The Heathkit 102 QM-1 Q-meter is clearly nowhere near as accurate as a Boonton, but it a great beginners tool.

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I’ve found a better assembly and use manual:

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And this is some additional information:

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An EE friend talked me through restoring the QM-1. I replaced all the electrolytic capacitors, measured each resistor and changed all of them for newer metal film resistors. Most of the the carbon composition resistors had increased in value, putting them well out of tolerance, I removed the solder from some questionable connections, tested all the tubes, then put the voltage regular and applied power to the unit through a series 120 100W incandescent light bulb.

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The logic being any short would cause the bulb to glow brightly. My EE friend has a special test rig with an Edison light bulb socket, an AC input power switch, light bulb bypass switch, and a NEMA 15-5R power socket. He uses different wattage bulbs for different tests.

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I’m guessing all the calibration coils are 250uH with a Q of 110.

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On the VNA my calibration coil read 251.4 and the q was 108. Pretty good for a product older then I.

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At least I now have a nice variable RF oscillator that covers 150kHz to 18MHz, or 150kc to 18mc.

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The case was actually in much better shape then it initially looked. A lot of TLC by my artistic inclined wife and the unit looks pretty snazzy. She used home made soap, warm water, a soft brush, sponge, and a lot of care. I’m guessing here, but I suspect she spent 5 hours cleaning the case.

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The OD3 voltage regulator produced 153 volts, well within tolerance. All of the tubes (Valves to our British cousins) checked near perfect for emission.

We replaced the 2 conductor power cord and 2 prong power connector with a 3 conductor and a NEMA 15-5P 3 prong power connector and added an internal fuse for safety.

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It has been educational to wind coils using various winding schemes.

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My unit was compared to a VNA in the EE Instrumentation and measurement practical lab and, within its limits, it is within 10 to 20%.

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This is an overview of using a VNA.

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Note, I did not do the measurement! The TA in charge of the lab did that. They aren’t silly enough to let “sort of freshmen dilatants” touch the expensive test equipment.

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My next goal is to get matching knobs for the controls.

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We replaced the missing rubber feet with stick on plastic feet.

All in all this has been a great practical learning experience.

I think I've covered all the major points.

If I might ask a question, "Why the fascination and determination to make precision measurements of Q?"
Are y'all into radio?

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