Kenwood KA-3500 distortion left channel only! Guidance needed.

There is no voltage drop across 45,47. On the working right channel I get 16mv on both. 20mv once left on for a little bit.
 
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I'm at a loss checked orientation on transistors

qe1-4 2sa620wn > ksa992fbu
qe5,6 2sc1885 > ksc2383yta
qe7,8 2sa620wb > ksa992fbu
qe9,10 2sa733 > ksa733cyta
qe11-14 2sc945 > ksc945cyta
qe15,16 2sa733 > ksa733cyta
qe17,18 2sc1735 > ksc2690ays
qe19,20 2sa850 > ksa1220ays
qe25, 27 2sa673 > ksa1220ays
qe26 2sc1222 > ksc1845

I copied this list for most of my substitutions btw
 
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qe17,18 2sc1735 > ksc2690ays
Can you check, I have 2sc1735 as bce and KSC2690 as ecb

qe19,20 2sa850 > ksa1220ays
likewise

I assume that you have simply rotated these transistors.

I keep coming back to the low current flow down Re27, VRe1,,, ie, higher than expected resistance in this path.
THe1 measured at 11k, suggest do same measurement on other side/channel
 
Found it! The foil print on the bottom of the board is wrong the hole labeled B for q17 should be E it's tied directly to the base of q21. About to make the switch as soon as the solder gun warms up.
 
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Finally success! Let this be a warning don't trust the markings on the ka-3500 power amp board or any board for that matter. Follow the traces and double check :)

Now onto recapping the pre amp section and since I have an over supply of transistors should I just finish restoring the right channel and pre amp section or just leave it be?

Need to recheck bias and dc offset after a good warm up but it sounds really good at the moment. Any tips for lowering dc offset? Last time I checked they were in the 30mv range for both channels.
 
Thanks again mbz.

So finally gave it a good warm up and reset bias. I set it to around 18mV warm because if played loud right before checking bias it would zip up to about 20mV. DC offset is between -35-37mv on both channels.
 
James here: I just acquired a KA-3500 off of craigslist from a guy who said it worked fine. He was selling a package deal with the amp, a tuner and some speakers. He said the speakers (which I did not really want) were a bit scratchy. Well, it was the amp, I am getting distortion out of both outputs that is volume related. I suspect power transistors. I have done several amp repairs but may need some help on this one.

Wish me luck!
 
I have one that is currently getting full recap/repaired, but we have had some trouble matching new power transistors. The old ones were OK, but had mismatched DC offset (low in left, but about 55 mV in right) and that was causing a noticeable sound difference... Let me know if you have any light to shed, jm, re your restoration work. It's a lovely amp, really hoping to find a solution re the transistors.
 
Hello J,

I will be diving into this little puppy in the next week or two. I have an old Akai M8 tube amp I am converting to a guitar amp first. Nearly done there. I imagine I will have struggles finding the right transistors and such. A while ago I repaired a Nikko NA-850 that gave me a run for the money but it was worth it in the end. I too love these KA-3500 amps.
 
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