# Sony TA-FE230 Amplifier 120W

#### LesJones

Joined Jan 8, 2017
3,953
Can you measure the following voltages.
C306 +
C306 -
C356 +
C356 -
Both sides of R305
Both sides of R306
Both sides of R355
Both sides of R356
Both sides of R307
Edit Also
Both sides of C353
Both sides of C303
Both sides of R353
Both sides of R303
Les.

Last edited:

#### spike1947

Joined Feb 4, 2016
484
Can you measure the following voltages.
C306 +
C306 -
C356 +
C356 -
Both sides of R305
Both sides of R306
Both sides of R355
Both sides of R356
Both sides of R307

Les.
Ok will do.
Tks
Spike

#### spike1947

Joined Feb 4, 2016
484
Ok will do.
Tks
Spike
Can you measure the following voltages.

C306 + = 0v

C306 - = 43v

C356 + = 32.3v

C356 - = 39.1v

Both sides of R305 = 42v and 39v

Both sides of R306 = 41.8v and 44.7v

Both sides of R355 = 39.2v and 44.7v

Both sides of R356 = 44.7 and 44.8v

Both sides of R307 = 44.9v and 45.8v

Edit Also

Both sides of C353 = 26.4v and 26.3v

Both sides of C303 = 26.2v and 26.4v

Both sides of R353 = 26.3v and 26.4v

Both sides of R303 = 26.3v and 26.4v

Cheers
Spike

#### LesJones

Joined Jan 8, 2017
3,953
The readings from post #103 look reasonable but the offset on the top half (Right channeL ) have changed polarity since the readings from post #63.
Can you measure the voltage on both ends of R320.
Can you then remove power to the amplifier and give the capacitors time to discharge then measure the resistance between the ends of R320. Then measure the resistance between IC301 pin 5 and each end of R320.
Les.

#### spike1947

Joined Feb 4, 2016
484
The readings from post #103 look reasonable but the offset on the top half (Right channeL ) have changed polarity since the readings from post #63.
Can you measure the voltage on both ends of R320.
Can you then remove power to the amplifier and give the capacitors time to discharge then measure the resistance between the ends of R320. Then measure the resistance between IC301 pin 5 and each end of R320.
Les.
Ok
Will do
Tk
Spike

#### spike1947

Joined Feb 4, 2016
484
The readings from post #103 look reasonable but the offset on the top half (Right channeL ) have changed polarity since the readings from post #63.
Can you measure the voltage on both ends of R320.
Can you then remove power to the amplifier and give the capacitors time to discharge then measure the resistance between the ends of R320. Then measure the resistance between IC301 pin 5 and each end of R320.
Les.
Can you measure the voltage on both ends of R320 = 0v and 10mv.

Can you then remove power to the amplifier and give the capacitors time to discharge then measure the resistance between the ends of R320 = 2.3π
Then measure the resistance between IC301 pin 5 and each end of R320 = 2.3π and 0π
Thanks
Cheers
Spike

#### LesJones

Joined Jan 8, 2017
3,953
That is exactly how it should be. It was because I noticed that you measured -10 volts on one end of R320 in the results that you posted in post #63.

Les.

#### spike1947

Joined Feb 4, 2016
484
That is exactly how it should be. It was because I noticed that you measured -10 volts on one end of R320 in the results that you posted in post #63.

Les.
Hi Les
That sounds good !.
Tks
Spike

#### MisterBill2

Joined Jan 23, 2018
14,280
If anything has changed especially polarity, I would suspect something is intermittent. Or was it just an error in notation??

#### LesJones

Joined Jan 8, 2017
3,953
Spike, Can you do the following tests.
Remove C356 and test it's leakage current with about 25 - 30 volts applied. (Make sure you have the polarity correct.) Also use a current limiting resistor to avoid the risk of damaging the meter that you use to measure the current. Measure the actual resistance of R355 and R356. You will have to disconnect one end of each resistor to get a correct reading.
This is the reason for the test. These 2 resistors are in series and have the same value so the voltage across each resistor should be the same. The only thing connected to the junction of these resistors is C356 and no DC current should pass through this.

Les.

#### spike1947

Joined Feb 4, 2016
484
Spike, Can you do the following tests.
Remove C356 and test it's leakage current with about 25 - 30 volts applied. (Make sure you have the polarity correct.) Also use a current limiting resistor to avoid the risk of damaging the meter that you use to measure the current. Measure the actual resistance of R355 and R356. You will have to disconnect one end of each resistor to get a correct reading.
This is the reason for the test. These 2 resistors are in series and have the same value so the voltage across each resistor should be the same. The only thing connected to the junction of these resistors is C356 and no DC current should pass through this.

Les.
Hi Les
Ok will do.
Tks
Spike

#### spike1947

Joined Feb 4, 2016
484
Spike, Can you do the following tests.
Remove C356 and test it's leakage current with about 25 - 30 volts applied. (Make sure you have the polarity correct.) Also use a current limiting resistor to avoid the risk of damaging the meter that you use to measure the current. Measure the actual resistance of R355 and R356. You will have to disconnect one end of each resistor to get a correct reading.
This is the reason for the test. These 2 resistors are in series and have the same value so the voltage across each resistor should be the same. The only thing connected to the junction of these resistors is C356 and no DC current should pass through this.

Les.
Remove C356 and test it's leakage current with about 25 - 30 volts applied. (Make sure you have the polarity correct.) Also use a current limiting resistor to avoid the risk of damaging the meter that you use to measure the current.

Charged @ 27v, current = 1.5mA

Measure the actual resistance of R355: = 3.28 kΩ and R356: = 3.28KΩ.

cheers and tks
Spike

Last edited:

#### LesJones

Joined Jan 8, 2017
3,953
So the resistors are OK but the capacitor needs replacing. If you use one that you have had in stock for a long time or salvaged from some other device then check it's leakage first.

Les.

#### spike1947

Joined Feb 4, 2016
484
So the resistors are OK but the capacitor needs replacing. If you use one that you have had in stock for a long time or salvaged from some other device then check it's leakage first.

Les.
Ok Les
Tks for that .
Cheers
Spike

#### spike1947

Joined Feb 4, 2016
484
So the resistors are OK but the capacitor needs replacing. If you use one that you have had in stock for a long time or salvaged from some other device then check it's leakage first.

Les.
Hi Les
What sort of current reading should a good Cap give ?.

cheers
Spike

#### LesJones

Joined Jan 8, 2017
3,953
I don't know if there is a specification for leakage current but I tested 330 uf 50 volt one and it's leakage was about 10 uA. This was not a new one it is one I removed from something else.
This may not be related to the fault we are trying to fix.

Les.

#### spike1947

Joined Feb 4, 2016
484
I don't know if there is a specification for leakage current but I tested 330 uf 50 volt one and it's leakage was about 10 uA. This was not a new one it is one I removed from something else.
This may not be related to the fault we are trying to fix.

Les.
Hi
Only asked because I have 3 more of the same 47uf 25v, and they all seem to test the same and all hold a charge quite well, including the one I have taken out !.

cheers
Spike

#### LesJones

Joined Jan 8, 2017
3,953
According to the manual C356 should be 50 volts rating.

Les.

#### spike1947

Joined Feb 4, 2016
484
According to the manual C356 should be 50 volts rating.

Les.
Yes sorry, it is 50v.

cheers
Spike