Sound quits and it clicks
Great Kenwood Eleven III reciever works for a while then goes silent after a click sound is heard
Kenwood FM stereo receiver Model Eleven III. This stereo is from the 1970s.
Here is my 2 cents worth on fixing Audio Amplifiers/Receivers:
Many use single sided PC boards for the analog sections.
Output transistors and connectors are mounted onto sub-assemblies (e.g. heat sinks) and the leads soldered into the PCBs. Over time, vibration and thermal expansion/contraction cause the leads to push the the solder joint and underlying PCB trace off the single sided board. The trace cracks and you get intermittent or no connections across the break.
I have had this issue with two Sony and one HK 5.1 receivers in just last the couple of months.
If you feel comfortable working around high voltages (120V DC is not unusual for high power amps)- take off the access panels and tap around the single sided boards with a NON-CONDUCTIVE probe. If you are lucky you will identify the broken joint. You can then power down, WAIT FOR THE SUPPLY CAPACITORS TO DISCHARGE (remember you can still get zapped even a long time after the power cord is disconnected!) then re-solder it.
I'm also an EE, but fixing audio is just a hobby ;-)
What other symptoms?
Power indicator on? If not, check things that affect power, like circuit breakers (things that reset, obviously not fuses).
Does it consistently take the same amount of time to shut down?
Can you affect the amount of time to shut down by removing heat (removing case, or routing an air source into the receiver)? If so, you can selectively spray a cold source (used to be trichlorotrifluoroethene - outlawed, so go to Radio Shack for current troubleshooting aid) on internal areas to see if the receiver will reactivate. If successful, start isolating to smaller and smaller areas, until offending component is found.
I'd have to look at it to provide help beyond this. Unless you have experience, your chances of success are small. A good technician is worth the money. I'm a EE, and been troubleshooting for nearly 40 years.
Make sure your timer is making a noise. Turn it on clockwise until you hear it click. If it does not click it is the shaft that is broken and needs repaired. You will have to find someone who know how to do this and research to do it yourself.
Note: HIGH VOLTAGE INSIDE! Not responsible for accidents!
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