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Kenwood KR-5200 no stereo in FM

C

chyde99

New Member
Hello, I’m pretty much new to this so any help would be greatly appreciated. I have a Kenwood KR-5200 and I have no stereo in FM only and also no stereo light. I have checked the bulb and it is good and also I am getting great reception. It just doesn’t play in stereo when playing FM. Everything else such as phono and AUX play in stereo just fine. I have cleaned all the pots and switches as well. I would love it if someone can point me in the right direction. Thanks in advance!
 
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When this is an issue I would estimate that at least 90% of the time it is an alignment issue. Did a quick look at the procedure, this is older tuner so no easy VCO adjustment to get the stereo back.
 
Thanks so much for looking in to this for me. I may need a tech for this alignment if I find I am unable to do it.
 
Screenshot 2022-03-02 124224.jpg Screenshot 2022-03-02 124304.jpg

Locate the MPX board, and put your voltmeter *across* VRc2. Post the voltage you see when tuned between stations (prefer with antenna disconnected) and when tuned to a strong stereo signal.
 
Would have liked to see a greater differential, but that may be OK. At least it tells us there is some 19 KHz pilot tone making it into the doubler. Let's check the 'gate' signal. Find the board terminal 8 and measure the voltage with no signal and strong signal.
 
Again, it is enough to indicate a signal is getting though, but seems a bit weak. Try this -- Locate the collector of Qc4, RC36 and Rc38 should also be at that connection. Add a jumper to ground and see if the receiver performs any different.
 
Monitor the voltage at the board terminal 10. When you ground Qc4 collector, terminal 10 should go high (>5 volts).
With terminal 10 high, that should supply base drive to Qc7 - turning on the stereo lamp.
 
May be a burned out lamp - can you get your ohmmeter across the bulb to confirm continuity?

With the short from Qc4 to ground removed, measure the voltage at board terminal 10 both with no signal and a strong stereo signal.
 
I had visually inspected the bulb and thought it was good. I had to tear up the rubber grommet taking the bulb out to check for continuity. Yes, the bulb was bad. I had a led from another unit sitting around and installed it. Works great! Now to figure out why I’m not getting stereo when playing FM. I get stereo in all other modes. Thanks so much, you have been a great help.
 
So now you are getting a stereo light when tuned to a stereo station? That would mean the gate signal and the 19KHz pilot level are sufficient.
 
So the MPX board is seeing enough signal. When tuned to a stereo station, what are you seeing for DC voltages on Qc3?
About the only things left that could be at fault are Qc3 and Lc4.
 
Ok, at Qc3 I’m getting the DC voltages when tuned to a stereo station.

2.1v Collector
14.2v Base
1.5v Emitter

I think I have the pin order right.
 
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