Harolda
Well-Known Member
I am looking at a defect TA-N7B. Before starting to work on it i first want to check the status of the V-fets. I have worked on these units before, but they where in full working order when i received them.
I tried to find a procedure to check these devices. I found some on AK, mainly for 2sk18 and 2sk60 for other Sony amps like TA-4650, -5650 etc. But i guess the procedure is the same.
So what i did
1) Resistance measurement between S - D (Source - Drain)
all measure between 1.5 - 2.1 Ohms
2) Diode test (+/- and -/+):
S - G all measure around 0.5V
D - F all measure around 0.5V
I attached some pictures of how i used to Multimeter to perform these measurements. Is this correct, and if so can i conclude that the devices are OK?
I also did some first voltage checks on the amp (without the V-fets). I have a service manual, but it is a scan and it is difficult to read the exact voltage requirements. What i found thus far is that at some point where the manual indicates 0V, i get ~45V. I will post more data on the voltage measurements, but it would be helpful if someone has a better scan of the service manual.
thanks in advance for your advise.
I tried to find a procedure to check these devices. I found some on AK, mainly for 2sk18 and 2sk60 for other Sony amps like TA-4650, -5650 etc. But i guess the procedure is the same.
So what i did
1) Resistance measurement between S - D (Source - Drain)
all measure between 1.5 - 2.1 Ohms
2) Diode test (+/- and -/+):
S - G all measure around 0.5V
D - F all measure around 0.5V
I attached some pictures of how i used to Multimeter to perform these measurements. Is this correct, and if so can i conclude that the devices are OK?
I also did some first voltage checks on the amp (without the V-fets). I have a service manual, but it is a scan and it is difficult to read the exact voltage requirements. What i found thus far is that at some point where the manual indicates 0V, i get ~45V. I will post more data on the voltage measurements, but it would be helpful if someone has a better scan of the service manual.
thanks in advance for your advise.