My Kenwood KR 9340 is in protection. The values I'm getting are below. I've been trying tp figure out why voltages are so off especially the base voltages. Attached is the schematic along with the correct values. Would greatly appreciate some knowledge on this problem as I'm obviously lacking. Thanks in advance
B C E
Q14 -34 35 -34
Q17 -35 -34 -34
Q1 -34 -35 -18
Q5 -9 -35 -18
Q9 -35 -35 -35
B C E
Q14 -34 35 -34
Q17 -35 -34 -34
Q1 -34 -35 -18
Q5 -9 -35 -18
Q9 -35 -35 -35
Attachments
Hey thanks for your response My wife picked this up at a estate sale. It hasn't worked but I see that someone has done some work to the main AMP board. I've gone through it a few times fixed several mistakes. Of the four channels all are in voltage spec except the the back right. I tried to troubleshoot some today but did not find the problem. I'm getting the voltages below now. Any ideas?
| B | C | E | |
| Q13 | 35 | 35 | 35 |
| Q17 | 34 | -35 | 34 |
| Q1 | 0.152 | -23 | 0.756 |
| Q5 | 9.8 | -34 | 0.754 |
| Q9 | -shi | 34 | -22 |
Hi,
We need some more detail re the Q9 voltages. What does "-shi" mean?
Would you report the voltage on the -35V rail as observed at Re19 and Re29 resistor leads? Q9 emitter is -22V which is suspect. Would measure the voltages across Re19 and Re29. Maybe these will give insight about Q9 voltages re the negative rail.
Thanks!
We need some more detail re the Q9 voltages. What does "-shi" mean?
Would you report the voltage on the -35V rail as observed at Re19 and Re29 resistor leads? Q9 emitter is -22V which is suspect. Would measure the voltages across Re19 and Re29. Maybe these will give insight about Q9 voltages re the negative rail.
Thanks!
Some of the data seems inconsistent. Note Q1 collector insight reported as -23V and Q9 base as -31V, but these nodes are supposed to be the same.
I’ll describe what should happen given Q13/Q17 emitters are about +34V.
Q5 base is pulled much higher than Q1 base, so Q5 should be cutoff and Q1 should be conducting. This should cause Q9 to conduct and pull output stages negative.
Explore at base of Q9 to learn why Q9 doesn’t appear to be conducting. Base of Q9 should be about 0.6V above emitter. There should be some voltage across Re29 indicating current in Q9.
I’ll describe what should happen given Q13/Q17 emitters are about +34V.
Q5 base is pulled much higher than Q1 base, so Q5 should be cutoff and Q1 should be conducting. This should cause Q9 to conduct and pull output stages negative.
Explore at base of Q9 to learn why Q9 doesn’t appear to be conducting. Base of Q9 should be about 0.6V above emitter. There should be some voltage across Re29 indicating current in Q9.
Last edited:
Hey followed your tip and found a cold solder joint between Q5 Collector and R29. Repaired and and it came out of protection and actually played music. Went back about a hour later and the lights went bright on my dim bulb. tester, Al seem well until I connect Q13 emitter to R45. System comes out of protection but dim bulb indicates there is a short. I'm trying to find the short. So far no luck
Thanks
Thanks