Once the chassis is cleaned, I replace any bad capacitors and resistors based on a visual inspection. Anything that looks like its leaking or is burned gets replaced. All paper caps get replaced. Everything else gets tested with a capacitor tester and multimeter. Any dry rotted or cracked wiring gets replaced. The panel light was changed. Then I connect an external speaker and antenna and slowly power it up using a variac.
Some bad components that were changed.
After powering it up. I was able to pull in a few stations on FM. Nothing worked on the other bands. The next step was to clean the pushbutton assembly contacts. These are notorious for not working on vintage German radios. I use DeoxIT contact cleaner and keep spraying and working it in on all contact points. After completely drying I power it up again. This time I can get static on the AM and SW bands.
Next step is to test all the tubes. Unlike many American sets that I worked on, the tubes in these European sets will test good on a tester despite having issues. The ECH81 tube is a triode tube which effects both AM and FM. One band can work while the other is dead and the tube will test just fine on a tester. Upon swapping it out with a good tube, AM came alive although on low volume. I then swapped out the EF89 tube (which effects amplification) and all bands now work fine.
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