So working on an SX-550 with low right channel volume and made a rookie mistake, didn't check balance function before I cleaned and recapped, so I don’t know if the issue was existing. All pots and switches have been cleaned multiple times with Deoxit. I took the input selector and power/speaker selector switches off of the board so I could get to both sides, and disassembled and cleaned the power switch contacts. (PS - I only have general electronics training (1986) and primarily on 8080 PC circuit boards, so I am rusty and new to audio circuits). Check most all TP voltages. So I started comparing left and right channel voltages through the circuit paths (assuming I am following the schematics properly). Speaker outputs: L 16mV, R 21mV. All voltages on AF Muting board were correct. Got to the Tone Amp and find voltages in the right channel significantly off. So I am asking for some direction on where to look from here. Below are the voltages. Prior to this testing, the electrolytics were all replaced with Nichicon and Wima. I verified values and polarity. I had replaced Q14, Q15, Q16 and Q17 and found I had Q17 mis-oriented, so I had to remove it and resolder - not sure if I might have damaged it? Q14 and Q15 are 992's and Q16 and Q17 are 1845's (all parts were from a kit I ordered from Marblehead Audio). I should have some more 992's and 1845's here today, so I can replace if needed. Appreciate any guidance.
Update - Q15 and Q17 both tested good with DMM. I measured voltage at base of Q14 = 0.035v; at base of Q15 = -6.95v.
Update 2 - compared resistance of R and L pots on the volume and values matched throughout the range. On the balance, at center detent, I had continuity through to both channels.
Update - Q15 and Q17 both tested good with DMM. I measured voltage at base of Q14 = 0.035v; at base of Q15 = -6.95v.
Update 2 - compared resistance of R and L pots on the volume and values matched throughout the range. On the balance, at center detent, I had continuity through to both channels.
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