Yamaha R-500 Question

[oldtubes]

I have a Yamaha R-500 with a bad STK2040 module. The STK2040 is hard to find but I see the STK2240 is more common. Comparing the to chips on the internet the STK2240 looks like a STK2040 with internal emitter resistors. Has anyone tried to substitute the STK2240 for the STK2040 by removing the external emitter resistors?

 

[malanga]

I have a R-300 with a problem tuner section, but the rest appears to be okay. Does it use the same module as the 2030? If so let me know, perhaps we could work something out.

 

[oldtubes]

The STK2030 module requires less voltage than the STK2040. The R-500 has too high a supply voltage for the STK2030. Thanks anyway.
I studied the equivalent circuit diagrams for the STK2240/STK2040 modules and the amplifier circuit board trace. The pin layout is the same for both modules except for the output pin 4 and 13 are used in the 2240 module. The output pins 4 and 13 are unused on the circuit board and the output transistor emitter pins 3,5,12,14 on the STK2240 can use the external emitter resistors just like the STK2040. So it looks like a drop in. I plan on ordering one and give it try.

 

[srinath]

What happened ?

The STK2030 module requires less voltage than the STK2040. The R-500 has too high a supply voltage for the STK2030. Thanks anyway.
I studied the equivalent circuit diagrams for the STK2240/STK2040 modules and the amplifier circuit board trace. The pin layout is the same for both modules except for the output pin 4 and 13 are used in the 2240 module. The output pins 4 and 13 are unused on the circuit board and the output transistor emitter pins 3,5,12,14 on the STK2240 can use the external emitter resistors just like the STK2040. So it looks like a drop in. I plan on ordering one and give it try.

Hi, did you try this and did it work ?
I also have a dead 2040 in my yammie R-500. The other question I have, is there an NTE that will cross into it.
Thanks in advance.
Cool.
Srinath.

 

[srinath]

Fixed - sorta.

OK I pulled a chip out of another dead R500 that had a different issue and put it in this and have it working - sorta. I dont have left channel in the stereo mode. In mono mode, both channels work fine.
I am at a loss now. Anyone know what it could be.
Cool.
Srinath.