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Vintage Test Gear and Workshop Equipment For discussions about vintage test gear and workshop equipment such as coil winders. |
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4th Jun 2011, 3:49 am | #1 |
Retired Dormant Member
Join Date: Oct 2009
Location: Benalla, Victoria, Australia.
Posts: 5
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Advance T 2 Q Meter
Hoping that the forum members might be able to direct me to information or a manual for this unit. Can organize some photos of the internals if of any interest.
Ross |
4th Jun 2011, 1:23 pm | #2 |
Hexode
Join Date: Jul 2008
Location: Gateshead, Tyne & Wear, UK.
Posts: 336
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Re: Advance T 2 Q Meter
Hello Ross
I have been looking for a manual for my Advance T2A “Q Meter” but I have been unable to find anything. My unit had leaky electrolytic capacitors and a few high value resistors and now appears to work, but without the operating manual, I cannot say for sure. Please find attached a few pictures of my “Q Meter”. Regards Stan.
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4th Jun 2011, 5:54 pm | #3 |
Octode
Join Date: Oct 2007
Location: Exeter, Devon, UK.
Posts: 1,554
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Re: Advance T 2 Q Meter
You are in luck. I found an Advance catalogue specification dated 1970 for the T2A. It was not quoted in 1972, so had presumably been discontinued by then.
I then thought of a single sheet of unidentified circuit diagram lying in the bottom of my Advance manuals pile. Behold, it turns out to be the T1 circuit, dated 1956, with a date stamp for March 1966. So I suspect it will be very close indeed to the T2A version. Probably valve changes only. It is interesting that they used an inductance loop, across which it is easy to measure the input voltage, and tap off a fraction for the test. Marconi TF329 of 1945 used the small resistor method, which needs a thermocouple meter to measure the rf current through the small (20milliohm) resistor. And it is always the thermocouple which has burnt out. I attach the information I have and the circuit. Bill m0wpn |
4th Jun 2011, 8:50 pm | #4 |
Dekatron
Join Date: Jan 2004
Location: Newcastle upon Tyne, Tyne & Wear, UK.
Posts: 8,194
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Re: Advance T 2 Q Meter
Hi Gents, I have the T2 version and manual, slightly earlier and with a round meter, but circuit appears the same.
Main problem with mine were the small black Hunts caps gone leaky, and I think one high resistor. (replacement of these should not affect cal) I also have a set of standard coils so I was able to check my calibration. (If you send me a PM Stan, you can bring yours over to be checked and I'll show you how it operates. Ed |
4th Jun 2011, 9:29 pm | #5 |
Hexode
Join Date: Jul 2008
Location: Gateshead, Tyne & Wear, UK.
Posts: 336
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Re: Advance T 2 Q Meter
Hello Bill
Thank you for posting the information on the T2A Q Meter. Being a compulsive horder I rescued this instrument from a skip at work as it was marked unserviceable and set about repairing it. Although it was a long time ago, I remember replacing the electrolytic capacitors in the power supply and as Ed mentioned, a few old hunts capacitors and some high value carbon composition resistors on the small PCB. The oscillator is spot on frequency as compared to a Marconi 2019 signal generator, using a digital frequency counter. Now that I have the information, I have no excuse not to use the instrument. Many thanks Stan.
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5th Jun 2011, 12:55 am | #6 |
Retired Dormant Member
Join Date: Oct 2009
Location: Benalla, Victoria, Australia.
Posts: 5
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Re: Advance T 2 Q Meter
The catalogue sheet and circuit have gone a long way towards my understanding this piece of gear. Would be interested in clarifying the recommended uses of the "delta C"-(C17?) and "delta Q"-(R?) controls.
Impressed with the use of modulation to remove the necessity for dc amps and fragile thermocouple meters. Thanks for the assistance. Ross |
5th Jun 2011, 5:09 pm | #7 |
Octode
Join Date: Jan 2003
Location: Guildford, Surrey, UK.
Posts: 1,959
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Re: Advance T 2 Q Meter
Ross
If you want to compare a reference coil with a production sample, for example, you can use the delta C and delta Q controls to do this. Set up the reference coil at resonance at the desired frequency with the 'Capacitance' control, with the 'delta C' and 'delta Q' controls at zero. Adjust the Q meter reading to a convenient level with the 'Set Level' control and remember that level. Replace the reference coil with the production sample and use the 'delta C' control to return to resonance and the 'delta Q' control to make the meter reading the same as with the reference coil. The scale reading of 'delta C' is a measure of the difference in inductance between the reference and the sample and the scale reading of 'delta Q' indicates the difference in Q. I tried this with a couple of 10mH +/- 10% inductors and the delta C setting had to be altered to + 1.5pF at 200kHz for resonance, but the Q of each inductor measured the same, as the delta Q control did not need to be altered from its original position. Ron |
7th Jun 2011, 4:16 am | #8 |
Retired Dormant Member
Join Date: Oct 2009
Location: Benalla, Victoria, Australia.
Posts: 5
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Re: Advance T 2 Q Meter
Ron
That all makes sense. The T2 is opened up on my bench, time to check the Hunt caps and give everything a once over prior to turning it on. Again, thanks to all. Ross |
3rd May 2012, 7:38 pm | #9 |
Hexode
Join Date: Jul 2008
Location: Gateshead, Tyne & Wear, UK.
Posts: 336
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Re: Advance T 2 Q Meter
Hello Ross
I have found a copy of the "Advance Q Meter T2 Instruction Manual" with component list and circuit diagram. Please see attached PDF copy of the manual. I hope it is of some use to you and to other Q meter users. Regards Stan.
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4th May 2012, 11:29 am | #10 |
Retired Dormant Member
Join Date: Oct 2009
Location: Benalla, Victoria, Australia.
Posts: 5
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Re: Advance T 2 Q Meter
Hello Stan,
Many thanks. Having the manual ties up all my remaining loose ends. Regards Ross |