2226B Balance Knob Issues

[dankik]

First, just to be positive the issue is in the main amplifier circuit, and not in the preamp / tone circuit, use a stereo patch cord to jump left to right and right to left in the preamp / main amp jacks on the back (I did not see in the previous posts where this was done).

@AE Bob, he did (see post #7 & 8 ).

 

[Houjuu]

Okay new update again! Did some more part replacing and have in total replaced 12 components, those being capacitors C701-C706, transistors Q701-Q704, and transistors Q741 and Q743. I replaced these because I believed them to be faulty after testing all with a DMM. Good news: the receiver still turns on and functions exactly as it did at the beginning of all of this. Bad news: it still functions the exact same...

I did get some new info though. I tested what would happen to the balance if I turned the volume to the absolute maximum. I plugged in my phone and made the source's volume very low so I didn't explode the speakers I was testing on. Turns out, when the volume is at the VERY loudest and nothing below that, balance seems to work? Any advice on where to go from here? I could replace some more transistors, but I'm not sure which matter anymore.

 

[dankik]

Turns out, when the volume is at the VERY loudest and nothing below that, balance seems to work?

This does not make any sense. In Post #8 you cross-connected the Pre-Out L to Main In R and Pre-Out R to Main In L and you said that the L channel was more powerful than the R channel, which is the same as when you had it connected L to L & R to R. This would point to the problem being in the Main Amp and not the PreAmp.

Tried this and luckily the same results occurred with the left channel being more powerful than the right.

But, now you are saying that IF you turn the volume control all of the way up (while reducing the input signal level to prevent overly loudspeaker output), then the balance control works fine, you get equal sound levels from both channels, and can adjust the balance correctly.

The Balance and Volume controls are electrically BEFORE the tone controls (PE01 board) and before the Pre-Out/Main In jumpers and P700 Main Amp board. So, if you increase the volume control while reducing the input signal level it should present the same voltage levels as input to the Main Amp board. This means that the problem is NOT in the Main Amp, but in the PreAmp, volume, or balance controls and that your previous test results of swapping Pre-Out and Main In was not done correctly?

Please double check your results for that test. To help isolate the problem (again) to the Main Amp vs Preamp, use you phone or other audio signal source (from another preamp) with variable output level control, and connect it to the L/R Main In RCA jacks. Turn the volume way down. Turn on the 2226B and listen (you will not control the volume using the 2226B volume control). Are the speaker output volume levels the same now? You can vary the volume up/down to verify that it is/isn't a Main Amp issue.

 

[Houjuu]

Alright, gonna put this project on pause for a bit, I'm going mad having dreams about changing caps and transistors. I apologize for my inadequacy to properly describe and test things that members here have asked; this is my first time doing anything this in depth with a receiver before. Thank you dankik and AE Bob so much for your help and understanding. Someday the 2226B will rise again, and with it your names shall it honor.

 

[dankik]

Let us know when you want to resume, we'll be here.