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City: Los Angeles
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Hmmm, Yes I thought of that.
I've been trying to just check the circuit at this point without letting out any magic smoke.
I have taken the line voltage up to 80 VAC which gives 96 or so on pin1.
These measurements are static as I removed the tube.
The other leg of the 95 VDC supply shows a reading of 10 VDC or so, so those resistors have an effect on the voltage.
I just now went back and re-measured with the tube installed.
I took it up to maybe 75 VDC, nothing.
I tried 80 VAC on the line again, and THIS time voltage on pin 1 went to 96 VDC, then began dropping after a moment.
Thanks!
It finally stabilized with 40 VDC on pin 1, -1 V on pin 2, 101 V on the supply.
Anyway, great breakthrough for me! Thanks so much!
I still don't know why I cant get more -V on the grid, the -1 VDC was obtained with the 37-100 mHz coil and the air cap all the way open.
Cleaning the old socket connections may help with that.
Again, thanks for your great advice!
Robert
Posts: 933
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City: Lansdale
State, Province, Country: PA
Well, I started back on this.. I am bound and determined to get this working..
If anyone has some pictures of the inside of this could you please send them to me to make sure I get the parts in the right places..
Thanks
More to follow..
Skip
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City: Lansdale
State, Province, Country: PA
Ok Back together.. Seems to work Well a Little bit.. It will Osc and put out frequencies.. Quite Stable
But When I turn the Sensitivity control all the way Clockwise I can only get it to Read Grid current About 1/2 way Between pegged to left and 0..
Voltages measured..
115 DC after Rectifier
110 DC After 1K ohm resistor
Pin1 of tube 81 Volts DC
Pin 2 of tube -15 Volts
Any clue why almost no grid current on meter??
Skip
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Do you mean pegged to the R.?
I guess you could measure the values of the 470K, the 10K sensitivity pot and 1K resistors leading to the meter.
The manual recommends checking solder connections of the coil socket, reflowing solder on the disk capacitors, and checking pins 1&2 for shorts.
I'm sure your pins aren't shorted, and if the resistors are in spec I guess you could re-flow the disk caps.
I still haven't fully re-assembled mine yet. I've had issues with the meter wiring breaking as I try to reassemble the unit.
I'll try some braided wire for it at some point when I have the time.
At least if you have some reading, you could still I.D. a "dip" if it doesn't 0 out and not rise again, right?
Hope it comes together for ya!
Posts: 933
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No I mean pegged to the left Below Zero.. The sensitivity control can only bring it back close to 0..
All resistors have been replaced the caps are disk so I haven't replaced them..
Skip
Posts: 933
Threads: 140
Joined: Mar 2015
City: Lansdale
State, Province, Country: PA
Ok, Fixed.. I went over it checking every connection and every wire.. I missed a connection..After putting wire where it was supposed to go I now have Grid current.. The OSC still works and is very Stable on counter.. Next to check to see if I can measure a circuit.. Have to make up a Resonant circuit..
So so far so good..
Skip
Posts: 1,475
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City: Kansas city, MO.
Been there also Skip. Missed a wire connection, connected wrong spot, or missed getting it soldered.
Glad you found it. 
Posts: 933
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Joined: Mar 2015
City: Lansdale
State, Province, Country: PA
Me too. I wasn't going to allow it to get the best of me. Now to see if it really works..
Skip
Posts: 933
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Joined: Mar 2015
City: Lansdale
State, Province, Country: PA
I was able to get a dip..Had a old coil and cap from a Heathkit SB-102 Radio.. Was able to adjust coil and see dip move in frequency.. So it works..
Now to put together in case and call it done..
Skip
Posts: 933
Threads: 140
Joined: Mar 2015
City: Lansdale
State, Province, Country: PA
Well I can get a dip.. Not very good and circuit has to be inside the antenna.. if put it close by nothing.. Any clue to what could be wrong?
I will take a picture of what I have to do to gt a dip..
Skip
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City: Menlo Park
State, Province, Country: CA
I'll have to dig mine out and have another play with it. Also, I have the instructions somewhere... these call out the best ways to couple to the circuit being tested.
Hold on, here's a link to instructions, in case you don't have them:
http://www.radiomanual.info/schemi/ACC_i...WA0KKE.pdf
If coupling is too close, the dip is rather broad in frequency, and of course this also affects the resonance of the circuit being tested to a greater extent. With less coupling, you should see weaker, but very sharp dips. The recommended procedure directs the user to start with strong coupling, and reduce it until the (subjective) sharp tuning of the dip is observed.
I was able to do this, setting up a short wave dipole, by adding a coupling coil at the receiver end of the coax feed. It had to be face on to the dip meter's coil at first, before I could figure out what was going on, then I could adjust and play with the proximity, once I knew I was looking at the correct dip.
It was fun to use though, and I did get a good antenna set up in the end.
Cheers
Ed
I don't hold with furniture that talks.
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City: Los Angeles
State, Province, Country: CA
Well, I finally have mine working also.
There are some good vids on youtube demo'ing it's use.
Much more versatile than I thought.
Posts: 1,287
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Joined: Nov 2017
City: Menlo Park
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Yes - they are really useful. One thing I'd like to do is make up coils useful for lower frequencies such as the ranges needed for broadcast band.
Good to hear you got yours working!
I don't hold with furniture that talks.
Posts: 933
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Joined: Mar 2015
City: Lansdale
State, Province, Country: PA
Well, I kind of gave up on mine right now To many other projects ..
Skip
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