Output Transistor Different than Service Manual - Onkyo TX-4500 mkii

[curtisw99]

I'm trying to get this Onkyo Tx-4500 (just acquired, non-working) out of protection, so first place I went was to test the outputs.

They measure good, but they do not match the transistors in the manual.
are these the wrong transistors, or are they equivalent to the ones in the manual.

Receiver has two 2SB681 and two 2SD551 installed

Manual calls out two 2SA747 and two 2SC1115

Is this an issue?

 

[Lavane]

Do they look like they were factory installed?
Sometimes that make changes along the way and manufactures rarely update the schematics.

 

[curtisw99]

Do they look like they were factory installed?
Sometimes that make changes along the way and manufactures rarely update the schematics.

can't tell, the grease has turned to powder and they may or may not have been replaced

 

[Lavane]

I guess you could oook at the data sheets and see if they're compatible with what's on the schematic.

 

[hamrules]

Should be good.

 

[Tom B]

you are fine with the two 2SB681 and two 2SD551 installed, as long as they read OK

 

[sregor]

Parts list shows B681 and D551 for USA version, C1116 and A747 for universal version. Functionally they are nearly the same.
The B681 and the D551 are in the second schematic in the manual.

 

[curtisw99]

Parts list shows B681 and D551 for USA version, C1116 and A747 for universal version. Functionally they are nearly the same.
The B681 and the D551 are in the second schematic in the manual.

View attachment 3413993

Missed that, was reading universal

 

[petes'picks]

I think the 2sc1116 were discontinued right about the time the TX-4500ii were being made. I dont recall ever seeing them being used in products after that time frame. They likely just made a change during that products run.