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The simplest way is to connect an external tone oscillator to pin 8 of J3 Through a diode. [cid:b3cca5bc-b43e-43a3-91b8-1e3628d7d5d5] Walt Cates, WD0GOF https://wd0gof.com/Hallicrafters A majority

Good day all I enjoy using various vintage "separates" on CW, with a bug. The common issue is what to do for sidetone when using a straight key or bug. Typically,? not music the Rx, and have a fast

Common practice back in the "good of days" when we were a lot more creative. Maybe original owner didn't want the preamp "box" hanging off the back end of the receiver and he had room inside the

Anyone seen one like this?? I bought this off eBay years ago and it's been sitting in a box until yesterday.? Took it out for a look and was surprised to find that I had two more tubes than shown in

Walt and Jacques - Thanks for your kind offers. It is nice to know I have options. For now the series capacitor combo that I have been tweaking is adequate. Drift is much better than before. So I am

Jerry, I found a 82pF, N080 capacitor in my parts "inventory", it seems to be NOS, but it test at 92pF. See attached. If ever you may need it, just send me your mail address, in case that

I have found that 82pf N80 difficult to find also. I have successfully used an 82pf N30 as a replacement. I have a couple left. If you have no luck finding an N80 shoot me an email at cateswa at msn

It looks like the problem was one of those big offenders you mentioned Walt. Specifically C85 82pfN80. It measures 82pf but seems to have lost it's temperature compensation characteristics. Now the

we are in the wrong group but i own an A300 that uses 7408/6v6 output. simple amp w/a great sound w/only 12 watts out. barry ________________________________ Sent: Sunday, December 1,

Thanks you Walt. I appreciate all your help. I will try to implement your suggestions tomorrow.

Well, that's the reactance of an inductor. Someone measured the inductance with a bridge. That measurement may or may not change with the level of the drive from the bridge. In any case what I

Richard, The old formula I learned is X= 2πfL. for 60 cycles--- 6.28 *60* 12 = 4521.6 [a lot of X-ohms ] compared to 85 R-ohms, but that must be the magnetizing inductance at some low

This is still an odd transformer. There have been systems of color code for transformer leads for many decades. In some cases manufacturers had their own codes, usually shown in their catalogs. In

Walt and Jim and All Black wires in and red wires out remind me of typical B+ power transformers. B+ for transistors were low voltage back then, so maybe you have a low voltage B+ rectifier

Jerry, I looked up some of my old repair tickets from the 90's. I found some other things you may try. Chassis corrosion and grounding were problems on several tickets. Remove the mounting screws of

WaltYou can always apply 12VAC to the black leads and measure what what is on the red leads.? Still feel that it is an AC step down power transformer. You should put your call on that document.?

Jim, That list you attached came from my website. That is what is so confusing about this hunk of iron. Those colors don't match any standard. ?? Walt Cates,

All thing are possible since transformers are bilateral.? Typically, audio transformers do not use two black leads or two red leads for that matter and the laminations are usually thinner then those

The big offenders in the 46 VFO are C84 10pf N750, C85 82pf N80, C86 100pf NPO, C87 47pf NPO and C89 82pf NPO. These 5 capacitors are all 20 years past their useful life. I would replace all 5. You

The VFO in my newest HT46 has excessive drift. In standby mode it will drift about 1KHz in the first 15 minutes and then go another 600Hz in the following hour. The VFO drifts downward in frequency so