Pioneer SX-1010

Adam60

Member
Hello, first post here. Hoping to find some answers. I am having an issue with an SX-1010 power supply and not sure where I am going wrong. Perhaps someone could help me. This unit had a fried resistor, I believe it was R12. The PCB was damaged so we built a new one and put the components back on. With the board disconnected except for pins 1-2-3-4 and 5, referencing pin 7 as ground, we get the following voltages:
Pin6 = 6.5 VDC
Pin7 - Ground
Pin8 = 2.2 VDC
Pin9 = -76 VDC (-9VDC)
Pin10 = -76 VDC (-56VDC)
Pin11 = -76VDC (-24VDC)
Pin12 = Ground
Pin13 = 2 VDC (35VDC)
Pin14 = 3 VDC (56VDC)
Pin15 = 3 VDC (24VDC)

http://www.kallhovde.com/pioneer/sx-1010sm.pdf


I have uploaded a link to a service manual here. I know there is a couple of gurus on here so I am hoping they can help me figure this out. Let me know what I need to do.
 
Built a new power supply? Can you show some pictures and the parts you used in the build.
 
I can but not right at this moment. I could use some help wading through this power supply though if someone has some experience tracing through it with voltages. Anybody?
 
Are you using a original SX-1010 PS board from a donor set?
You make it sound like you manufactured a replacement board.
 
Hi Zebulon, Happy to hear from you. I was just reading another thread with Pioneer fan. Yes I did build another PCB for the power supply and may be in trouble now. I have really funky voltages and I am not seeing what I need to see. I think the original problem could have been simple but turned into a mess. The owner decided to swap out a bunch of parts and the PCB traces were lifted off the board so I manufactured another board and installed all the parts on the new board. I measured all the components and checked and double-checked all traces and components. Now I am where I am. Hope you can help.
My problem is I don't have the unit in front of me so I could be a little time between answers. Where can I start?
 
Okay here are the voltages as referenced to pin 7 (chassis ground):
Pin 1 = 61VAC
Pin 2 = 61VAC
Pin 3 = 22VAC
Pin 4 = 22VAC
Pin 5 = 6VAC
Pin 6 = 6.5VAC
Pin 7 = Ground
Pin 8 = 2.2VDC
Pin 9 = -76VDC
Pin10 = -76VDC
Pin11 = -76VDC
Pin12 = Ground
Pin13 = 2VDC
Pin14 = 3VDC
Pin15 = 3VDC
 
I can't really help in this. A board you made, may work but what we would be doing is more R&D than repair.
Your drive to fix the set using parts other than OEM is admirable but finding a Pioneer PS board made for the set is a quicker way to a repair. And one we could help you with.
I looked and I don't have any PS boards in my box of 1010 parts. How bad was the original board? Post pictures of that when you can. You would be surprised how well repairs on seriously damaged and cracked boards turnout.
If your worried of the wrath you'll get when you post any images - and we see that you messed with the wire wraps; I promise "I" won't comment on it. :eek:
 
I'm not worried about anything that is damaged on the old board or whether or not the new board is correct. What I need to know is how close my voltages are and where they may be going sideways. I would like to think that you guys have a little more experience than I do and can perhaps point me in the right direction. These voltages are with the PS disconnected from everything and I hoped someone else had these voltages around. I am going to connect it back up to the power amp assembly which I believe caused the problem in the first place. Making a new board or buying a good used one should have no bearing. The diagnostics remain the same. I am to the understanding that some of you have extensive background on these units and I am hoping to tap into this and perhaps we can solve it together. This unit is 50 miles away from me and I am flying blind. I am telling the owner what to measure and then trying to figure out where he should go next. Right now, I am thinking my problem is in the upper half of the board. Any ideas would help. :)

I am wondering about my transistor pinning. Does anyone have a datasheet for the 2SA628A? I am wondering if this might be my problem. Also have to look at 2SC869. I think something is off about the diagram from Pioneer? Any thoughts?
 

