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Pioneer SX-5590 Relay & Lamp Blinking Issues

basicblues

basicblues

Well-Known Member
I aquired a Pioneer SX-5590 (SX-1250) a couple of years ago. I had so many projects at the time I decided to set it aside until I could devote the necessary time to restore and repair. So in the meantime I rounded up a switch I needed (thanks Echowars) and a couple of missing knobs.

This one is a beautiful clean unit that I hope will have a place of prominence among my other monsters. Over the last couple of weeks, I've mainly just been detailing the unit and refinishing the wood & metal parts (no not the faceplate too).

Close inspection reveals the unit is likely to be all original inside. I knew when I got the unit that it might have a few (hopefully) minor issues. When the unit was intially powered on, the relay clicked and produced sound on both channels. Then the sound disappeared, then right back on again a few seconds later. The unit was disassemabled as necessary to allow full access and proper cleaning of the controls & switches which is just about an all day deal. Finally, and slowly the unit was back together enough to start testing. The second power up: still have sound in both channels, still intermittent with popping in the right channel. Inbetween relay clicks, I saw a good "flash" inside the relay. The unit still works but now the relay takes longer to engage and I have popping along with sound in both channels.

Since I haven't been able to stablize the unit enough to test and before taking the next step to clean and burnish the relay. Is there anything else I might need to check first?

On the indicator lamps: The A/B/C speaker indicators & the function indicators (AM/FM/etc) blink on and off. When the unit is first powered on, the selected indicator lamps work as they should, then blink off for several seconds, then back on again, then repeats with time on/off varying. All of these lamps as well as the panel lamps work and doesn't seem to have any connection to other issue as described above.
 
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Never been inside a SX-5590 or 1250 , But have you looked the fuses over for a bad connection / dirt ??. Tried tapping the relay ? Or for loose wire connections ?
Sorry can't think of anything else,
Barney
 
Check your power supply voltages and see if they toggle on and off in sync with the relay and lights.I'm think'n power supply issue...:D
I saw a good "flash" inside the relay.
Click to expand...
Thats called arc flash that means the relay contacts have established current flowing through them. Not really a good thing especially if the relay keeps cycling -carbons up and pits/burns up the contacts.:scratch2:
Another thought,disconnect your speakers while your T-shooting your toggling issue .That way there will not be any current flow thru the relay contacts.Thus no arcing!
 
Polished up the relay contacts, the relay does work better but still has "arc flash" so I quickly turned the unit off. Now I'll be checking the power supply next...
 
It looks like you have a power supply issue with those blinking lamps.

The illumination lamps run DIRECTLY off the transformer, while the function lights and the speaker lights run off a regulated DC voltage (5.4v for longevity) from the power supply.

Please check all FIVE fuses VERY carefully, there could be some weird interactions as the orange and green secondaries are part of the SAME winding.

Then check the solder joints around Q12 and Q13. It is possible that C18 is very leaky or shorting out. To diagnose the lamps further would mean taking voltage readings and watching the readings while the lamps are blinking. Plus while it's hard to tell, are the lamps brightening and dimming, or abruptly turning on and off?

The "flash" you see, WHICH relay is it? The soft start or the protection relay?

Does it flash (if it's the protection relay) with NO speaker loads connected?

You might want to check the regulated power supply voltages (pin 1 is +65v, pin 3 is -25v) to see if they are stable. It may be the amp rather than the protection circuit, so reading the amp output voltages at pins 6 & 9 on the protection board would be a good idea.

edit: the protection circuit has it's own +35v voltage regulator!! Check C5's positive terminal for a stable 35v...
 
Damn...I miss too much when I scan these posts. Didn't see the blinkin' lamp deal.:scratch2:
 
EchoWars said:
Damn...I miss too much when I scan these posts. Didn't see the blinkin' lamp deal.:scratch2:
Click to expand...

I almost missed it too, but then I caught the part about the protection and lamp cycling didn't seem to have a connection I was really curious.
 
markthefixer said:
Please check all FIVE fuses VERY carefully, there could be some weird interactions as the orange and green secondaries are part of the SAME winding.
Click to expand...

I took each fuse out and tested them individually, all tested good.

markthefixer said:
Then check the solder joints around Q12 and Q13. It is possible that C18 is very leaky or shorting out. To diagnose the lamps further would mean taking voltage readings and watching the readings while the lamps are blinking. Plus while it's hard to tell, are the lamps brightening and dimming, or abruptly turning on and off?
Click to expand...

