Kenwood KA-7002 relay click power up

One thing I did notice was that when I power off, the music continues to play for a bit and also right towards the end it gets really loud so I suspect it might be the Main Filter caps that could be bad.
 
plyzo said:
I think you are right. I’ll have to pull out the scope. Need to figure out the test points I should be checking.
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Pins 1 & 22 LR inputs. Bases Q5, Q6, Q9, Q10, Q11 and Q12. Start at inputs and work toward outputs. Turn volume and balance pots while watching signal on scope for noise. 1 khz sine wave should be smooth and signal amplitude should be equal on odds and evens. Left channel to Q5 right to Q6. Left Q9 and right Q10 etc.

Signal should clip at around 20-22 volts RMS at speaker outputs into 8 ohm dummy load.
 
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Of course it something simple! I took another look at the driver board before getting the scope out. I totally forgot to populate a 1uf cap on the board. Wow, that is a first. Got ahead of myself and must of missed that. Unit is sounding great! Thank you @analogwisdom for your help.
 
Glad you got it working, you did the legwork. Sometimes it's good just to talk to someone else about it! Nice work :thumbsup:
 
analogwisdom said:
Glad you got it working, you did the legwork. Sometimes it's good just to talk to someone else about it! Nice work :thumbsup:
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Thank you. I knew if I posted on here that I would get some help in figuring it out. There are some great people on here to help and at least like you said, converse and giving options to help with diagnostics. Thank you again!
 
Hello, I will join the topic, I recently purchased a beautiful 7002 and I am wondering about the operation of the speaker relay. It is always on, there are no clicks at on/off. So it disconnects the circuit only in the event of a fault? In the 5002, the "standard" click on on/off behaves.
 
Dart07 said:
Hello, I will join the topic, I recently purchased a beautiful 7002 and I am wondering about the operation of the speaker relay. It is always on, there are no clicks at on/off. So it disconnects the circuit only in the event of a fault? In the 5002, the "standard" click on on/off behaves.
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Yes, you are correct. There are three different versions of the protection circuit of the KA-7002. The earliest one uses a NC (normally closed) relay that opens if a fault is detected, disconnecting the speakers.
 
analogwisdom said:
Yes, you are correct. There are three different versions of the protection circuit of the KA-7002. The earliest one uses a NC (normally closed) relay that opens if a fault is detected, disconnecting the speakers.
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thank you for confirming... what does the null balance function do in practice?
 
Dart07 said:
thank you for confirming... what does the null balance function do in practice?
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There is a section in the KA-7002 Owner's Manual about it, as well as several past threads here on AK where the function has been discussed. I'll leave it to you to find those on your own :thumbsup:
 
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