Asking for help on a blown channel on Pioneer SA-510

[andy3055]

That is good news. To be safe, check the voltages on that transistor. The values are in the diagram. I think you must have gone through a cold joint and fixed it. There could be other similar issues given the age.

[Dan75]

Not sure how to do that. Measuring voltage on the transistor in circuit. Which MM mode should it be and where do you place the leads? And with the unit powered up?
Sorry, but that is where my know how ends

[CharlotteSwiss]

To have the voltages you will need to have the unit turned on: you can easily compare the voltages on the components, having as a reference the working channel, the components are mirrored

[andy3055]

Not sure how to do that. Measuring voltage on the transistor in circuit. Which MM mode should it be and where do you place the leads? And with the unit powered up?
Sorry, but that is where my know how ends

The voltages must be checked with power on. The older amps had a bottom plate that could be removed leaving everything open from the bottom. If not, you have to do it from the top. In either case, you must be careful not to slip the probe and short the legs of the transistor. The base voltage can be checked from the two ends of the Zener diode that connects to the transistor base. The emitter is easier as it goes out from the board - see point marked 1 inside the circle.

Put the negative lead of the meter on the ground connection or the point marked 9 (or 51) inside a circle and check the two voltages per the diagram. Just be careful not to blow anything!

[Dan75]

Up until now it has been working fine and realizing that I haven't had the best of luck recently I will leave as is now just because it seems to do its job.
I did replace some of the caps you had mentioned earlier, not all of them as I did not have every type needed.
Maybe indeed I jumped upon a cold solder somewhere or it's just a combination of the things that have been done.
So far, 

[Wallace Gasiewicz]

Years ago my SO's Kenwood receiver had a similar problem. I was looking at the board and the SO (who is to be obeyed) pushed on a screw and the unit came back to life.
Tightened the screw 15 years ago and still works. Bad ground probably.

[andy3055]

As long as it works without any issue, you can leave it and hope it will not come back!

[Jeff eelcr]

I do not remember the circuitry in that unit but static and pops can be a diode or transistor breaking down intermittantly usually it will be a TO92 type transistor (not always). Heat/cold can be used to isolate the defective part.  A scope at the amp input capacitor can tell you if its in the preamp or output section. Good luck.
Jeff