Pioneer SA-6500II Balance issue

I finished repair of SA-6500 II. It was in really bad condition. I cleaned it carefully, deoxit all the switches/pot meters. Replaced all capacitors and transistors in amplifier section, first stage (2SD667; 2SB647) and second stage (MJE15033G;15032G) and now sounds very nice!! .
My only point is that left channel plays little louder then right channel with balance in mid position. Of course i can calibrate that with balance knob and add just a little more to right side, but I wonder what could be the reason??

hard to say (thought I posted on this MUCH earlier today, but... nothing's here)

resistive switch, overlooked old cap, low gain original transistor still in circuit....

try a quick shorting of pins 15 & 16 which are the volume control taps and see if the balance gets better - if so it's incoming signal and switches.

Also try tone on and off, see if that makes a difference.

To do mono at the amp inputs to see if they are amplifying differently, the place to connect them together is with tone off, the center post of the switch, channels are opposite sides of switch about 4mm apart. That is a circuit point where the different signals won't fight, just integrate.

You could try new
q3, q4 2sa640 > 512-KSA992FBU (ln)to-92 ecb 120v .05a .5w 100mhz 300-600hfe
q5, q6 2sc1222 > 512-KSC1845FTA (ln)to-92 ecb 120v .05a .5w 100mhz 300-600hfe
IF the mono at the volume control corrects nothing, but the mono at the tone control switch does correct the imbalance...

That points at those transistors and the tone controls.

Hi again markthefixer
I tried quick shorting pins 15-16 and the problem was gone, i.e. both channels in ballance (tone control off, loudness off). I've checked the volume VR and noticed different resistance on left and right channels with the same position of the shaft. For example 14kohm and 21kohm. The difference in resistance was bigger with lower volume and decreased with increase of volume (what I also observed with the sound, the more loud the less difference)....I tried to clean it some more but it did not help. So I hope the problem is there...

I replaced VR of volume and now everything sounds perfect
Now I only need new case and amplifier will be ready to be put on the shelf.
Thanks markthefixer for your advices !!.