Pioneer SA-9800 - what to do?

Okay, my mistake. Fitted Q2 backwards... Well, now the voltage are just fine unloaded.
Connected the 52v to the amplifier and it's still correct.
Then i fitted the 32v to the Equalizer and the voltages went crazy. -11 and 71v. How can this be?

Any suggestions or should i just test everything on the equalizer board?
 
disconnect the eq board and see if the +/- 52v is still ok. If not,

pull the pre-out / amp-in jumpers and try the 32v again, then we will know if it's a power draw or signal line problem.

If it doesn't do it with the jacks out, measure the DC output voltage at the pre-out jacks.
-------do this or skip ---------
The only regulated voltages the power amps use are +/- 52v.

Check for a reversed c46 (47uf 50v) on the eq board. C32 (47uf 35v) on the control amp
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If it does it with the jacks out, then re-measure the power supply voltages, a huge load on the +32v affects the zener voltage on the +52v line, although the -52v line is supposed to track the +52v line.
 
Everything is fitted like it should since it worked fine for many hours until it just stopped.

The 52 voltages are fine with and without the eq connected.

The pre outs has no dc.

The only voltage that is affected by the eq is the -32. With it connected it will stay at -12.5v while rest of the voltages are unaffected.

Todays results are this without the -32 connected to the eq (correct value):
1,2 -53v (-52)
3,4 53v (52)
5,6 32v (32)
7 18v (18)
9 -68v (-48)
10, 11 -32v (-32)
12 34v (50)
13 68v (68)
15 -73v (-68)
 
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pin 9 is the -32v supply being dropped to -48v from -68v By a 220 ohm 5 wat resistor

20 volts across 220 ohms 5 watts is about 91 mA

what is the voltage across pin 15 to pin 9 when the -32v is -12v ?

too much of an overload and the resistor strangles the regulator.

since the -32v comes out on pins 10 and 11, is it pin 10 or pin 11 that is connected and causes the drop?

pin 10 should be drawing 60 milliamps (GWF-116 equalizer, C45 47uf 50v) ,
and
pin 11 should be drawing 16 milliamps (GWG-124 control amp C31 47uf 35v)

notice the equaliizer amp uses a 50v cap, while the control amp uses a 35v cap.

my first check would be that 35v cap, and put in a 50, and reconnect using a current meter on both pins.
that will be the quickest way to point tot he problem area.

btw the +32v regulator depends upon the +52v regulator's reference voltage to operate, and the -32v regulator tries to mirror the +32v regulator, until it is strangled by too much of a load, while it is only -12v, the regulator is turned on FULL...
 
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It's pin 10 that causes the drop (equalizer board). The control amp seems work since that doesn't affect the voltages.

5V across R1 with the eq connected. 2.8V without.

EQ draws between 60 and 110 mA (doesn't seem to be stable). Control draws somewhere between 16 and 24mA.
 
This is driving me crazy. I can't figure out what's broken in the equalizer.

I can disconnect certain resistors and transistors in the -32v region but no matter what i take away the voltage is still too low. It does however seem that everything that is connected to the -32 i somehow drawing to much current.

All of the transistors are okay. I've measured a large amount of points and crosschecked with my working 9800 but everything seems to be okay. I can't for my life figure out what's broken.
 
This is driving me crazy. I can't figure out what's broken in the equalizer.

I can disconnect certain resistors and transistors in the -32v region but no matter what i take away the voltage is still too low. It does however seem that everything that is connected to the -32 i somehow drawing to much current.

All of the transistors are okay. I've measured a large amount of points and crosschecked with my working 9800 but everything seems to be okay. I can't for my life figure out what's broken.

At this point it wouldn't be a bad idea to go back to the source itself, the power supply. You say the -32 volt line is low, but what about the others?
Attached is the power supply schematic. Are there any others voltages that test low? They are all circled.
 

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Rest of the voltages are okay apart from pin 9. It's 68v so the resistor isn't doing anything. That means the current draw is to little but even with the EQ it won't go down to -48v.

Without the -32 connected to the equalizer the voltage is -32v. When i connect the EQ there's a small flash and the voltage is dropped to -13v.
 
Rest of the voltages are okay apart from pin 9. It's 68v so the resistor isn't doing anything. That means the current draw is to little but even with the EQ it won't go down to -48v.

If you have the -48V which should be at pin 9 and the collectors of Q12 + 14,
then the resistor is obviously doing something. But make sure the resistor value checks ok at 220 ohms.

Without the -32 connected to the equalizer the voltage is -32v. When i connect the EQ there's a small flash and the voltage is dropped to -13v.

I'm still not entirely convinced there isn't a supply issue. You may be getting the right voltage with no load, but if there is an issue with the supply being able to provide enough current, the voltage will drop even if the load is working correctly. If you have some components at your disposal, you could rig up some sort of low current load using miniature indicator bulbs or leds, and load the circuit externally. If the voltage still drops, the issue is likely all in the supply and not the eq board.
 
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