    Jul 17, 2007
    22,182
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    Are you finding the TDR helpful?

    You know how it works, right?

    The instrument sends a pulse down the wire. If there is a change in impedance along the wire, you will see a reflected bump or dip in the signal level that corresponds to the distance from the instrument to the anomaly.

    After looking at that 2nd photo again, I can see that the device has an EL2150 opamp near the BNC port, which is a very fast 125MHz bandwidth opamp with 100mA source/sink capability.
     
  13. 1idejim

    Thread Starter New Member

    Feb 23, 2010
    14
    0
    actually i've brought the TDR from the communication industry and introduced it to the irrigation industry.

    it took many years of testing and daily use to develope a system that is reliable enough to use in the location of missing underground solenoid operated irrigation valves.

    i am able to create a map of the buried valves by the readings i take at the controllers and use them in the field, reducing the amount of time it takes to locate lost valves by 50+%.

    i'm also able to check the condition of the field wiring and the solenoid condition without multimeters and am able to pinpoint the location of ground faults, again reducing the time spent and increasing the accuracy of the locates.

    the TDR pictured was fried by a low voltage mains connection, purely accidental.....if i am able to test the instrument i believe that i'll learn more about the machine it'self and maybe if i can repair the TDR i'll know even more.

    i've already purchased another TDR and use it daily.

    hopefully an interested party will help guide me through testing and repair

    thanks
     
  14. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Well, it's going to be mighty difficult if you don't plan on posting better photos than the first batch.

    I could just barely make out some of the part numbers. The photos are dark and the middle one slightly blurred (moved when shutter snapped). Having better photos of both sides of the board would help a great deal.
     
  15. 1idejim

    Thread Starter New Member

    Feb 23, 2010
    14
    0
    thanks, i'll supply anything i can to help.

    i have a fluke 87rms, a fluke 5/600 and a greenlee D20 multimeters. will there be anything else that i might need, do i need an analog multimeter?

    i'm greatful for your help

    jim
     
  16. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Some nice, clear photos of both sides of the board and the display would be a good start.
     
  17. 1idejim

    Thread Starter New Member

    Feb 23, 2010
    14
    0
    asap, i don't have the unit with me today.

    thank you
     
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