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Pete, I'd love to see a circuit or article on this. Donald KX8K

I agree. With an isolation xfmr, a GFI can only detect a *double* fault: The xfmr is not actually isolating, AND you also have an unplanned path to Ground. It's a little hard to imagine how that would

I guess you'll also wear thick rubber gloves and welding goggles to compliment your ultra-safe approach. ;-) If you're going to be using an isolation transformer, that GFI will be somewhat redundant,

Not if you start a voltage and current metered Variac at 0 volts and slowly bring it up. I've been powering up sets for the first time that way for more than 40 years without damage. -- Dale H. Cook,

Dale H. Cook <bridgewaterma@...> wrote: A variac is nice, but a dim bulb can be more useful; if you're uncertain of the condition of a set, a dim bulb will tell you at once if there's

Call me overly cautious if you like, but in the case of an unknown and untested DUT, I take a belt and braces approach. So for me it's a dim bulb tester in series with a variac in series with an

This has been used for decades by those who restore antique radios, and we call it a "Dim Bulb Tester." I don't use one because I own an isolated, fused and metered Variac. -- Dale H. Cook, GR/HP/Tek

I would probably use two logins to create two accounts and put half on each drive. Would be within 15G limit on each that way. Each drive could have a link to the other. No cost. Regards

Looks like a low cost version of 8901A …

Does anyone have the manual for the JSR RM3500 automatic modulation meter? Thank you. Marcelo F. Ruiz

Just so I don't take credit that's not mine, I only re-labeled the sketch in English from the original Dutch(?). Mikek

Well, the oscillator (TM1247) is 20-300 MHz. Presumably it covers this range, although as the note says .... up to 4V depending upon frequency. (one suspects that it rolls off at the extremes)

Hello, does not state frequency range ? regards john davis

Get another book 8-)

You can gist the size of the HP4342 from the exploded view and pictures in the service manual.? The turns ratio is 50:1 and I believe the construction is a toroid inside a conductive cup with a

Thanks Mikek, Yes that scheme would require even more power, a total of about 1.5 watts just to get 20 mW into the Q measuring circuit. Another method might be to cascade a couple of transformers with

Back in the Q meter thread someone gave just enough info to make it sound interesting, but not enough for me to understand. Their design was for 50Ω, They used a 40Ω and 10Ω in series and put the

My biggest hurdle in producing an exciter for the TF1245 has been? the design of the matching transformer. The TF1245 requires 0.5 watt at an impedance of 0.5 ohm which means a current of 1 ampere

Hello, Incorrect information The TM5728A is a matching tranformer for a 600 ohm source (1 to 40Khz) for use with the TF1245 in my book there is no TM5727 ? regards john davis

I've got the TF1245A with both the TF1246 & TF1247. The TF1247 also comes with an 'adapter' (TM5727) to 50 ohms. Presumably this could be used in reverse to match 50 ohms to the low impedance of the Q