Wanted to reach out to ask if anyone has worked on one of the infamous Pioneer flagship SC-09TX Receiver. I have one here that's getting the dreaded Phase Control Light error. The receiver turns on and shuts right back down within 2 seconds. There is no obvious signs of bad caps and the transistors on the power amp seem to check out. (No shorts or open circuits). I've seen a few of these receivers and they all seem to have the same issue. A web search does not show any repair help on this receiver. Any help would be appreciated. I have minimal test equipment but have some electronics skills. I have both the service manuals on hand.
Schematic::
https://elektrotanya.com/pioneer_sc-09tx_sm_1.pdf/download.html
Service Manual:
https://elektrotanya.com/pioneer_sc-09tx_sm_2.pdf/download.html

 

I have one here that's getting the dreaded Phase Control Light error. The receiver turns on and shuts right back down within 2 seconds.

The only mention of "Phase Control" in those documents is due to overcurrent or DC in the output amplifiers. Do you have anything hooked up to the speaker outputs? Maybe look for short circuits at any of those outputs. I'm not sure how they're measuring the current, but that could also be the source of the problem.

 

There is nothing connected to the speaker terminals but I have read a speaker short will cause this error also, but temporarily. Mine won't reset at all. I've tried manually resetting but it goes right back in protection. I do think the problem is in the power amp section but for some reason there isn't much info in the service manual about the ICEPOWER Amp. Not even the Schematic.

 

here's your problem it's the Pioneer’s MCACC (Multi-Channel Acoustic Calibration) it compensates the
equalization on each channel and can include your room’s reverberation in its calculations. It compensates for standing waves, tweaks phase, and can save up to six setups (at different listening positions, for example). You can even link a PC to the receiver to help with the setup (using a special downloadable program from Pioneer. Good luck to you.

 

Has anyone worked on of these beasts?

 

here's your problem it's the Pioneer’s MCACC (Multi-Channel Acoustic Calibration) it compensates the
equalization on each channel and can include your room’s reverberation in its calculations. It compensates for standing waves, tweaks phase, and can save up to six setups (at different listening positions, for example). You can even link a PC to the receiver to help with the setup (using a special downloadable program from Pioneer. Good luck to you.

DELTA PRIME - Can you be more specific? Why would the MCACC cause the Receiver to shut down in Over-current? Is this a firmware issue?

 

here's your problem it's the Pioneer’s MCACC (Multi-Channel Acoustic Calibration) it compensates the
equalization on each channel and can include your room’s reverberation in its calculations.

I wonder if it requires the speakers to be connected, in order to power up?

 

I wonder if it requires the speakers to be connected, in order to power up?

I do not think this needs speakers connected for the amp to at least power on. Pin 21 of the SYSTEM u-COM is labeled as AMP OL DET (Amp Overload Detect) and could be the trigger input (or not). It I just have no clue what voltage or signal because there is no Schematic for the Amp. If someone can help me get this operational, I'll pay them.
BTW I am not a repair shop, I am an end user repairing this for my personal use.

 

BTW I am not a repair shop

Me neither! I am just a hobbyist, not an expert. I see on page 101 of the schematic, the "AMP OL DET" signal comes in from the right at 24 pin connector CN8301. It goes off the left side to page 100 where it connects to the input of an opamp of some kind. The output of that opamp goes out the left side of page 100 at the 19 pin connector CN8304. Maybe you could start by unplugging and re-plugging these cables? Page 68 of the service manual shows the 24 pin cable as "E". I can't find the 19 pin one anywhere, but at least this is a place to start. That amp is a monster!

 

Me neither! I am just a hobbyist, not an expert. I see on page 101 of the schematic, the "AMP OL DET" signal comes in from the right at 24 pin connector CN8301. It goes off the left side to page 100 where it connects to the input of an opamp of some kind. The output of that opamp goes out the left side of page 100 at the 19 pin connector CN8304. Maybe you could start by unplugging and re-plugging these cables? Page 68 of the service manual shows the 24 pin cable as "E". I can't find the 19 pin one anywhere, but at least this is a place to start. That amp is a monster!

Yeah thanks Chris. This amp has so many connectors it wouldn't surprise me if one was loose. I'll definitely try this and check for open contacts on those connectors.

