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Pioneer SX-1250

xXColdShotXx said:
do you want me to post a pic that way you can see if the unmounted transistors are put in right?

here's a pic of it after i got done.


View attachment 240002

the soldering looks like crap because of my cheapo advance auto soldering iron i got for $5 few years ago, got a lil better 1 on the way.
View attachment 240003
Click to expand...
You're not really going to put that back into the receiver, are you??? My intention is not to belittle you, but you have to know yourself that that is unacceptable.
 
do the transistors look like they're positioned right? i know the soldering looks bad, but can't afford temp. controlled soldering equipment atm. i plan on re-doing it better when my cheap 25w 750 degree weller iron gets here.
 
i cleaned up the solder a lot, best i could with this soldering iron, put the board in and done the dbt test, bright at first then went real dim (using a 75w bulb) and i checked the dc-offset from speaker terminals on aux and A speaker selection and both sides are on 0v (200mv setting) still gotta do another awr-106 test to see if my numbers are right. i noticed my relay is clicking in a lot louder and not as fast as before.


AWR-106(stabilizer board) test red lead to pins, black lead connected to chassis. still hooked to the dbt while i tested it

pin 1 - -48.9v
pin 2 - 48.4v
pin 3 - 0v
pin 6 - 59.2v
pin 7 - 16v
pin 8 - 5.3v
pin 9 - 13.5v
pin 10 - 24.3v
pin 11 - 57.3v
pin 12 - 0v
pin 13 - -59v
pin 14 - -24.1v
pin 15 - 60.3v
pin 16 - -60.1v
pin 17 - 58v
 
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AWH-048(power amplifier board right side)

pin 1 - 14.1v
pin 2 - -60v
pin 3 - 58v
pin 7 - -1.6mv
pin 8 - -1.4mv
pin 9 - -1.8mv
pin 11 - .3v
pin 12 - 47.9v
pin 13 - -1.5mv
pin 15 - -47.8v
pin 16 - -.3v
pin 17 - -1.9mv
pin 18 - -2mv
pin 19 - -1.9mv

AWH-048(power amplifier board left side)

pin 1 - 14v
pin 2 - 59.4v
pin 3 - 57.3v
pin 7 - 4.7mv
pin 8 - 5.5mv
pin 9 - -1.7mv
pin 10 - 5mv
pin 11 - .4v
pin 12 - 47.9v
pin 13 - -1.5mv
pin 15 - 47.8v
pin 16 - -.4v
pin 17 - -7.8mv
pin 18 - -8.2mv
pin 19 - -8.1mv
 
most of what I see can be attributed to the DBT. a lot of the time the dbt prevents the protection relay from engaging because the power line voltage at the plug is too low.

plug the unit straight into the line and retake all the readings, - in some cases you skipped pins, just read them all and please be very careful to record the polarity correctly, and can you PLEASE stop using the - (minus or dash) as a spacer. It's giving me mental whiplash!!

follow the adjustment procedures (offset voltage, idle current) to get the appropriate readings BUT DO NOT CHANGE THE POT SETTINGS, NO ADJUSTMENTS YET, JUST READINGS!!!

things are looking good (except the solder joints in the pictures, but the revised joints appear to be working)

I couldn't tell from the pictures whether the transistors were in right, but the voltage readings so far seem to indicate they are correct.


we may end up doing a few parts on the protection board (6 caps and 3 transistors) but it too may be voltage starved by the dbt.
 
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here's another try like you said to do it, plugged straight into the wall

AWR-106(stabilizer board)

pin 1 -75v
pin 2 +75.6v
pin 3 0v
pin 4 0v (read anyway)
pin 5 0v (read anyway)
pin 6 +90.6v
pin 7 +24.5v
pin 8 +5.4v
pin 9 +13.5v
pin 10 +25.3v
pin 11 +71.4v
pin 12 0v
pin 13 -71.4v
pin 14 -25.3v
pin 15 -94.2v
pin 16 -71.6v
pin 17 +71.9v

i tested the mv's of the pins +7 and -19 on AWH-048 boards and got 0.4mv on both boards.
 
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Radio Shack sells solder flux. Go buy some. Take a small jewelers screwdriver and smear a very small dab on the bad-looking solder connections, then hit it with the solder iron and a bit of solder once more. If that does not improve the situation, you're hopelessly solder-challenged. (It's also possible that your solder tip is not clean...if wiping on a moist sponge isn't getting it cleaned up, go find a brass brush and with the iron heated up, scrub the tip good with it.)

Make sure to put the lid back on the flux when done, and store it in the fridge.
 
The BIG question, did the protection relay click in and stay in? So far the readings say it should.

