I picked up this Kenwood KA-305 for my son and it has no right channel on the Phono input only.
The rest of the inputs seem ok although maybe the sound is not as good as new, it is close.
I have some very basic knowledge of electronics and have a multimeter and the service manual.
Upon close inspection, the right channel IC had two pins that the solder was not on. I do not know if the previous owner attempted repair or not.
If you look closed at the IC pins (in the photos I will post), it does appear that someone touched up or changed IC for left channel as one of the pins looks kind of dark to me.
Anyway, I resoldered the right channel two pins best I could. I made certain there is no short across the pins BUT when I powered back up, left channel is fine and right is still dead.
However, this time the right channel starts to get hot and after 2 min I powered down for fear it would overheat. It seemed to be just getting slowly hotter. I did not want to take a chance before I asked for an option from those who have experience.
Can someone please tell me what my next step should be?
I would appreciate the help.
Photos can be found here:
https://www.dropbox.com/sh/buaxlxajrv7ztc4/AAAISWMAtqXahMiRjjILt61ka?dl=0
The rest of the inputs seem ok although maybe the sound is not as good as new, it is close.
I have some very basic knowledge of electronics and have a multimeter and the service manual.
Upon close inspection, the right channel IC had two pins that the solder was not on. I do not know if the previous owner attempted repair or not.
If you look closed at the IC pins (in the photos I will post), it does appear that someone touched up or changed IC for left channel as one of the pins looks kind of dark to me.
Anyway, I resoldered the right channel two pins best I could. I made certain there is no short across the pins BUT when I powered back up, left channel is fine and right is still dead.
However, this time the right channel starts to get hot and after 2 min I powered down for fear it would overheat. It seemed to be just getting slowly hotter. I did not want to take a chance before I asked for an option from those who have experience.
Can someone please tell me what my next step should be?
I would appreciate the help.
Photos can be found here:
https://www.dropbox.com/sh/buaxlxajrv7ztc4/AAAISWMAtqXahMiRjjILt61ka?dl=0
More inspection. I see on the power board a capacitor that is suspicious looking at the base to me. Comments?
https://www.dropbox.com/s/q5yh7e67jshtpje/2015-08-20%2020.17.55.jpg?dl=0
https://www.dropbox.com/s/q5yh7e67jshtpje/2015-08-20%2020.17.55.jpg?dl=0
Ok I do not have a cap meter but will order one and a few caps and the op amp as well.
When the meter arrives I will test the cap and report results.
When the parts arrive, I will start replacing slowly and test along the way.
Should be a fun.
When the meter arrives I will test the cap and report results.
When the parts arrive, I will start replacing slowly and test along the way.
Should be a fun.
I am also wondering if I should just replace all the Caps on the power and Photo boards as I will be in there anyway and the parts are not expensive.
I see on the service manual's part list there are Electrolytic, Mylar and Ceramic caps.
Should I just replace the Electrolytic or all types?
What is your opinion?
I see on the service manual's part list there are Electrolytic, Mylar and Ceramic caps.
Should I just replace the Electrolytic or all types?
What is your opinion?
New caps is will rarely fix anything. Sounds like your ic there is shorted. Gonna need replacement.
A replacement HA-1457 arrived and I went ahead and replaced that.
The old unit appears to have a broken leg and looks burnt.
The Deox spray is still not here so I can't clean the input selector still but will do that as roger2 suggests.
After replacment of the IC the amp plays but still no right channel on Phono.
The HA-1457 does not get hot anymore however I notice that the two green diodes show in this pic get really hot.
The amp in Phono now has a loud hum; only in Phono.
I am thinking one of these is bad but am unsure how to test it.
Here is a pic of the area in question and you can see how burnt everything looks:
https://www.dropbox.com/s/ay77duj39w...37.32.jpg?dl=0
Here is the bottom of the board:
https://www.dropbox.com/sh/buaxlxajr...jjILt61ka?dl=0
Please suggest the next test or course of action.
Thanks!
The old unit appears to have a broken leg and looks burnt.
The Deox spray is still not here so I can't clean the input selector still but will do that as roger2 suggests.
After replacment of the IC the amp plays but still no right channel on Phono.
The HA-1457 does not get hot anymore however I notice that the two green diodes show in this pic get really hot.
The amp in Phono now has a loud hum; only in Phono.
I am thinking one of these is bad but am unsure how to test it.
Here is a pic of the area in question and you can see how burnt everything looks:
https://www.dropbox.com/s/ay77duj39w...37.32.jpg?dl=0
Here is the bottom of the board:
https://www.dropbox.com/sh/buaxlxajr...jjILt61ka?dl=0
Please suggest the next test or course of action.
Thanks!
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