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Hi Mark, Great questions! I have always considered this mod to be unnecessary and potentially problematic. Which you seem to be finding out. Adjusting the threshold level at U1601 could be a better

Be sure that the SIDEBAND switch is on "X-CW". If you're tuning in CW mode, you either need the KEY jack to have nothing plugged in or close the key contacts. Likewise, if you transmit on SSB and have

I have found that measurements vs the charts in the manuals will vary all over the place. If one point in the manual calls out 75V and you're measuring 80V, that is likely just fine. If the expected

https://www.amazon.com/Fiberglass-Scratch-Brush-Pen-Applications/dp/B0C31DXTR4

My recently repaired TR-7 still working well:-) I have implemented Jeff Covelli's mod. http://www.wb4hfn.com/DRAKE/DrakeArticles/TR7_ALC_Control/TR7%20ACL%20Control.htm to make the front-panel

I went through the tune up procedure and everything looked good until I got to the last step and the plate current never goes above .1 on the plate meter. I have set the bias with the PS per the

On Fri, 15 Mar 2024 14:57:51 -0700 "Lyndon VE7TFX" <lyndon@...> wrote: When reading the voltage charts in tube radio manuals, the numbers you measure with your DMM likely won't line up. That's because

I sort of already mentioned that in message #76705. :D "n4buq" <n4buq@...> wrote: -- 73 -Jim NU0C

It'll come up eventually, but what also separates a typical VTVM from a DMM is the analog meter movement It's hard to beat that when tweaking a tuned circuit. I love my HP-410Bs and HP-410Cs. Barry -

A DMM works fine if you are measuring pure DC or very low frequency AC as in a power supply. Where you get into trouble is if there is any RF present. The same applies to a scope probe, whether or

Howdy folks! I’m in need of a front panel for a Drake 2BQ. Mine has a fair amount of rust on it and has had since I bought it at Belton many years ago Anyone have a parts unit they will sell me the

And this is why you want to be aware of Heathkit VTVMs in particular, and maybe others, where hobbyists who thought they were smarter than the engineers thought it was a cool idea to move the 1M

That's the best answer and explanation so far.? What separates a VTVM from a DMM, both of which may have the same specified input Z...is the isolating tip resistor.? When taking measurements at

If measuring the grid of a tube , especially one used as an oscillator you often need a meter with a resistor at the end of a probe.? That is why most of the old VTVMs have a 1 meg ohm resistor at

"Lyndon VE7TFX" <lyndon@...> wrote: Appreciate the feedback.? I didn't expect the voltages/resistances to be identical, and yes I went through the entire process out of sheer curiosity and for

100 kHz Crystals used in Crystal calibrators are available (new and used) from various sources. The HC-13 crystal holder size use to cost ~ $13.00 each , BUT with the closure of ICM in Oklahoma City a

*** Or just download them for free: https://www.worldradiohistory.com/Popular-Electronics-Guide.htm - Jerry, KF6VB

I am working on restoring a Drake 1A and the calibrator doesn’t oscillate. ? ?I tested it a simple crystal tester circuit and confirmed that it does not oscillate. So will baking it worth a try?

Fifth Edition is here. https://www.worldradiohistory.com/BOOKSHELF-ARH/Technology/Technology-Radio/Elements-Of-Radio-5th-Edition-Abraham-Marcus.pdf 1947 edition.

I came in to ham radio toward the end of the vacuum tube era, but they had stopped teaching tube theory by the time I got to engineering school.? I remember asking a professor once about tubes, and