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SX-D5000 bias/idle current adjustment

I didn't have the black lead on a bare part of the chassis which was problem number one. Got a new voltmeter and it appears the other one was not reading properly. I am getting sound out of the receiver and it sounds great. Here are the readings with the new meter and hopefully they make more sense:


Transistor One: Brown wire- 052.3v, Orange Wire- 000.8v, Red Wire- 000.4v
Transistor Two: Brown wire- 052.3v, Orange Wire- 000.7v, Red Wire- 000.1v
Transistor Three: Brown wire- 052.0v, Orange Wire- 000.4v, Red Wire- 000.0v (25mV)
Transistor Four: Brown wire- 052.0v, Orange Wire- 000.5v, Red Wire- 000.0v (42mV)
 
mea2112 said:
I didn't have the black lead on a bare part of the chassis which was problem number one. Got a new voltmeter and it appears the other one was not reading properly. I am getting sound out of the receiver and it sounds great. Here are the readings with the new meter and hopefully they make more sense:


Transistor One: Brown wire- 052.3v, Orange Wire- 000.8v, Red Wire- 000.4v
Transistor Two: Brown wire- 052.3v, Orange Wire- 000.7v, Red Wire- 000.1v
Transistor Three: Brown wire- 052.0v, Orange Wire- 000.4v, Red Wire- 000.0v (25mV)
Transistor Four: Brown wire- 052.0v, Orange Wire- 000.5v, Red Wire- 000.0v (42mV)
Click to expand...

Getting there.... I sorta miss reading the polarity of the voltage... it's an old friend :D

Try re-reading the idle current & offset voltages for each channel with the new meter, also is the heatsink getting really hot?
 
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Checked the DC offset again and one channel was at 38mV and the other was at 90mV. Got those adjusted close to 0. Checked the idle current again and sure enough it was way off too. Got each channel to between 147mV and 151mV. The heatsinks are quite a bit cooler now. They're still pretty warm to the touch but not to the point where you have to pull your hand away. I can actually touch them now. Hopefully, this receiver is in good shape now and no damage was done.
Never would have thought my original voltmeter was bad. The new one is a big improvement. I'll never buy a cheap meter again!
 
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