Pioneer SX-950 wont come out of protection

[CavScout]

So black lead on the negative side of the cap and red on positive?

 

[Watthour]

That is the conventional method. However, if a DMM is connected just opposite the way you describe, if would display a negative voltage indication.

 

[CavScout]

fuse 2 and 3 ac voltages ?
if they are good we need to start looking at q1 collector voltage . its late here so will be gone for a while .. sure others will guide you if watching ..
pin 14 voltage needs checking too now i looked some more ..

I don't know how to test Q1 .
That is a transistor right.
Please let me know how

Pin 14 is reading negative 51.4 v dc

 

[petehall347]

ok you need to find out where q1 is .. or measure capacitor voltages that were mentioned earlier . be worth checking solder joints to rule those out .. always my first call

 

[CavScout]

The AC voltage levels appear to be normal. Locate the medium-sized electrolytic capacitors C10 and C11. Check the DC voltages at each of those. Expect about 60VDC across each one.

C10 was 63.7 v DC
C11 was 64.2 v DC

 

[petehall347]

q1 then . check solder first

 

[CavScout]

ok you need to find out where q1 is .. or measure capacitor voltages that were mentioned earlier . be worth checking solder joints to rule those out .. always my first call

Which solder joints ?
What am I looking for ? Cracks ?

 

[petehall347]

yes power board . dark ring .

 

[CavScout]

I am assuming that you mean that I am looking for cracks (looking for dark rings as evidence?)

 

[CavScout]

I have found Q1

It looks like it is a bitch to get to

 

[CavScout]

Should I pull the heat sink ?

 

[CavScout]

Is it possible that it is just a bad speaker relay ?

 

[petehall347]

no its not the relay .. its the regulated power supply with the problem

 

[zebulon1]

On the 950 the TO-220’s will develop loose/cold solder connections. It might only need to be reflowed?

 

[CavScout]

What/where are the TO-220's ?

 

[petehall347]

power supply board .

 

[petehall347]

 

[CavScout]

So TO-220 is the nomenclature of the power supply board or just that one part (transistor?)

 

[petehall347]

its the transistor case style id .

 

[CavScout]

I reflowed those. No change, not sure what to do now