There’re several Pioneer amplifiers that carry two MOSFET pairs IRF530 / IRF9530 from International Rectifier:
A-107
A-109
A-207
A-209R
A-307R
...and others
Well, two years ago I bought 10 pairs of these transistors at AliExpress. Although I was very aware of counterfeits, I thought that a quite humble and inexpensive MOSFET wouldn’t be attractive to counterfeiters.
They looked fine and I’ve used them as replacements, with very deceiving results. At first, they apparently work fine, but soon I noticed some disturbing differences. Heatsinks at repaired channel were almost cold when compared to the original channel!! And when I tried to adjust Idle Current (according to Service Manual) it was impossible. It reads 0V regardless of potentiometer position and it becomes unstable when rising volume. In normal conditions it can be adjusted to about 10mV.
Eventually, all repairs returned after some time with replaced transistors blown again.
This time I ordered Siliconix / Vishay versions and these ones have worked like a charm. Same heating and expected response to idle current adjustment.
So, beware of fakes at any popular component. Or better buy modern equivalents instead of exactly the same original brand/part, because those are main targets for counterfeiters.
A-107
A-109
A-207
A-209R
A-307R
...and others
Well, two years ago I bought 10 pairs of these transistors at AliExpress. Although I was very aware of counterfeits, I thought that a quite humble and inexpensive MOSFET wouldn’t be attractive to counterfeiters.
They looked fine and I’ve used them as replacements, with very deceiving results. At first, they apparently work fine, but soon I noticed some disturbing differences. Heatsinks at repaired channel were almost cold when compared to the original channel!! And when I tried to adjust Idle Current (according to Service Manual) it was impossible. It reads 0V regardless of potentiometer position and it becomes unstable when rising volume. In normal conditions it can be adjusted to about 10mV.
Eventually, all repairs returned after some time with replaced transistors blown again.
This time I ordered Siliconix / Vishay versions and these ones have worked like a charm. Same heating and expected response to idle current adjustment.
So, beware of fakes at any popular component. Or better buy modern equivalents instead of exactly the same original brand/part, because those are main targets for counterfeiters.
Comment