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  1. #1
    Join Date
    Feb 2004
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    Troubleshooting Millivolt Circuits S/Pioneer

    Seattle Pioneer.........This is a followup from your old post (very old) that was recently resurrected and closed.

    You were making mention of a device you made for powering a millivolt system to test it. I purchased a meter around 1967-68-69 that did that very thing.
    Honeywell Systems Tester W720B1011. I hadn't even thought about it in 30 years, but I found it in my rollaway. Still working condition except the battery holder is damaged from leaving the batteries in. I don't think I ever used that function.

  2. #2
    Join Date
    Mar 2001
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    1,526

    Honeywell W 720 Systems Tester

    Ive got mine in the truck. Bought it back in 1969. You can get a new battery holder from Radio Shack. (don't ask how I know) Also have an Annie thermocouple -valve tester that has the same millivolt test feature as the W -720 I use them both a lot on stoves and commercial gas appliances. Guess I'll will them to my boys.
    One way to outthink people is to make them think you think. They'll think you're not really thinking what you're trying to get them to think you think...........

  3. #3
    Join Date
    Feb 2004
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    Quote Originally Posted by uniservice View Post
    Ive got mine in the truck. Bought it back in 1969. You can get a new battery holder from Radio Shack. (don't ask how I know) Also have an Annie thermocouple -valve tester that has the same millivolt test feature as the W -720 I use them both a lot on stoves and commercial gas appliances. Guess I'll will them to my boys.
    Too funny, and the beat goes on. Seems we just can't part with old cool tools.

  4. #4
    Join Date
    May 2004
    Location
    Sunny Mid South
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    I'll have to bid on them if I see them in the bottom of a box at an auction. Or buy them if I run across them otherwise....
    -Surf Life Hard!!!-

  5. #5
    Join Date
    Aug 2004
    Location
    S.E. Pa
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    6,292

    Smile

    I think this BASO kit might be the current version of what ya'll are looking for. You can do the same tests with any good meter that has millivolt and milliampere capability. The enclosure explains the various tests. There are several thermocouple interrupter blocks available to facilitate attaching leads to a TC for a closed reading. My current block is the TCA-1 adapter from Field Controls which I also use when I mount spill switches on water heaters and boilers that have a TC.

    HTH
    Attached Images Attached Images

  6. #6
    Join Date
    Feb 2004
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    2,474
    Yes it appears to have the same functions as my Honeywell, but I can't think of a situation where i ever considered using it.

  7. #7
    I'm not really trying to hijack this thread, but I have a question about a
    W720 that I'd like someone who is familiar with it to answer, and this
    seemed like the place to ask.

    I have a W720B1011 that was my Dad's. After repairing the damage from a pair
    of leaky alkaline batteries and replacing the dead fuse, I tested it out.
    When I plugged in into the 120VAC wall outlet using the 500VAC setting and the
    input jacks, it read about 170VAC (what I would expect for a peak reading).

    Please pardon my ignorance, but is this device intended to display peak
    voltages?

    I didn't find anything specific in the manual; however, the cover states that
    it is calibrated only for sine waves. To me this implies that the series
    resistance was chosen to scale the input by 1.414... to get a peak reading,
    but I'd like some confirmation.

    Thanks in advance.

  8. #8
    Join Date
    Mar 2001
    Posts
    1,526
    I think so,,,,,,,,,,,,,Never really paid attention to it in the A/C mode, just use it more for the millivolt and temperature features.
    One way to outthink people is to make them think you think. They'll think you're not really thinking what you're trying to get them to think you think...........

  9. #9
    Thanks for the quick response.
    Could I trouble you to try measuring a normal 120V outlet with yours?

    Thanks again

  10. #10
    Here is how to make your own tester. This is for techs who need a simple test rig for millivolt systems.You do not need more than 3 items to get it all done. One battery, 1.5 volt nominal, two matched resistors, or light bulbs with a matched resistance of 12 to 20 ohms each.
    Put one load on the hot generator and see if it is still producing 500 or more millivolts. Or use the battery and both resistors/bulbs in series. The voltage across just one of the resistors will be 750 mv. Use that to test the gas valve.

  11. #11
    Join Date
    Mar 2001
    Posts
    1,526
    Or find a W720 system tester in the bottom of a box at an auction.
    One way to outthink people is to make them think you think. They'll think you're not really thinking what you're trying to get them to think you think...........

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