Pioneer SX-1010

Thanks Loweran. It has been a great challenge and I have learned a lot from you guys so far, especially you and Zebulon1. Great forum.
As for what's next, I have to locate a chip and I will probably turn to Zeb's EBAY connection there for that.
I am hoping it does not have to be aligned and I would think it shouldn't because I am not really moving anything in terms of current, just swapping out parts. I hope someone here will chime in and let me know because if that is the case, I am dead in the water.
Going shopping now! Anyone know of any other sources for these chips?
 
If the alignment was good before the chip replacement then it should be good to go with the new IC installed.
It seems the chip and the high voltages confirm it.
The chip is cheap so your not out to much in the repair.
 
Thanks Zebulon. I will try to track one down locally and if not, head to EBAY to buy. I should know tomorrow which way I am going.
 
Well, great news here. I found a HA-1137 chip and socket on EBAY, installed it and now have a fully functional SX-1010 thanks to you guys here on the forum. In particular, I have to take my hat off to Zebulon who has been here the whole way through and saw this one to the end. I had to talk you in to jumping on board but once there, you stayed with me and helped out a ton. Thank you.
Loweran, thank you for your input and your insight on tickling the dragon. he's still laughing.
This is a great forum and I like the fact that you guys don't run people into the ground, even when they ask the simplest of questions.
Cheers boys, you are #1 in my books

Bill

I see there is another SX-1010 in need of some guidance. Maybe I will jump in and offer my two cents worth :)
 
Unh unh - several circuit positions in the past come to mind where the resistor reading was spot on IN-CIRCUIT, and out of circuit it was open circuit.
The FIRST time that had me going round and round (long ago...) and the circuit was driving me nuts. Then when I figured it out... jawdrop city....

Now normally I don't reveal; or advocate my procedures, because I preach "one component at a time" (and they are contrary to that message, which is best for all but those capable of writing their OWN rules), but I just go through the back of a board with my desoldering gun and open up all the resistors. Then test read them from the front side. Before e-caps. Before transistors OR anything else. THEN I test (out of circuit) transistors, and look at the original e-caps.

Remember - I do my homework for each board FIRST, gathering all components, arranging them on a holder (antistatic) with a 1:1 correspondence to the board being worked on. And then I swap old for new in BOTH - thus when I am done I have all the NEW components in the board and all the OLD components in the holder - indexed for reference and referral. And I KNOW which of the old components were deficient. I don't HAVE to remember, the bench TELLS me.

First I'd like to congratulate Bill on a job well done.

Mark, would you mind posting a picture of your antistatic holder that you use to swap out your components. I'll be working a receiver in the near future and that sounds like something that would be very useful.
 
Well, as Jack Nicholson said in "The Shining".......I'm back :(
So this unit has been out for a while working okay. I got it back with the main fuse melted. Kind of odd way to blow but it did blow. So I put the DBT on it and sure enough, nice and bright. I checked the 0.01 cap on the input side and no problems there. I checked the voltages on the main caps and found 1 - DC = 3.095 and Ac = 3.139 2 - DC = 3.139 and AC = 0.057
So I suspect the problem may lie in the rectifier? Do I need to disconnect from the circuit to test it and are we talking about the one on AWR-063 and not AWR-064?
Also, should I be checking outputs and if so, which transistors in particular?
Lastly, if it is on the secondary side, why does the main fuse blow when it is on the primary side of the transformer? Thank in advance for any help. You guys got me through it once before and I am sure you will do it again. Cheers
 
Lastly, if it is on the secondary side, why does the main fuse blow when it is on the primary side of the transformer? Thank in advance for any help. You guys got me through it once before and I am sure you will do it again. Cheers
It just does. :dunno:


Checking for volts with the DBT will be inaccurate.
Remove fuses 5 and 6 that supply the rectifier on the PS board for the regulated. DBT it. If bright:
Then:
I think I would look at the outputs.
If you changed the large filters with screw type terminals, remove the leads to isolate the rails to the outputs and see if the DBT remains bright. If it dims one or more outputs are toast.
If bright, the big unregulated rectifier on the fuse board or the transformer might be the culprit.
 
