Kenwood KR-5200 no stereo in FM

[Deceders]

Hi, I inserted the data into your post. The reference to vac is a typo. Q1 - I provided B,C,E as per the circuit board.

 

[Ylli]

Qg7 Base - 2.86
Emitter - 0
Collector - 14

This is indicative of a bad transistor (open B-E junction). Remove this one and test it either with a transistor tester or with the diode function on your digital multi-meter.
https://instrumentationtools.com/testing-a-transistor-with-a-digital-multimeter/#

 

[Deceders]

Yes, it's toast. 2SC535 seems to be not readily available from my local electronics store, or mouser, or digikey. Just going to now research an alternative. Thanks!
Looks like some folks are using 2N5770, this one is available.

 

[Ylli]

Its not going to be real critical, just about any NPN with a high enough Ft and voltage ratings should work - just watch the pinouts. Otherwise, B&D seems to have the original 2sc535 is stock: https://www.bdent.com/2sc535-hitachi-high-frequency-transistor.html . The 2n5770 is a bit marginal on the voltage rating.

 

[Deceders]

Ylli,

Thanks so much for sharing your experience. FM stereo is back online. This was my first transistor replacement. Very rewarding.

 

[Ylli]

 

[rzepska]

:banan: mój kościół:

Hello. I have a problem in Kenwood Kr 5200. The radio does not work in stereo, sometimes I manage to catch a station in stereo but the sound is not clear. The Stereo backlight does not work either. However, when I put a jumper to the Qc4 collector, the lamp starts to light up. With the antenna disconnected, it is also difficult to catch radio stations. I measured through VRc2 with the antenna disconnected and I get 1.01 V between stations and 1.2-2.5 V when receiving a radio station... Can you direct me where to look for the cause of the problem? Best regards