What is the correct operation of the stereo indicator lamp on an SX-737?

[triplegee77]

I restored this SX-737 and everything works great, but I am trying to figure out the correct operation of the stereo indicator lamp and I can't find a definitive answer. Currently, the stereo indicator lamp functions in all modes except AM. For example, if I am in AUX mode and the tuner is tuned to an FM stereo signal, the stereo indicator lamp illuminates. I have read that the stereo indicator lamp should only be on when in FM mode and tuned to a stereo signal. But when I look at the function switch, it appears that it was designed to maintain B+ voltage to to tuner board in all modes except AM. Therefore, the HA1156 chip still has power and will illuminate the stereo indicator lamp if tuned to an FM stereo station. Am I looking at this correctly? What is the correct operation of the stereo lamp?

 

[Mwdan]

I asked the same question a long time ago but not as detailed and was told that it was normal for the stereo indicator light to come on if it was tuned to a station even if the unit was in auxiliary mode.

 

[triplegee77]

I asked the same question a long time ago but not as detailed and was told that it was normal for the stereo indicator light to come on if it was tuned to a station even if the unit was in auxiliary mode.

Thanks for the reply!

 

[kwayde]

I restored this SX-737 and everything works great, but I am trying to figure out the correct operation of the stereo indicator lamp and I can't find a definitive answer. Currently, the stereo indicator lamp functions in all modes except AM. For example, if I am in AUX mode and the tuner is tuned to an FM stereo signal, the stereo indicator lamp illuminates. I have read that the stereo indicator lamp should only be on when in FM mode and tuned to a stereo signal. But when I look at the function switch, it appears that it was designed to maintain B+ voltage to to tuner board in all modes except AM. Therefore, the HA1156 chip still has power and will illuminate the stereo indicator lamp if tuned to an FM stereo station. Am I looking at this correctly? What is the correct operation of the stereo lamp?

View attachment 3825780

I just worked on one and this one is like yours, the stereo lamp is lit with other functions.

 

[triplegee77]

I just worked on one and this one is like yours, the stereo lamp is lit with other functions.

Thanks.

 

[pa_200]

As far as I remember, the tuner is always on, no matter what you have selected. The stereo indicator is only off without a Stereo-signal, with MONO selected or if you switch to AM.

 

[triplegee77]

As far as I remember, the tuner is always on, no matter what you have selected. The stereo indicator is only off without a Stereo-signal, with MONO selected or if you switch to AM.

Thanks. Looks like this is the general concensus.