Yamaha AX900 differential transitor subsistute?

[avionic]

For this application.

 

[absolve2525]

Well gosh, that's my bad! Lol I thought I read the diagram as them being reversed. I will remove them and test for damage. Thanks guys, I will update afterwards.

 

[restorer-john]

Japanese TO92 transistors come in various pinout combinations, the one in question is ECB across the flat front. ECB is the most common on Japanese TO92 variants, but don't assume it always is.

Toshiba, Hitachi use BEC sometimes, Sanyo used consecutive numbers with different pinouts as the only difference, to aid PCB manufacturers who may have already designed around a particular pinout and committed to PCB production.

 

[absolve2525]

Good news! I pulled the misdirected transistors and replaced them with correctly oriented matched pairs. With the pre-out main-in jumper pulled, I'm getting good DC offset readings. They fluctuate a little, but left channel is under 1mv and right channel is around 2mv. Much better! Things get a little weird with the jumpers installed, however. The numbers rapidly move up and down to 5mv. Not too bad... but when I hit the CD direct or mute buttons, the numbers go high and the relay clicks! Ummm something flaky is going on with the preamp part. I'm thinking I may just use it as an amp anyway, with a separate preamp, but it would be cool if I could figure out why it's acting weird. I cleaned the switches years ago, maybe it's related to that? Thanks for the help!