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 Post subject: Hickok 799
PostPosted: May Fri 06, 2005 6:49 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 128
Location: Naples, Florida. U.S.A.
The test meter on my 799 goes up to 1000 mics. I have the Rapid Operating instructions which lists tubes and settings, for tubes that will test over 1000 mics. However there are not any notes or multiplier factors in the notations column to use to obtain a reading. Am I missing something or is there some formula to apply to the reading? Any info. or insight will be greatly appreciated. Thanks. Tim<P>------------------<BR>


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 Post subject: Hickok 799
PostPosted: May Fri 06, 2005 7:51 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 11454
Location: North of Mpls, Minnesota
I would suggest going to Bama <A HREF="http://bama.sbc.edu/" TARGET=_blank>http://bama.sbc.edu/</A> and downloading the manual. It will explain how to read the meter and test tubes. <P>The tester and tubes could be damaged if not set up correctly<P>Dave <P>------------------<BR>Intelligence is the ability to use your knowledge


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 Post subject: Hickok 799
PostPosted: May Fri 06, 2005 9:51 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 128
Location: Naples, Florida. U.S.A.
Thanks for the advice. Though the information on Bama does not address this issue. The data on Bama does not even include the "Rapid Operating Instructions." Best Regards. Tim<P>------------------<BR>


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 Post subject: Hickok 799
PostPosted: May Fri 06, 2005 11:02 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 17349
Location: Albuquerque, NM 87123
Timothy--<BR>Do a search for 'Hickok 799' on this forum and look under Alan Douglas's post. Some of the members who replied have the info you need and may share with you.<P>------------------<BR>


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 Post subject: Hickok 799
PostPosted: May Sat 07, 2005 2:49 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 446
Location: Winnipeg, Manitoba, CANADA
I might be missing something. I have the full operating instructions, and the Shunt control is supposed to take care of this somehow. The manual states;<BR>"Continuously variable, provides Gm range control; low, 1,000 to 5,000 micromhos,; high, 5,000 to 20,000 micromhos."<BR>Further in the manual, it states the Shunt control works with two Gm sensing resistors. How this is accomplished, I have no idea. But you do get really detailed calibrating instructions, if that could possibly compensate for not knowing how the heck the Gm range works. <P>------------------<BR>"You can lead a horticulture, but you can't make her think."


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 Post subject: Hickok 799
PostPosted: May Mon 09, 2005 7:04 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 128
Location: Naples, Florida. U.S.A.
Seems like there is some good information and ideas out there but I am wondering if anyone out there can actually inform me on the mystery of achieving gm readings on a 799? It is actually a nice tester, easy to set up and quite simple to service and calibrate. But I guess all that goes out the window if I do not know how to receive a proper gm reading. Best Regards to all. Tim<P>------------------<BR>


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 Post subject: Hickok 799
PostPosted: May Mon 09, 2005 2:45 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 30698
Location: Pocasset, Cape Cod, MA
I haven't looked at mine in a long time, but aren't there two different models of 799s? The push buttons have different functions.<P>------------------<BR>


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 Post subject: Hickok 799
PostPosted: May Mon 09, 2005 4:46 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 128
Location: Naples, Florida. U.S.A.
Yes, I believe you are correct. My serial number is 345 00574. The push buttons are as follows: P1 Lo GM, P2 Hi GM, P3 Rect.P4 OZ4, P5 Test, P6 D.T. However the meter still just goes to 1000 mics. Even with the "Rapid operating Instructions, when the unit is set to the proper settings for a tube, the meter still just pegs out if the tube is capable of reading over a 1000 mics. This particular unit is in outstanding condition but at this point is not of much value to me. Thanks. Tim<P>------------------<BR>