With the AWR-106A board removed, I resoldered points Q12 & Q13 and both points of C18. I turned off the lights in my shop and powered on the unit to see if I could distinguish any indicator lamps dimming before shutting off. Yes, the indicator lamps very slowly dim to the point where they are completely off. Oddly, I may have done something that has stopped them from bouncing on/off but I would have to watch it a little closer to confirm. The lamps power on fine at the initial power on but within a minute they fade out. If I cycle the power off and wait a minutes the lamps still will not power on, after it seemly cools down the lamps will act as before at initial power on.

markthefixer said:
The "flash" you see, WHICH relay is it? The soft start or the protection relay?
Click to expand...

The flash I was seeing was in the protection relay.

markthefixer said:
Does it flash (if it's the protection relay) with NO speaker loads connected?
Click to expand...

I disconnected the speakers and I could NOT see any internal flashing of the relay.

markthefixer said:
You might want to check the regulated power supply voltages (pin 1 is +65v, pin 3 is -25v) to see if they are stable. It may be the amp rather than the protection circuit, so reading the amp output voltages at pins 6 & 9 on the protection board would be a good idea.

edit: the protection circuit has it's own +35v voltage regulator!! Check C5's positive terminal for a stable 35v...
Click to expand...

Man here's were some troubles show up. Here's the DC voltages I got from the points you suggested.

C5= 24v
Pin 1 = -71v
Pin 3 = 0.2mv
Pin 6 = -44v
Pin 9 = 1.998v
 
That FLASH is BAD, it is DC current going through your speakers!! Until this is fixed, if you value your speakers, you will NOT hook them up!!!!!!

With the lamps fading, there is probably a problem with one of the two capacitors (C18 & C19 47uF 10v) in the circuit, either one is shorted out and the transistor is cooking itself driving the shorted cap, or the other one connected to the base of Q13 is very leaky and shorting out slowly as the temperature rises, at least in this second scenario the transistors are not getting fried, just turned off slowly.

Either way, you will fix it as part of fixing the BIGGER fish you have to fry...

The 0.2mV on pin 3 of the protection board OFFICIALLY makes this a power supply (stabilizer assembly awr-106) problem. The fact that the voltages on pins 6 & 9 (the amplifier outputs) are at -44 and +2 volts is immaterial until we get the -24 supply on pin 3.

The presence of -71v on pin 1 indicates even bigger problems on the awr-106 board. Even if it were +71, it is supposed to be +65v.

So, on the power supply for the sx-1250, take all of these measurements:

stabilizer assembly
awr-106

pin 1 input -62v raw dc on the big caps
pin 2 input +62v raw dc on the big caps
pin 3 ground
pin 4 ac red transformer leads
pin 5 ac red transformer leads
pin 6 +85v input
pin 7 +23v input
pin 8 +5.4v OUTPUT
pin 9 +13.5v OUTPUT
pin 10 +25v OUTPUT
pin 11 +65v OUTPUT
pin 12 ground
pin 13 -65v OUTPUT
pin 14 -25v OUTPUT
pin 15 -87v input

You will have several transistors to replace, and I recommend a re-cap of the board with 105 degree c nichicon PW (upw)or HE(uhe) caps (mouser) or Panasonic FC or FM caps (digikey). Plus a few on the other awr-107 board (two 470uF 100v axial and 470uF 25v radial).
 
Thanks again for your help. I pretty much knew the score when I saw the negative voltage as I had a similar issue with a Sansui receiver.

I am confused about the all measurements you wanted me to take on the power supply. Are you referring to board the stabilizer assembly
awr-106 board? and are the voltages you listed what I should be getting with a working board? (I haven't looked in the service manual yet).
 
basicblues said:
Thanks again for your help. I pretty much knew the score when I saw the negative voltage as I had a similar issue with a Sansui receiver.

I am confused about the all measurements you wanted me to take on the power supply. Are you referring to board the stabilizer assembly
awr-106 board? and are the voltages you listed what I should be getting with a working board? (I haven't looked in the service manual yet).
Click to expand...

Yes, those are the correct voltages for the awr-106 board. With all of them taken it will be easier to sort it all out, just copy the list and add your readings. Skip the ac voltage readings if the 13.5v is present.

We will primarily be concerned with the output voltages, but we need to be sure the inputs are there to generate an output.
 
pin 1 input -62v raw dc on the big caps -72.8v
pin 2 input +62v raw dc on the big caps 72.5v
pin 3 ground -00.2mv
pin 4 ac red transformer leads -46.6mv and -.444v
pin 5 ac red transformer leads -44.4mv and -.443v
pin 6 +85v input 90.8v
pin 7 +23v input 24.83v
pin 8 +5.4v OUTPUT 2.040v and 1.203v
pin 9 +13.5v OUTPUT 13.13v
pin 10 +25v OUTPUT 24.31v
pin 11 +65v OUTPUT 65v
pin 12 ground 00.3mv
pin 13 -65v OUTPUT -65.8v
pin 14 -25v OUTPUT -25.16v
pin 15 -87v input -93.4v


Really weird business going on with pins 4 & 5, I could get a millivolt reading a couple of times then back to a volt reading mostly. I checked all 15 pins about 4 times for consistency and these results were typical.
 
