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Clean the switches. You will find lots of info in the group message archive. I usually use a good non-contaminating spray or a DeoxIT cleaner in a needle tip bottle, followed by application of DeoxIT

David, Consider everyone’s response, so not to be offended — no one ignored you; it may seem that way, though. ? We all learn from all the posts, no matter how much experience we have or

Absolutely. Many of us are non-engineers and appreciate the insight. Steve Wedge, W1ES/4 Time flies like an arrow. Fruit flies like a banana. Sent with [Proton Mail](https://proton.me/) secure email.

Success! I now have a fully functional Power Master, thanks to a Christmas light controller that gave up its outlets for my re-purposing. A BIG thank you to Steve who happened to mention in your note

One other thing that needs to be considered in testing some tubes, particularly power tubes, is the impact high plate current can have on readings. Most Hickok tube testers use a single transformer

All things considered the values are reasonable. First, the datasheet value is a target or "bogie" value based on the design and average of production. The tolerance for tube characteristics is

I have a bit of tube background myself. I can state with certainty that variation of +/- 15% is not uncommon. That is why some folks get paid decent money to match tubes to +/- 5%, about as good as

Whoa, wait a minnit, you changed the capacitor and the distortion went away? And its a mystery? Am I misreading this? -- Richard Knoppow Los Angeles WB6KBL SKCC 19998

Richard, you seem to be? knowledgeable about tubes, so please let me throw a question at you. A friend lent me a Westinghouse carton of 5? Westinghouse boxed NOS 6CB6 tubes. All have identical

David, I agree with Gary’s response. I liked your comments. 73, Bill KJ5BNE ++++++++++++++++ Bill Blodgett Arlington, Texas

Whoa David. Not sure what this refers to but I am pretty sure we all appreciate your insight and help. In fooling with broken old radios, nobody has an exact answer, we have to work around the problem

Yup, sometimes you gotta savor the victories! mike, wb8vge

Hi everyone, I wanted to update the progress on my SW4A problems with the AGC causing distortion with strong signals. Over the Christmas holiday, I installed the tri-section electrolytic capacitor I

Great Steve.? I love it when we find a solution and save an old Drake! Darn, I sure wish we could? go down to the store and buy a new tube.? I am suspicious of any tube now, they are all as old and

Richard, YES, you are da man.? I have learned a lot of valuable info from your posts, keep them coming! 73, Gary WB6OGD

Update: First, thank you all for the info and help. I took the DR7 out and cleaned it with deoxit. Especially the pins and contacts in the rear corner, that I knew were causing problems. That fixed

My first rig was a Swan 500. Shortly afterwards, my Elmer also sold me an R-4A that didn’t work. That was my first piece of Drake gear and I wish I’d kept it but I didn’t. I used a Johnson TR

Happy new year dear friends! Had some time to spend, the TR7 is now fixed. As Jim suggested, I could not find any obvious fault in the VCO board. I think the fault was due to the very tight boards

I missed a point about tubes. All tubes will drift when warming up. Simply the the spacing of the electrodes and their dimensions change with temperature. Most things expand when they get warm, so do

UPDATE One very bad tube (V5, I think. I should have marked them when I removed them!). Three that weren't great but had passed on the tube tester. V3, V4 and V9. There is still a change in voltage