I have a Sony TA-F570es that wont come out of protection. It has been fully recapped of all electrolytics and most of the mylar film caps. It had been working fine and one day it got very warm and went into protection.
I checked the bias and left channel reads 0 vdc and right reads -47 mv and going up. Looking at the schematics I am not sure where to check my rail voltages. A little help would be appreciated.
Phik
I checked the bias and left channel reads 0 vdc and right reads -47 mv and going up. Looking at the schematics I am not sure where to check my rail voltages. A little help would be appreciated.
Phik
All voltages that are expected are in the schematic.
Rails are B+ and B-.
Look at your circuit, main smothing capacitor are my point for measuring.
It will not come out of protection, if the output from either amplifier has any DC voltage on it or it is drawing excessive current.
Strange how the 'go to' repair is always "Change the capacitors" with the DIY sector. It rarely cures anything.
Rails are B+ and B-.
Look at your circuit, main smothing capacitor are my point for measuring.
It will not come out of protection, if the output from either amplifier has any DC voltage on it or it is drawing excessive current.
Strange how the 'go to' repair is always "Change the capacitors" with the DIY sector. It rarely cures anything.
I will get on that this evening. 105 degrees here today and my office is upstairs without a functioning AC so I wont be going up there during sunlight hours.
Agree on the capacitor swaps. Most of the repairs I have done with the help of some techs on here the problems were usually bad resistors or diodes.
Agree on the capacitor swaps. Most of the repairs I have done with the help of some techs on here the problems were usually bad resistors or diodes.
OK rail voltages are 33.2 vdc and -34.5 vdc.
Output Transistors
Q312 B-,6vdc C-34.2vdc E-.05
Q313 B-.6vdc C- -34vdc E- .05vdc
Q309 bias E-.9vdc C-0 E-0
Q362 B- -20 C-0 E- -21vdc
Q363 B-34 C-0 E- -22vdc
Q359 bias E -34vdc C- 0 B- -33vdc
It looks like I have rail voltage o the left channel output transistors
Thats all i could take the heat in my room I need to get this room ac replaced. I will start taking measurments back towards the source.
Output Transistors
Q312 B-,6vdc C-34.2vdc E-.05
Q313 B-.6vdc C- -34vdc E- .05vdc
Q309 bias E-.9vdc C-0 E-0
Q362 B- -20 C-0 E- -21vdc
Q363 B-34 C-0 E- -22vdc
Q359 bias E -34vdc C- 0 B- -33vdc
It looks like I have rail voltage o the left channel output transistors
Thats all i could take the heat in my room I need to get this room ac replaced. I will start taking measurments back towards the source.
one other thing about this amp it is 220v. I have it plugged into a stepup transformer which is plugged into my DBT. I hope this will help keep it in a safe state. The bulb does dim to a certain degree . Any thoughts if this will work
So now further testing revealed Both output transistors Q312 and Q313 tested bad. 2SA1215 and 2SC2921. the bias trasistor o the other channel is bad as well, 2SC3423.\
I noticed on ebay there is some used ones but not sure if they are the real deal The bias transistor might be replaceable with
2SC2690.
I noticed on ebay there is some used ones but not sure if they are the real deal The bias transistor might be replaceable with
2SC2690.
I have these, brand new. However, I'm in the UK which may make postage prohibitive.
If you are stuck, and want them, I'd be happy to send them to you for just the cost of postage.