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I'll take a shot at it!
The negative regulator with Q4, 5 and 6 seems to be working. Without any draws the voltage will be equal at the pins 9, 10 and 11 (But 76v DC seems high for 61v AC from the secondary?).
The function lighting circuit is supplied from pin 5, 6v AC through D7 and out as 6.5v DC seems good.
The positive regulator with Q1, 2, 3, and 8 is not working and seems to be missing voltage from the rectifier.
Without the positive regulator working, the 13.5 volts (Q7 and D10) for the tuner, at pin 8 is inop (missing the voltage).
So get the positive reg working and it all should fall into place.
What is the collector of Q1 reading? Is the 32v zener, D8 in backwards?

By the way the made board looks good. :D
And this whole arrangement by us helping you to tell the guy 50 miles away what to do is convoluted and will begin to haunt you. :rflmao:
 
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Hey Zebulon, I appreciate you taking the time to help me out. I had asked him to give me the whole unit so that I could work on it faster but he seems to want his hand involved and you are right, it will haunt me until it is done. Anyways, I will check into the things you mentioned and the only thing that is bothering me is the orientation of the transistors. He has NTE194's in place of the 2SC869'S. Also have pic of the old board and the 2SA628A's are facing a different direction than the way I have them. I have to make sense of that as well.
 
The 869's (Q2 and Q3) are not the same leg placements as the newer transistors. We use the Fairchild KSC2383's which are ECB (NTE's, eckee!). The center collector leg will be FWD instead of back on the board.

A list of equivalent, proven, Mouser (Fairchild) transistors that we use on the SX-1010 PS:
Q1: 2SD313: 863-MJE15032G
Q2: 2SC869: 512-KSC2383YBU
Q3: 2SC869: 512-KSC2383YBU
Q4: 2SB507: 863-MJE15033G
Q5: 2SA628A: 512-KSA1013YBU
Q6: 2SA628A: 512-KSA1013YBU
Q7: 2SD313: 863-MJE15032G
Q8: 2SC1384: 512-KSC2690AYS
 
Geez I could use two of those boards, I have two 1010's here with broken power supplies, so bad they cannot be fixed.
 
Hey guys, I'm back. Sorry I got cutoff by a power outage midway through my last post and surprised it posted anything. 18 hours without power, Grrr!
Anyways, Zebulon thank you for the equivalents for the transistors. I will file that away for later. I am still waiting for collector voltages to see where we are at. I will let you know.
TSD71, I took the PCB layout from the service manual and flipped it over to get the proper orientation (Paint) and then I put it into a word document and formatted the board size first. With the diagram in the background , I placed all the pads first and then connected them all using the "Insert" - Shapes - Scribble line. It worked really well once I caught onto it. The actual board took about 1.5 hours to develop. On Youtube, "MAKE" has a good tutorial on etching a PCB and although I hadn't done one since high school, it came right back to me once I started in on it. Very cool process. The board itself turned out really well, I drilled it and then checked all the traces (fixed a couple minor imperfections) and then checked and mounted all the components. If nothing else, it was a good project just for fun. Now I have to figure out where the problem is and that has me a little kerfuffled. We will get there.

I have attached a picture of the old board and you can see the orientation of all the transistors. I also have a picture that is labelled the way I see the layout diagram and to my knowledge, all transistors from left to right across the face are E-C-B or E-B-C and yet, they seem to be backwards? Maybe I am looking at the layout diagram backwards in which case, maybe the new transistors are in wrong and that is my problem. Thoughts?

The zener diode D8 is in the same orientation as it was on the original board and correct according to the layout diagram.
 

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The leg pinout on the new transistors are going to be different in just about ALL cases on the 1010 P.S. Board . Putting NTE transistors in there is really asking for trouble. They aren't designed to replace 1 or 2 specific transistors, they make them so they would just barely replace about 30-40 transistors and not one of them completely. Quality control is not good, and they brand what they get from low grade suppliers. Fairchild and ONSEMI (old Motorola) from a reliable supplier are about as bullet proof as you can get. In 99.9999940% of the time the fairchilds and ONSEMI's cost less too. Leg pinouts for the old (factory) transistors are listed on the schematics and parts lists in the manual.

The board looks good. Nicely done. I'm a little leary about what looks like a solder bridge in the lower left hand corner, that has the yellow circle. Looks like the trace from R-10 is touching the trace to Q5 collector/Q4 collector. I blew it up quite large and it does look like it's touching.