 

I do think the problem is in the power amp section but for some reason there isn't much info in the service manual about the ICEPOWER Amp

Page 46 flowchart ice power amp follow .report back

 

Page 46 flowchart ice power amp follow .report back

So I put the amp back together and realized that it would be very hard to test for voltage per flowchart because the unit stays on for only 2 seconds. I was able to determine that there was no voltage on the 12v and 5v regulators. However, I disconnected the HDMI board and the power stays on with a continuous blue light on the power button. The front display assembly does not work with this board removed. There is a possibility that something on the HDMI board (AE) is causing the over current protection.

 

Let us both reference the
10. SCHEMATIC DIAGRAM
10.1 OVERALL WIRING DIAGRAM
Now describe to me where the 12 volt and 5 volt regulators are with respect to the wiring diagram also there is a reference marker list we can also use and everything is categorize by assemblies so did you disconnect AX, DD HDMI Assy. Along with AY, HDMI diode Assy.? By the way this is pretty ambitious for an end-user I like your style.

 

Let us both reference the
10. SCHEMATIC DIAGRAM
10.1 OVERALL WIRING DIAGRAM
Now describe to me where the 12 volt and 5 volt regulators are with respect to the wiring diagram also there is a reference marker list we can also use and everything is categorize by assemblies so did you disconnect AX, DD HDMI Assy. Along with AY, HDMI diode Assy.? By the way this is pretty ambitious for an end-user I like your style.

The HDMI assembly I disconnected was AE, not AX (DD HDMI Assy). Board AQ is the 5v regulator and board AR is the 12v regulator. These regulators power the ICE AMP. I didn't mention that while the HDMI board (AE) was removed, there WAS power output from these regulators and I actually heard the main relay click on!. I had the +5v, -5v, +12v, and -12v but only with the HDMI board (AE) removed. It seems like it is not going into over current with AE removed. So that narrows things down a bit. Debating whether I should try to replace the entire HDMI board. You would have to be an engineer to troubleshoot this board. My concern is that it may be something in the display or something else. I even narrowed it down to a single connector on the HDMI board. Connector CN804, which goes to the mother 1 Assy (V), is what's causing the overload.

 

I even narrowed it down to a single connector on the HDMI board. Connector CN804, which goes to the mother 1 Assy (V), is what's causing the overload.

This is some good progress! That connector has +12v and Ground and a bunch of interface signals. I'd check for a short circuit on CN804 pins 17 and 18. Maybe there's a fried capacitor somewhere? Or chip transistor Q803 shown on page 140 could be burned too. I've never tried to repair SMDs, so I can't help much there. Does the HDMI fan run, when only CN804 is disconnected?

 

Referencing the service manual
Have you tried to put your unit in service mode that process can verify your observations.

 

Referencing the service manual
Have you tried to put your unit in service mode that process can verify your observations.

Unit will not stay powered on long enough to put into service mode

 

All right I think we should take a deep breath. Now given the information that you have provided and what you have already started. And I'm not trying to beat you up but safety is Paramount you are aware of the hazards deadly hazards of your unit correct? If so for kicks and giggles point out what you would think are lethal voltage's on your unit . Because you will probably proceed with or without assistance. And I would be negligent not to ask these questions for your safety.

 

You're right about safety. Everything in this unit is potentially lethal. I am a journeyman electrician so I've been hit with some very high voltage a few times. Nothing like getting hit by some 277 at 6:00 am lol. Believe me that's worse than a flyback transformer. But other than live testing I always power the unit off and give time for caps to drain off. Thanks for pointing that out.

 

You're right about safety. Everything in this unit is potentially lethal. I am a journeyman electrician so I've been hit with some very high voltage a few times. Nothing like getting hit by some 277 at 6:00 am lol. Believe me that's worse than a flyback transformer. But other than live testing I always power the unit off and give time for caps to drain off. Thanks for pointing that out.

BUMP...

So I just bought a SC-09 and it might actually be this exact receiver, or it might be that mine simply has the exact same problem.

But I wanted to check and see if you guys ever worked out a solution to this problem, or a work-around, or if anyone figured out what the cause was? I'm more than ready to replace some SMD's or unplug a connector if anyone can advise what to look into.

Additionally, has anyone considered reflowing the HDMI board? Seems like 50% of Onkyo HDMI boards needed to be be reflowed eventually and it usually fixed whatever problem they were having. I wonder if doing the same would help here for the SC-09?

Any help or updates would be greatly appreciated!

Thank you guys!

EZ