Sansui AU-5900 Help Needed

[zelgy1]

Hi all! I am completing a few upgrades on a Sansui AU-5900. Before I started any work, I did test the unit and only had a slight hiss that I was trying to address. I have replaced all transistors on F-2604 Tone Board with KSC1845F's. I also replaced the fuse resistors R31,R32, R41, and R42 on F-2596 Power Amp Board with 1/4 W 220 ohm metal film resistors. The issue I am currently finding is terrible snapping/popping sound in both channels, but primarily the left channel. Adjusting volume doesn't affect it. I have visually inspected all solder joints and ensured there are no shorts that were created when I soldered in new components. Before I move forward with anything, I am questioning my replacement transistors KSC1845F's in place of the 2SC1313's on the tone board. I'm finding the KSC1845, non-F, is the recommended replacement. Would this cause the popping sound or does it sound more like a bad solder joint? All replacement parts were purchased from Mouser and tested before install. As always, I greatly appreciate any feedback!!

 

[Leestereo]

Has the input differential pair 2SA798 (IC1 and IC2) been replaced?

 

[zelgy1]

Has the input differential pair 2SA798 (IC1 and IC2) been replaced?

I have not replaced the IC1 and IC2.
Quick update: I did hit the solder joints again on the tone board transistors that I replaced. Appears to have taken care of the popping. I am now left with slight crackle sound, but is covered by the music when played. However, I do think there is more improvement to be had to eliminate the noise. I will focus on IC1 and IC2 next. I'm questioning replacement of the other C1313's on the Equalizer board. To me is sounds like noisy transistors. If there are other points of focus, please let me know.