Meaning of codes on two transistors.

This is my first post.

I have a Marantz PM-66SE KI.

The left speaker and headphone outputs are almost completely silent. This might be due to dead transistors.

I opened the unit and I noted the codes on the transistors screwed onto the heat sink. They are


and


I understand if I see a part code with a 2S in front then it is the Japanese version of the code.

But what do the R 7K and R 8A mean? How do I know if I am buying the right replacement part?

Are there alternatives that are equivalent or better?

BoBble said:

This is my first post.

I have a Marantz PM-66SE KI.

The left speaker and headphone outputs are almost completely silent. This might be due to dead transistors.

I opened the unit and I noted the codes on the transistors screwed onto the heat sink. They are

Code:

A1265N
R   7K

and

Code:

C3182N
R   8A

I understand if I see a part code with a 2S in front then it is the Japanese version of the code.

Click to expand...

The 2S isn't generally printed - you simply need to add 2S to those numbers (2SA1265N and 2SC3182N).

But what do the R 7K and R 8A mean? How do I know if I am buying the right replacement part?

Click to expand...

They might be date codes perhaps?, but they don't matter.

Of MUCH more importance is the fact that it's very rare to repair an amplifier by just changing the output transistors, you need to change anything else that is damaged, and whatever actually caused the problem in the first place - it's like a row of dominoes - something small causes damage further on.