Recent content by Longhorn262

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.

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...

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.

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 >...

Hooking up speakers just for fun get loud clean music out of the right and left channel sounds fine until half volume

Qe7 voltages 5.3, 3.1, 4.7vdc

1.3mv volume all the way up. Playing a sign wave all voltages on the schematic look good until collector q5 it's 3v dc.

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.

Just measured re27,25,23 only one out of spec was 25 at 1.5k vs 1.8k Ve1 was 40ohm to 1k ohm appears to be fine BTW the1 is 11k when I disconnected the other day

Perfect I'll start here and report back

I'm about to systematically pull inspect and replace every component in the left channel. I've even inspected diode 13 14 7 and 9 all check out with my tester. Even the transistors I pulled and replaced were all good except q17 19 21 and 23. First I just replaced 21 and 23 and that got rid of...

Weird thing is I get a clean output on the speaker terminals at 18v. Only switches that effect base of q19 and q17 is the tape rec switches.

Hav Have not tried that yet but I cannot adjust bias at all and base of q19 and q17 are up near 20v at full volume. All electrolytic caps and all transistors. And power resistors.

So it's not caps or transistors. Has to be a diode or resistor somewhere. :(

Just replaced every transistor on the left channel plus q26 and q27 and base of q19 and q17 are still not +-1.2v in fact they are in the 20v range