Konzertgerät 4097

Experience 4097 restoration

• Overall, beautiful radio. Extensive soundscaping abilities with a cute analog visualization of the soundscape, equalizer-like. 

• The radio delivers an OK sound experience, nothing dramatic, but it does the job.

• SW/KW was very selective, to my surprise.

• FM needed a lot of tuning

• Experience

  • Almost all capacitors needed replacement; some were sadly deeply hidden and required disassembly to access. Lots of capacitors for the soundscaping, which meant a lot of work, but worth it. You will need to dismantle the soundscaping selector block; several capacitors are hidden behind it.

  • A mechanical selector extension extends the piano selector to the switches further back in the radio. This is a beauty, but in my case, VERY clogged with old grease, and a number of springs had left the building. Clean-up was easy, and for replacing the springs, I cut some from ballpoint pens down to fit. I also used a flexible glue to tie the springs down at both ends to hopefully prevent them from traveling on their own in the future.

  • I also needed to dismantle the volume control block to access all the capacitors. The volume control itself remained a bit shaky in spite of multiple attempts to fix.

  • Resistors all good, no replacements needed

  • There was a 6V bulb used in the amplifier circuit as a power delimitter (?); this needed replacement

  • Indicators of the selected soundscape were tiny 6V bulbs, which were hard to find new ones due to their size. Replaced with blue LED’s & resistor duos, just plugged in as a replacement into the existing sockets. Find ones that can take the raw 6V DC. This was a nice effect.

  • The soundscaping orchestration was visualized as a neat musical bar graph connected by a red line/elastic, which has since disintegrated. I replaced it with red stretch sewing thread and weaved it back and forth a couple of times. There is a red post per pot; I carefully wrapped the thread around them, and I fixed them down with a small drop of super glue.

  • As usual, make extensive notes and pictures, it is easy to get lost in this complicated radio

  • The piano key switches were very dirty and required extensive cleaning. 

  • The case cleaned up nicely.

Anexos

• 4097 (255 KB)

Ben Brand, 20.Apr.26

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This is one of the most complicated I have undertaken. 
- ALL, yes ALL capacitors are way out of spec
- A large number of the capacitors are built into hard-to-reach places. Major disassembly required.

Make copious notes when disassembling, it is really easy to get confused. 

Reach out if you need help.


 

Ben Brand, 09.Jun.25

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