HK330A Doesn't Want To Do Stereo

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This H/K receiver is acting funny FM-wise. The signal strength meter is dead in FM, but only in FM, it works fine in AM. In addition, channels come in fine in FM mono and when you switch to FM stereo, the signal still comes in on mono (no stereo) and I have a good antenna. The FM beacon glows dimly and continuously when the unit is on and in all modes The schematic can be found here:

http://www.eserviceinfo.com/downloadsm/22097/Harmon Kardon_330A.html

Scroll down a bit for the link just under the "Download Restrictions" box.

Using a good viewer like Brava, the schematic is readable, I have found other viewers are finicky with .TIF files.

The only measurement I have made so far is at the stereo/mono switch, I get 104K Ohm in stereo and 0 Ohm in mono.

Any comments appreciated.
 
The hk 330A uses a discrete switched envelope decoder that is not mono /stereo compatable. Hence you will get no output on stereo if the 38 khz carrier is not being generated.
Do you have a scope?
If so trace the pilot 19 khz tone and then through the frequency doubler to 38 khz
First suspect the freq doubler transistor
I have had these fail in the past
regards Trev
 
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