Kenwood KR-9400 No Stereo light in FM, no audio with FM mute on.

[SAS73]

Dear friends,

I am trying to troubleshoot an Kenwood KR-9400 , low beacon voltage ( 0.78 VDC) Tested Qb7 and Qb8 seem OK. tried to adjust Lb5 , little more voltage after adjustment but not by much .
General question : What is exactly beacon signal does ?  Is it  just for a stereo light indicator, and FM mute circuitry ?

Thanks!
 

[darkspr1te]

On my old Kenwoods FM muting would mute NONE FM transmitted stations, so if you get no audio even on FM tranmissions with it on then its possible theres a issue the fm decode or seperation


look at board x04-104010 coming from FM IF board , it shows the stereo signal system. Also later on in the manual is shows the voltage readings for setting most of the VR's
this is from the manual found at
https://elektrotanya.com/kenwood_kr-9400-service-manual.pdf/download.html#dl


darkspr1te

[SAS73]

Thanks for reply !
I have a very good FM RF signal from antenna ( I had also tried signal generator) but if I press FM mute, no audio, probably because i don't have a 5 volts on TP5 terminal ( beacon), I had injected 5VDC to that terminal and FM mute works, the question is why I don't have 5 volts on that terminal?
I had tested all transistors and diodes on IF board. All tested good.

 

[darkspr1te]

Did you download and read the service manual I posted?, i has a trouble shooting section that gives a flow chart of failure and what to check.




darkspr1te

[SAS73]

Yes, I downloaded SM, replaced HA1156 , realigned according service manual , receiving in Stereo now, FM mute works also , THANKS