Working on a non-working Kenwood KA-4070 Need a sub for 2SA640E Semiconductor

[redpackman]

Correction. It's a Kenwood KR-4070. I don't know how to edit the title!!

Q1-Q4 semiconductors in the power amp section, are supposed to be either 2SA640E or F or 2SA841 (GR or BL) according to the Kenwood repair manual and specs. The previous owner has installed PN4249 even though the leg order is different between the two and has not installed them correctly. The 640's are ECB and according to the data sheets I have seen the 4249's are EBC, thus the E legs are in the right place but the B and C are reversed.

1. Please correct me if I'm wrong.

2. What would be a good sub transistor for the 2SA640E since they are now obsolete?

The receiver is not working. No wonder, I'd say.

 

[spark1]

I think KSA992s would be suitable subs for the 640s, and I believe they have the same pinout.

 

[Watthour]

Agreed about the 992s, and try to match the gain between the pairs. Lead orientation should not be a problem since reorienting the legs is so easy. The critical part is knowing when the pinouts are different.