First, when measuring pins 4 & 5 did you switch over to AC volts, otherwise you CAN get strange readings.

BUT, the rest of the voltages are quite acceptable. That looks like a working power supply regulator.

The protection board pins:
Pin 1 = -71v should be +65 v dc
Pin 3 = 0.2mv should be -25 v dc
Pin 6 = -44v should be in the millivolt region
Pin 9 = 1.998v should be in the millivolt region

What are the readings on the protection board now?

IF the protect circuit hasn't tripped, then the fault hasn't occured, and everything will be ok until it goes wrong again, and you have to catch that.

Something DID go wrong to get the readings you did on the protection board. We just have to catch it in the act.

As for the lamp circuit, try removing C18, (it really would better to replace them if you can, 2 x 47uF 10v or better(v)) or swapping C18 and C19 and see what happens. It will either shut down completely, or the leaky cap will be in a position where it is more tolerated.

I suspect that when the power supply gets hot, it malfunctions. Check all the solder joints, and redo the ones on the power transistors just for grins, as sometimes the cracks are hard to spot without a really good magnifier. I use a sharp dental pick and see if i can coax movement, if I just don't clean the joint and redo it as a matter of course.
 
Yeah, I had the meter in the wrong mode with pins 4 & 5. After I switched to AC I got these readings.

Pin 4 = 53.6v
Pin 5 = 53.8v

I think I initially measured pins on the AWR-106 board instead of the AWM-091 protection board. Probably lack of sleep but here's the results.

The protection board pins:
Pin 1 = -71v should be +65 v dc 63.7v
Pin 3 = 0.2mv should be -25 v dc -24.51v
Pin 6 = -44v should be in the millivolt region 01.8 to 06.1mv
Pin 9 = 1.998v should be in the millivolt region -13.5mv

I did the flip-flop with C18 & C19 and the indicator lamps powered on as before and after a few seconds flickered twice and went off.

I checked and touched up the solder on the AWR-106 transistors, are these the ones you were referring too?
 
Yes, they were.

Now we wait, for it to malfunction, and try to get those last 4 readings again when the protection relay trips (the speakers) off.

Remember, that POP from the speakers was real...
 
Got my test speakers hooked back up and the receiver is definitely working much better than before. Catching it in the "act" now is more difficult. It has been playing on my bench for the last couple of hours without many or any issues. There have been 2 incidences where I thought I heard a light pop in the right channel but not 100% positive. One of my $5 test speakers now has a small amount of distortion at low volume from the previous malfunction episodes. I switched everything around a few times to make sure it was the speaker instead of the receiver acting up. When more volume is added the bad speaker will sound more like it should. The confidence level is not yet to the point of using better speakers therefore I am hesitant to do so. The indicator lamps still do not work, all the other lamps still work fine.

The unit appears to be stable enough now to run further test. Before I go meter happy let me know what to check first before moving to the next step. I am still suspicious of a failing part in progress when the unit heats up.

EDIT: Well I posted too soon... I came inside to get something to drink, went back out and the receiver had stopped working. All the lights are off, no sound and will not power back on. I took each internal fuse out and tested, all are still good but as usual I forgot about the euro voltage selector 12a fuse on these SX-5590's which was blown.
 
Now checking and looking to see if I can find anything obvious. Checking the AWR-106 power supply board I can see a small amount of soot at the lower bottom on one of the 220uf80v capacitors. Other than that, some darker discoloration in that area from the excess heat.
 
There is a sixth fuse, a 12 amp fuse that is not on the circuit board with the other five fuses.

Or it could be a separate failure, in the soft start circuit.

There is a resistor (3.3 ohm 20 watt) and a thermal overload (microtemp 109c 15a) in series with the primary that the relay shorts out after the capacitors charge. Either could have opened up and caused what you see.
 
markthefixer said:
There is a sixth fuse, a 12 amp fuse that is not on the circuit board with the other five fuses.

Or it could be a separate failure, in the soft start circuit.

There is a resistor (3.3 ohm 20 watt) and a thermal overload (microtemp 109c 15a) in series with the primary that the relay shorts out after the capacitors charge. Either could have opened up and caused what you see.
Click to expand...


I must have been editing or adding to one of my last post when you submitted your post. Yes, the 12 amp fuse was blown...
 
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