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 Post subject: Hickok 799
PostPosted: May Tue 10, 2005 1:33 am 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 575
Location: Stafford, Texas USA
Timothy<P>Were do you fine the” 1000 mics”? I do not have a good picture of the 799 meter.<BR>Yes, you are missing the notes or multiplier factors to use to obtain a reading. <P>Has Randy said:<P>It is the SHUNT CONTROL – Continuously variable, provides GM range control:<P>With P1 GM low, push it is 1,000 to 5,000 umhos.<P>With P2 GM HI, push it 5,000 to 20,000 umhos.<P>This is on page 5 of the manual.<P>Try testing a low mu tube 12AU7 and then a HI mu tube 12AT7.<P>If you have been using the right set up for the tubes that you have been testing.<P>An the GM test always pegs the meter if the tube is capable of reading over a 1,000 umhos. Then you have a problem in the GM test.<P>In the manual, see page 8 figure 4., of the simplified Mutual Conductance Test Circuit.<P>Something is bad in this circuit. <BR> <BR>Jimmie Stewart<BR><P>------------------<BR>


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 Post subject: Hickok 799
PostPosted: May Tue 10, 2005 4:39 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 575
Location: Stafford, Texas USA
Tim<P>Does the 799 test a rectifier tube like a 5Y3 ok? <P>Does the line test work ok?<P>If the two tests above work then it is most likely the GM circuit.<P>First I would change out all of the SS Diodes to new (made after 1995 less noise) 1N4007 Diodes. Check the two GM sensing resistors, the main thing here is that they match +/- 1% 163 163 is ok but 162 164 is not. Check the shunt control to be 3K at 3w. Replace the electrolytic capacitors.<P>The Parts have to be good before you can CAL the unit.<P>Jimmie Stewart<BR><P>------------------<BR>


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 Post subject: Hickok 799
PostPosted: May Tue 10, 2005 5:52 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 446
Location: Winnipeg, Manitoba, CANADA
Aaaaaaaaaaaaaah! Insert picture (and appropriate picture) of me smacking my forehead. P1 is the low gm range, and the full scale is 5,000 micromhos. P2 is the high gm range, and the full scale is 20,000 micromhos. The 1,000 scale (and the single scale is all you get) is a per centage; simply divide by 10 to get 100. <BR>I tested a few tubes on a 6000A and the 799. It makes sense now. <BR>However, I still haven't figured out the 'rapid' instructions, because I don't have them. But now I understand the 799 a lot more than I ever did. Not bad for a tester I bought maybe three years ago but never use. <P>------------------<BR>"You can lead a horticulture, but you can't make her think."


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 Post subject: Hickok 799
PostPosted: May Thu 12, 2005 1:52 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 128
Location: Naples, Florida. U.S.A.
Sorry folks, I hate to keep beating a dead horse, but does anyone have a Hickok 799 that uses it. I have been through the instructions time and time again and still can not figure out how to acquire an accurate gm reading. I will donate $50.00 to anyones favorite charity or to this site if someone can pound into my head, where I understand, on how to acquire a gm reading. I have been through my unit and internally it is fine. But there must be something I am missing because if I follow the tube setting data the readings are of no consequence if they go over 1000 mics. At the end of my rope. Help. Regards. Tim <P>------------------<BR>


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 Post subject: Hickok 799
PostPosted: May Thu 12, 2005 2:46 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 30698
Location: Pocasset, Cape Cod, MA
I may have some time this weekend, but between work, and two nights at Town Meeting, plus keeping up with caterpillars eating the trees, time is short.<P>------------------<BR>


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 Post subject: Hickok 799
PostPosted: May Thu 12, 2005 3:51 pm 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 128
Location: Naples, Florida. U.S.A.
Thanks Allen. Sorry to hear about those caterpillars though. Here in Florida we have the infamous palmetto bugs. A nice word for cock roaches I think. Regards. Tim<P>------------------<BR>


