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 Post subject: Triplett Tube Tester-HELP!!
PostPosted: Aug Mon 02, 2004 3:41 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 23
Location: Canada
I have a Triplett tube tester-model 3413-A. When I turn the line control the meter needle does not move but the light on the tube chart gets brighter. When I make the test on a tube the tube does light up but the needle still does not move. The adjustment on the meter does move the needle. I need a lot of help on this one. Thanks for your help. Moe


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 Post subject: Triplett Tube Tester-HELP!!
PostPosted: Aug Mon 02, 2004 4:16 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 31285
Location: Maryland 20709, USA
Hi Moe,<P>As with any piece of vintage equipment, this tester should be evaluated and repaired / restored as needed before you try to use it. Although tube testers have fewer components than radios, the ones which are there will still deteriorate over time.<P>------------------<BR>73 de Leigh W3NLB | | Leigh@AtwaterKent.Info<BR><A HREF="http://www.AtwaterKent.info" TARGET=_blank>http://www.AtwaterKent.info</A> | | <A HREF="http://www.Synchrophase.info" TARGET=_blank>http://www.Synchrophase.info</A>


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 Post subject: Triplett Tube Tester-HELP!!
PostPosted: Aug Mon 02, 2004 5:27 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 25381
Location: Pocasset, Cape Cod, MA
The common denominator seems to be the meter, though the problem could also be a switch not making contact. I would concentrate on the line-adjust circuit, which is pretty simple: a transformer winding feeding the rectifier and meter in series. I don't know if there is a line-adjust pot in series also but it could be open.<P>I'm guessing the circuit is the same as the Heath models.<P>------------------<BR>


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 Post subject: Triplett Tube Tester-HELP!!
PostPosted: Aug Mon 02, 2004 6:37 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 1770
Location: Warwick,RI
You say the "adjustment"on the meter does move the needle.Are you talking about the zero adjustment screw on the lower part of the meter cover that turns with a screwdriver blade?<BR>If so,will the pointer move smoothly away from and then back to zero?<BR>Normally,you adjust that screw by always moving it in a clockwise direction,and if the needle is not jammed,it should move away from and then back to zero as you turn the screw clockwise.<BR>Assuming the screw allows normal needle movement we then know that the meter movement has a reasonable degree of freedom to move on its bearings.<BR>Next step is to determine whether the meter movement may have an open coil.Disconnect the meter from the tube tester and connect it (the meter alone)to a VTVM or VOM ***with** a resistor in series.This resistor prevents damage to the meter movement coil.<BR>The value resistor to use depends on the full current rating of the meter movement in your tube tester,and can be calculated using ohm's law,or the lazy way is to start with a high value resistance....let us say...10,000 ohms or more and keep trying lower values of resistance(carefully!!) until you find the one that allows full scale(or almost full scale) needle movement on your tube tester meter.<BR>Such movement will prove the coil is not open,of course.<BR>Once the meter movement is thus cleared of suspicion you can concentrate your trouble shooting work on other areas of the tube tester.<BR>I am told that if you use a solid state DMM for the above test that you can dispense with the safety resistor mentioned above,but I do not know if every DMM is safe to use in that manner.(Without the resistor).<BR>Malcolm<P><BR>------------------<BR>


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 Post subject: Triplett Tube Tester-HELP!!
PostPosted: Aug Mon 02, 2004 8:28 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 634
Location: Scandia Minnesota U.S.A.
I often use my dirt cheap digital volt meter to check an analog meter. I find the 20K scale will deflect most meters about 14 scale. Good enough to say that the coil is ok.<BR>-Jeremy<BR>PS. If I want to be real cautious, I start out on the 2000K scale and work my way down.<P>------------------<BR>After working on computers all day long, its nice to turn on a 70 year old radio and have it work as good as the day it was made...


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 Post subject: Triplett Tube Tester-HELP!!
PostPosted: Aug Mon 02, 2004 8:39 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 828
Location: Grand Blanc, MI USA
Most of the advanced DMMs have autoranging on the ohms function. It's best to use a series resistor when testing an analog meter movement. Better safe than sorry.<P>------------------<BR>


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 Post subject: Triplett Tube Tester-HELP!!
PostPosted: Aug Mon 02, 2004 11:15 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 23
Location: Canada
I performed the test with a digital volt meter as tubesrgood and bestland suggested. The meter did not move at all. Maybe I did it correctly. Where do I go from here? Thanks, Moe


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 Post subject: Triplett Tube Tester-HELP!!
PostPosted: Aug Tue 03, 2004 12:24 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 634
Location: Scandia Minnesota U.S.A.
Did you get any reading on your digital meter Moe? If not, sounds like you have an open meter coil. If your patient, steady, and so inclined, you could open up the meter and see if you can spot the trouble. Otherwise, you may have to replace the meter.<BR>-Jeremy<BR>PS. Yes Chris, most of the advanced digital meters are auto-ranging. However, the dirt cheap ones you get for the hefty sum of $4 are the old "guess as you go" type. I use those a lot in my shop, as I dont care as much when I drop one on the floor.<P>------------------<BR>After working on computers all day long, its nice to turn on a 70 year old radio and have it work as good as the day it was made...


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 Post subject: Triplett Tube Tester-HELP!!
PostPosted: Aug Tue 03, 2004 2:53 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 828
Location: Grand Blanc, MI USA
On the meter thing--I used to have a Radio Shack DMM--their best one at the time (say 5 years ago). My compressor repair guy borrowed the thing and tried to measure some 460 volt three phase wiring to a motor. Don't know what he did--but the meter blew up in his hand. Thankfully he was not hurt--but I learned why they say that the RS meters are not for commercial use. No more of those kind of meters for me--I stick with the Fluke stuff. Not only can you drop the Fluke stuff on the floor, it is nearly indestructable electrically--and of course much safer than the cheap stuff. My needs are somewhat different than other people's, since I calibrate other gear with my meters. Still--I think a quality meter is a very sound investment. The Fluke meter will be more accurate, safer, and be worth something if you choose to sell it in the future. Plus--made in the USA.<P>I would use a $4 meter to measure low voltage stuff, or for the meter check we have been discussing. Would not want to measure 400 volts though. Modern electronic gear (that the cheap meters are probably geared towards) just does not operate at the same voltages as tube equipment.<P>------------------<BR>


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 Post subject: Triplett Tube Tester-HELP!!
PostPosted: Aug Tue 03, 2004 3:19 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 23
Location: Canada
Thanks for the information Jeremy. No-- there was no reading at all on the meter. Moe


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 Post subject: Triplett Tube Tester-HELP!!
PostPosted: Aug Tue 03, 2004 6:22 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 25381
Location: Pocasset, Cape Cod, MA
Open the meter and find out exactly where the break is. If it's the moving coil you're out of luck (well, I <I>have</I> fixed one in a Hickok but it's not easy) but it might be in a connection that you can get to.<P>------------------<BR>


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 Post subject: Triplett Tube Tester-HELP!!
PostPosted: Aug Tue 03, 2004 7:04 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 634
Location: Scandia Minnesota U.S.A.
Yeah Chris, I shudder to think of measuring the 1000 DC volts these cheapo meters are supposedly capable of. But, as I rebuild battery packs for a living, their most common measurement is 4.35 volts max. With that, I figure I'm ok. I can definetly appreciate the features of quality equipment like Fluke, but I just dont do the severe service that would require one on a regular basis. I have one stashed away for when I need it, but mostly abuse...i mean use...the cheap stuff.<BR>-Jeremy<P>------------------<BR>After working on computers all day long, its nice to turn on a 70 year old radio and have it work as good as the day it was made...


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