1010 ps board.jpg
 
Zeb, On MTF's 1250 list it says the -KSC1845FTA is a replacement for the 2SC869 (power amp). Above you list the 2383 as a replacement. Is the 2383 more "rugged"?
Bob
 
I think I should back up the bus and give you a little background. This unit belongs to a young man who I think wants to dabble in this field a little but not sure how far he wants to go. He brought me the board and said nobody wanted to work on it and although I teach DC electrical (truck and automotive) for a living, I dabble in electronics on the side. I can find my way around fairly well but sometimes need a kick in the right direction which is why I am here right now. The young man had started in on this and I think from the pictures it started out as something simple, and then he went and recapped the board and replaced all the transistors with the NTE units. When I got the board, it was badly damaged so I decided to scrap the board and build a new one. Thank you for the compliments, I was a little leary and very rusty at it but it turned out okay.

Footnote: There is no solder bridge between those two points. I had it under my USB microscope and examined it very closely. I also took a continuity test to back up my findings. All good.

So from what I am reading, should I pull the transistors and replace them with something else. If so, I use Digi-key quite a lot. Can I get them from there? Also, he has chosen random caps from ??? and I like to use low ESR caps because that is what I use when I repair monitors and TV's. Any thoughts on that?

Thanks guys for your help. All good. I appreciate it. Being on this thread makes me want to get into vintage stereos again. Very cool stuff. I have an old Pioneer SX-5 as well that I bought when I was a kid. Crackles now but I think that is just in the volume control. Another day. Need to get this one out of the way first.
 
Off the Thread; Rugged is a good description. The specs on the KSc2383's are slightly higher than the KSC1845's, yet the Vce are almost equal. The choice of transistor placements in the particular sets are from those who are experienced in the circuit structure and capabilities (Mostly from MTF, but Watt, Echo, Matt, and Rick are the guys you can trust for good solid transistor selections). When I'm troubleshooting I'll horse a larger equivalent in if I am out of stock to get the set running and check for other issues I may need parts for.
 
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Zeb, Good explanation. Did some thinking after reading your response. On the 1250 power amp board, that 869 is for the protection so unless I'm interpreting the schematic wrong, it's not under a heavy load/use or stress. Under more load/stress/use then your 2383 would make sense.
Again, good explanation.
Bob
 
Okay we are back. I have the unit in my hands and have done my initial testing. Here are the results on the power supply board.
Pin 1 = 62.1 VAC
Pin 2 = 62.1 VAC
Pin 3 = 18.5 VAC
Pin 4 = 18.5 VAC
Pin 5 = 6.9 VAC
Pin 6 = 7.02 VDC
Pin 7 - Ground 0.0 VDC
Pin 8 = 1.85 VDC
Pin 9 = -21.2 VDC
Pin 10 = -82.9 VDC
Pin 11 = -43.6 VDC
Pin 12 = 0.0 VDC
Pin 13 = 0.9 VDC
Pin 14 = 2.4 VDC
Pin 15 = -12.8 VDC

We definitely have some issues going on here. Where to start? I am thinking I take out these NTE substitutes and put in the proper replacements from Mouser or Digikey.

Here are the B-C-E readings from all eight transistors.
Q1 B-C-E = 3.0VDC/2.4VDC/83.9VDC
Q2 B-C-E = 3.5/84/3.0
Q3 = 0.7/3.5/0
Q4 = -43.9/-82.6/-82.7
Q5 = -36.3/-83.7/-44.8
Q6 = -37.0/-36.3/-36.2
Q7 = 2.2/24.0/1.7
Q8 = 1.5/2.1/1.0

I am thinking problem in Q4 - Q5 area?

EDIT: I am thinking you might be right about that trace. Those voltages are all the same. Good eye. I will check that out.
 
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The positive reg Q1, and Q2 are not getting the +DC from the rectifier.
And double check the leg placements of all transistors.
Get rid of the NTE junk or you'll be making another trip. Seriously!
All the mouser replacements are ECB but the board has Q2 and Q3 silk screened where they will have the collector leg forward, Be really careful of them. If their installed correctly, they will face the heatsink.
 
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