As promised earlier, we ordered some parts and began working on this radio last week.
I just completed the power transformer rubber wiring repair and this is the first one of these transformers I have done. I also repaired the rubber wiring on the output transformer. I also replaced the old power cord with a new polarized unit.
Now I am in the process of replacing the 3 electrolytics and all of the paper capacitors.
Tomorrow I may apply power and see how the power transformer measures. Will something smoke? Stay tuned to find out!
When powering, first remove the 84 rectifier, power without it. This way you will check the tansformer.
Then you can do the rest.
Also, check the tubes, especially rectifier the tube, if it is shorted (which happens more often then one might think) it can take out your el. caps nd the transformer.
Well, good news, the transformer seems to be working fine and running cool! I must have done the repair job correctly....
I want to show you the neat little fixture that I started using while doing this radio. Just go to your local home supply store and find one of these 12 inch turntables. Then add on a large enough piece of plywood to support the most common size radio you will work on. Being able to spin the radio easily and work on it from all directions is a real time saver!
The electrolytics and most capacitors have been replaced. Now the radio is playing, but not very well. It passes a signal from the generator all the way through but not much volume. So when I have time I will be looking into the first IF transformer for a possible open winding in the secondary.
Okay, at this point in time, here is what's happening with this..... It doesn't receive any stations AM or SW.
(Power & audio transformers rewired, caps replaced, dial lamp rewired and much rubber wire replaced.)
The voltages match the schematic closely through out the radio.
The audio section is working ok.
A 470kc (if freq.) signal injected at the Antenna terminal is heard from the speaker. Volume control works.
The local oscillator ( am ) runs and can be heard on a test (am) radio.
So I hook a longwire to the antenna terminal and no stations are heard AM or SW. I will continue roubleshooting.
No, the sig generator does not pass thru on the broadcast band or SW band.
I just found my wiring error on the band switch on the AVC Line. I put the .05 cap on the wrong location on the switch to ground. This happened while I replaced the rubber wiring and capacitor on the band switch.
So, I have to pull the band switch back out of the chassis and move the .05 cap to the correct terminal. That band switch is a pain to work around!
I moved that .05 AVC cap to the correct place and started to hear RF noise coming thru.
Did a quick If and AM band and SW band alignment and now it's working. It seems that by tweaking those alignment adjustments, the trimmers and padders must have been worked free of the dirt and grime and they are now working. So now I will run the radio for a while to burn in and watch for problems.
