Re: Help diagnosing Pyle Receiver PTA66BT with burned resistors
OK, I soldered the 2W resistor in. With chips A-E & the power LED connected (F, G, and the CD IC disconnected), I read 6.23v across it.
I soldered back in the resistors to connect up chips F & G. With chips A-G & the power LED connected (CD IC disconnected) I read 7.66v across it. The VCC+ of chip F & G were around 5v each (A-E are ~10v)
I soldered back on the resistors and all the other components connecting the CD IC to the board, and read 11.70v across the new resistor. I took out my thermometer and the temp seems to stabilize at 137F-139F degrees. Certainly to hot to touch for more than a second, but I saw no white smoke and no burning resistor smell.
Now here is where I earn my idiot reward. I was checking the fan, and I disconnected it to the board and connected the ends to a 9v battery, and it spun. So I thought maybe somehting is wrong with the board not turning it on, how about I just wire it right to the main power supply going into the unit? Nothing bad could happen by dumping 120 AC into a small 12v DC fan, could it?
So yeah, now I need a new fan. And annoyingly its a 60mm fan and all I have on hand are 80mm fans, and even more annoyingly the unit is like 75mm tall so I can't fit an 80 in there as a replacement. Sigh
So I'm ordering a new 60mm fan, I don't want to run the unit for a long time without the cooling fan attached, so while it's back together I have not extensively tested it yet. When I get the new fan in and run it through it's paces I will let you know what happens.
OK, I soldered the 2W resistor in. With chips A-E & the power LED connected (F, G, and the CD IC disconnected), I read 6.23v across it.
I soldered back in the resistors to connect up chips F & G. With chips A-G & the power LED connected (CD IC disconnected) I read 7.66v across it. The VCC+ of chip F & G were around 5v each (A-E are ~10v)
I soldered back on the resistors and all the other components connecting the CD IC to the board, and read 11.70v across the new resistor. I took out my thermometer and the temp seems to stabilize at 137F-139F degrees. Certainly to hot to touch for more than a second, but I saw no white smoke and no burning resistor smell.
Now here is where I earn my idiot reward. I was checking the fan, and I disconnected it to the board and connected the ends to a 9v battery, and it spun. So I thought maybe somehting is wrong with the board not turning it on, how about I just wire it right to the main power supply going into the unit? Nothing bad could happen by dumping 120 AC into a small 12v DC fan, could it?
So yeah, now I need a new fan. And annoyingly its a 60mm fan and all I have on hand are 80mm fans, and even more annoyingly the unit is like 75mm tall so I can't fit an 80 in there as a replacement. Sigh
So I'm ordering a new 60mm fan, I don't want to run the unit for a long time without the cooling fan attached, so while it's back together I have not extensively tested it yet. When I get the new fan in and run it through it's paces I will let you know what happens.
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