SX-737 AWG-030 Control Amp recommended replacement parts

[pa_200]

I pulled all caps and transistor on the AWG-030 board and that’s what I found.

C1 and 2 are special marked tantalum caps instead of the expected sky blue Sanyo 1µf 25V. The other caps like in the SM.
The transistor Q1+ Q2 are 2SA763, Q – Q6 are 2SC1312. The 2SC1312 are on the bad transistor list, but the 2SA763 are not.

Both sa763 are fine, but one of the sc1312 hat a hFe of 17 while all the others are between 585 and 600 hFe. Unfortunately, I cannot specify at which position the bad sc1312 was before.

Is it OK if I use as replacement SA992 for Q1+2 and KSC1845 for Q4-6 even with the lower hFe from the SA992, 390 hFe and the KSC1845 with 438 hFe?

And shall I keep the tantalum caps or use new 1µF 63V film caps?

 

[PTL-Pioneer]

In the searches that i have done it does seem that KSA992 replaces 2SA763
And that KSC1845 replaces 2SC1312

I think the 1845 and 992 partner are used as replacements quite a bit in tone control boards, especially the pioneer gear of this era

Id use the film caps to replace the tantalums, cannot see why it would be an issue, normally they are shoot on sight in this gear.

 

[EastPoint]

Yes, those transistors are fine. Replace the tantalums with the new film caps.

 

[pa_200]

Good, will replace as you recommend.

 

[EastPoint]

Just FYI, the KSC1845s will go in backwards compared to the 2SC1312s. The KSA992s will go in the same way as the 2SA763s. While the 2SA763s aren't on the "10 bad transistors" list, they do go bad sometimes, and I always replace them.