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 Post subject: Hickok 799
PostPosted: May Fri 13, 2005 6:20 am 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 575
Location: Stafford, Texas USA
Timothy <BR>You have to answer the ??? if we are going to help you. Plus you have to test the tester part by part to find out if you have a bad part or not. <BR> I think that if the GM test always pegs the meter if the tube is capable of reading over a 1,000 umhos. Then you have a problem in the GM test circuit.<BR>Lets find the bad part or not. Tube testers are FUN.<BR>1. What is a mics ? The term is micromhos or umhos.<P>2. The scale at the top of the meter is just a scale. Makes it easy to say, OK over 350.<P>3. What the tube that you are testing that below 1,000 mics.<P>4. Have you tested a good power rectifier tube? The best is a 5Y3, this is a emission test an takes the GM test circuit out of the picture. Test one now. Is it good or BAD, or pegs the meter?<P>5. What does this tell us?<BR> A. If the meter circuit is good and the shunt pot is good or bad. If the meter pegs on this test the shunt pot is most likely open and not shunting part of the current around the meter. On the other hand, a bad switch.<P>6. Have you tested a good single Triode tube? Some thing like a 6J5, 6C4, etc., one that use the P1 Low GM switch is better, this will take switch P6 out of the picture. The 799 test all tubes as triodes so the simpler the better. Test one now. Is it good or BAD, or pegs the meter? If you have a 6C4 set the color switch to green, Htr. to 6.3, Bias to 17, shunt to 0, socket 20, press P2. Is it good or BAD, or pegs the meter? <P>7. From the manual page 6 step 6.” Read Mutual conductance from the top colored scale, Red is faulty, yellow is ? quality and the green areas indicate acceptable quality. GM range control: With P1 GM low, push it is 1,000 to 5,000 umhos. With P2 GM HI, push it 5,000 to 20,000 umhos. This is on page 5 of the manual. What I cannot remember is if the umhos reading starts(1,000/5000) at the low end of the red part of the scale or at the low end of the green part of the scale. No problem all we need to know is that P1 full scale is 5,000 and P2 full scale is 20,000 umhos. <P>8. This is a good place to stop. Did the 6C4 peg the meter? Then the GM circuit is bad. In the manual, see page 8 figure 4., of the simplified Mutual Conductance Test Circuit. <BR>Something is bad in this circuit. On the other hand, a bad switch.<BR>Did the 6C4 read in the green, then the tester is working. <P><BR>Jimmie Stewart<BR><P>------------------<BR>


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 Post subject: Hickok 799
PostPosted: May Fri 13, 2005 10:26 pm 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 128
Location: Naples, Florida. U.S.A.
Hello Jimmie, I tested a known good 5Y3 and a 6J5, both tubes tested fine. I have been through this unit and all internals are up to spec. My point is if a tube let's say a 6550 is tested, it should test at least 7000. With the meter only going to 1000 it will peg the meter. How do I know where this tube is testing on the GM scale? Thanks. Tim <P>------------------<BR>


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 Post subject: Hickok 799
PostPosted: May Fri 13, 2005 10:48 pm 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 128
Location: Naples, Florida. U.S.A.
Jimmie, when I test a 6189 I get a reading of 920 and 920. The same tube tests 2300 and 2300 on my 752. Best regards. Tim<P>------------------<BR>


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 Post subject: Hickok 799
PostPosted: May Sat 14, 2005 12:45 am 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 11454
Location: North of Mpls, Minnesota
Tim<P>Post a picture of your meter, perhaps we can clear this up.<P>Dave<P>------------------<BR>Intelligence is the ability to use your knowledge


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 Post subject: Hickok 799
PostPosted: May Sat 14, 2005 4:26 am 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 128
Location: Naples, Florida. U.S.A.
I will see if I can borrow a digital camera and do so. Regards. Tim<P>------------------<BR>


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 Post subject: Hickok 799
PostPosted: May Sat 14, 2005 5:02 am 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 128
Location: Naples, Florida. U.S.A.
Well I was able to get a camera and the picture uploaded to test equipment but I'll be darned if I can get it to appear here. Regards. Tim<P>------------------<BR>


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