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Okay so I did some digging around and here is what came of it. I removed the three red wires on the lower cap and the short went away. The one that took it out was the one going to pin 16 of the Power Supply board. I took the board off, checked it over, soldered up some bad joints and reinstalled. Light went bright for a minute and then dimmed down. Now I am reading 42 volts on both caps and they discharge very slowly when turned off, the top one taking longer than the inside one. So I checked the 3.3K ohm resistors and they were both okay( 1 leg lifted). Then I checked the power caps and here is where I think I have a problem. My meter is reading 16,220 uF on the inside one and 13,337 uF on the outer one. So I am thinking I have bad caps. If anyone can confirm, any sources of these anywhere that is known to exist?
I am hoping Digikey has something as I have an order going in shortly.
 
The two power caps are replaced and onwards we go. DBT stays bright when turned on so I isolated the power amps from each other. When I disconnect one, the DBT dims down so I suspected a problem on that board. Removed it and tested everything on it and found nothing. Now I am suspecting output transistors. What is the best method you guys have found for testing these? I have tried a couple of methods and found differing results but I think there are a couple of bad ones here. Just want to confirm my suspicions. Can these cause my problem and not hurt the amplifiers?
 
When working on the power amps, you DID turn the idle current adjustment back to minimum before powering it up?

Because the power amps (usually any model generally) can be dialed to a point of extremely large currents.

That's what your symptoms remind me of.

and for danrclem:
my "antistatic" holder is a large piece of 1/4" thick conductive (crumbly) foam sheet that Integrated Circuits with pins are stuck into and shipped on.
https://www.amazon.com/FOAM-CONDUCTIVE-ANTI-STATIC-INCH-x12/dp/B00B88717I
underneath is a styrofoam sheet for mechanical support.

And someday I'll come across a black antistatic polyethylene foam block and then use it.
 
I have not powered it up since I removed the power amp board. I was just going to connect the power amp back up when I decided I should test all the output transistors while I was there. I have tested them and Q1 and Q2 are shorted. Now I must go on the hunt for some transistors to repair. Any recommendations on substitutes?
 
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MJ21193G and MJ21194G are the commonly used replacements. I'd replace all of them.
 
Good Morning. I am back at this unit again. Had a blown output transistor on the power amp and I replaced all of them to be on the safe side. Not sure what caused it but it has been running good. I am checking all my voltages before tickling the dragon again and on my power amp I have 43.7VDC on pin 8, both boards and -43.7VDC on pin 11, both boards. I am running with DBT.
I checked my AC voltage on pin 1 and 2 of my power supply assembly and found 72.4 VAC which I think is a little low due to DBT. I disconnected pin 8 on both boards and they came up a little to 46.6 VDC but still nowhere near 54VDC which it should be. I had installed new power caps C9 and C10 on the power supply but I wouldn't think that is the problem ? Any ideas or is this normal? Thank you in advance.
 
Your fine.
If the DBT is dim and the voltages are equal, it should be running well on full power.
Go for it.
Remember to dial back the Idle trimmers before going on full power and rechecking the amps.
 
Dialed them back already. The DC Neutrals seem to be all over the place. Any reason for this? I think I had this the last time I went through this process and everything seemed to work out. Any thoughts?

Okay the unit is now working. Missing left side outputs? The speaker is very weak and distorted when balancing to left side. Going to take some measurements and see what is going on here. Other side sounds good.

Found that if I powered the unit off and then on again, left side would come in and work normal for about 15 seconds and then fade to a crackling audible signal. Repeat On-Off, same thing each time. Solder joints? Where to start?
 
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Cant remember and too lazy to read back. Did you clean up all the controls? Could be a volume or balance knob needs to be cleaned.
 
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