The voltages on the power supply board are good now. We of course have to square away the solder joints for longevity, and polish the pins for reliable connections. This is important, as you can gather because everybody is harping on it... (also after disconnecting internal connections for anything, power up with the dbt connected first for a quick check that the bulb still dims, then take the dbt off and power up straight from the wall.)

I had expected you to repeat doing the voltage measurements ALL the boards you did the first time, both awh-048 boards as well.

then while reading the awh-048 boards,

edit - AH HAH, I see you did 7 & 19 to ground, this is a special case of reading voltage:

there will also be a voltage reading with the red probe on pin 7 and black probe on pin 19. That's idle current, computed using ohms law because we are measuring a voltage across a known resistance.

it will tell a LOT about the health of the receiver.

While you have the unit powered up, you can adjust the 106 card for +65 and -65v as per the instructions.
 
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yes the protection relay started working after i plugged it into the wall.
got more readings from AWH-048 and AWM-091.

AWM-091 board

pin 1 +70v
pin 2 0v
pin 3 -24.9v
pin 4 0v
pin 5 +19.9v
pin 6 +1.6mv
pin 7 +1.7mv
pin 8 +3mv
pin 9 +3mv
pin 10 0v
pin 11 0v
pin 12 75.3v
pin 13 -74.4v
pin 14 0v

AWH-048 board left side
pin 1 +16.4v
pin 2 -71.5v
pin 3 +71.5v
pin 4 0v
pin 5 0v
pin 6 0v
pin 7 +3.1mv
pin 8 +3.3mv
pin 9 +1.8mv
pin 10 +3.2mv
pin 11 +.4v
pin 12 +75.4v
pin 13 +2.5mv
pin 14 0v
pin 15 -75.1v
pin 16 -.4v
pin 17 +1.7mv
pin 18 +1.7mv
pin 19 +1.9mv

AWH-048 board right side

pin 1 +20.3v
pin 2 -71.6v
pin 3 +71.8v
pin 4 0v
pin 5 0v
pin 6 0v
pin 7 -.5mv
pin 8 -1mv
pin 9 -1.1mv
pin 10 -.4mv
pin 11 +.4v
pin 12 +75.4v
pin 13 -1.5mv
pin 14 0v
pin 15 -74.8v
pin 16 -.4v
pin 17 +1.5mv
pin 18 +1.5mv
pin 19 +1.7mv

let me know what else to do. thanks for the help, mark and echo. i clean the tip with a small brass brush every few solderings. it's just a piece of crap soldering iron as you can see from the welds in that pic. i did clean up the welds some, but didn't take a pic before i put the board back in. next time i take it out i should have a different soldering iron to re-do it.
 
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i set the awr-106 vr1 and vr2 to +65v and -65v and tested awh-048 pins 7 (+) and 19 (-) on the 200 ohm setting and got 23.1. i hooked it back up through dbt and it still dims good, but protection relay will not work that way, hooked into wall and protection relay is working. is it the bulb wattage causing the relay not to work?

the left side heatsink is not getting hot anymore, both are staying cool now.
 
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on the amp boards, you need to measure millivolts between pins 7 and 19.

please also measure VOLTS between pins 11 (red) and 16 (black) as well on the amp boards.

and the dbt should be removed, and the unit plugged directly into the power line before doing any settings.

Yes, the bulb makes the unit think there is a brownout, and the 120v power the unit expect from the wall is much less, not enough voltage for the protection circuit to think the power has been turned on.

you need to do the idle current setting - "9.3 power amplifier" procedure.

then the heat sinks should warm up a bit, equally. as they should.
 
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awh-048 pins 11(+) and 16(-) .8v both sides, pins 7(+) and 19(-) on right side i got .1mv and 1.0mv on left side. the dbt was unhooked when i done the last readings on those other boards and when i adjusted the awr-106 16 and 17 voltage settings. i beleive the pots on top of awh-048's are both turned all the way down (ccw).
 
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what kind of solder do you, mark and echo use, roll of solder or solder paste? i was thinking about getting some solder paste, but not sure how good it would work with a soldering iron.
 
i beleive the pots on top of awh-048's are both turned all the way down (ccw).
Click to expand...

They are to be turned up in the 9.3 procedure. Otherwise the sound is very distorted.
 
i don't have any 5.1k ohm resistors. can i still do it without them? i hope this fixed both channels. i am still planning to rebuild more boards in a few months though.
 
i adjusted them to about 99.7mv on right side and 99.8mv on left side and it's been on for over 20 minutes. the old vr1 and vr2 pots on the awh-048 boards are junk, hard to adjust. i am gonna get more next time i order parts for it.

both heatsink's get warm now, not too hot.
 
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