Hello-
This is my first post to the forum and my first AA5/AA6 radio repair removed link I’ve been following along all of the Mr. Carlson’s Youtube videos for a while now and I wanted to take part in the forums!
I’m well aware of all of the safety issues regarding these transformerless radios, and I am not a newbie to electronics. I’m here to ask questions, learn, and share my progress along the way.
I don’t have much test gear beyond basic DMM and that’s it really. I’ll see if I could borrow help from others when I get to the alignment stage. I have some “more equipped” ham radio buddies with VTVMs and RF Signal generators…..
2 of the 6 tubes tested open when I checked the filaments; the 35y4 rectifier and 7c6 (detector/avc/af). My guess without checking would be failed caps and shorted out blowing the filaments. No worries, my friend has been in the tube business for 40 years and I know where I can find replacement NOS. I’m putting together a dim-bulb tester with a 1:1 isolation transformer to run these projects when I test and play them. I’ve done all the research and have already replaced most of the capacitors, but I had a question about a few things:
Resistors
I know all of these radios usually have the AB-style resistors. Beyond keeping with the spirit of replacing those with the same, could I use less expensive alternatives? Is there any reason not to do so electronically?
Tuning Cap
Cleaning. How do you all clean out 70 years of dust that has collected on the air-variable cap plates? I was thinking a paintbrush with Dawn dish-soap? Then air blast it to remove junk?
Wood case and plastic cleaning tips
Any good product(s) to clean and polish? Make shine again? I’ve seen Mr. Carlson use VIM on the metal chassis.
Alrighty, thanks. TTFN!
Matt
K9EI
Welcome, sounds like you are off to a great start. Test equipment will come, I have more stuff than I know what to do with and it keeps coming (by choice). Tubes are still easy to come by for the most part. The rectifier could be failed from a cap, the other is likely just bad luck. As far as resistors, bad ones can be replaced with an equivalent metal or carbon film generally. Only reason to use carbon comp is for originality or the circuit is critical of stray inductance. That is pretty much the way to clean those, hose them down, scrub what you can, and blow it out. Relubricate when done to get it moving smooth. Depending on the case, light cleaners and polish, Howard feed n wax for wood gives a nice look and protects.
Radios + Tubes + Scopes + Cars= Nothing better!
Thanks for the reply. I got the chassis cleaned up and dusty grease cleaned up. I went with WD40 for the gears and cap plates. A toothbrush and air can worked great. I used some Bar Keepers Friend for the chassis which gave it a cleaning and polish.
New resistors, line cord, and term strips got here last week. Slowly but surely it is coming back together.
Matt