Goodwill purchase. $2.99. Realistic model DX-440 "Voice of the World" portable
0) No power on with 9v wall adaptor
1) Initial inspection revealed green crustiness on the center pin of the 9v DC in jack.
2) slight corrosion on the springs/negative contacts of D battery holder (6x1.5 "D" plus 2x1.5 "AA" for memory. I hit them with
3) unit powers on with D-cell batteries and I can clearly tune in 90.3 (local NPR FM station) but no sound out of main speaker (dead silence). The led signal strength meter (1-5 LEDs) goes to 5 so I know I am getting signal.
4) AKG headphones (known to be good) into 1/8" headphone jack give some signal but with these issues
5) Antenna is loose at the pivot bolt, but I believe it is working as I can tune in stations.
a) constant pop-pop-pop at regular intervals and when popping, the audio is not heard
b) popping continues for a bit after unit is powered down (power on off is a momentary switch, not a make break mechanical)
c) no effect with the volume slider (unit stays at constant volume regardless of slider position
I am thinking filtering in the power supply, but I am no EE and I usually tinker only with vacuum tube guitar amps. The closest thing I could guess, was that it was something with a bad electrolytic filer cap in the power supply.
Will post some shots, ASAP when I get back cover off.