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Pioneer SX 1010 - Simple question about Output TR order

70smidfiguy

70smidfiguy

Active Member
Hello all,

I was attempting to replace the output transistors in my 1010, took a pic before I removed them but alas the pic has disappeared :(

Can someone advise me of the order of the output transistors?

For simplicity, if I'm facing the back of the receiver from left to right?

Many thanks for humoring my ignorance!

Thanks
 
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Trace the collector connections back to the power supply, the Positive Supply goes to the NPN transistors and the Negative supply goes to the PNP transistors.

Why are you replacing the output transistors?
 
Look at the full schematic of the receiver in the service manual.
You’ll see the outputs connected to the power amp boards.
Follow the wires from the outputs to the board pins.
Match them up.
Once you get familiar with the set in front of you and reading the scat you’ll figure it out.
Post an image of the complete heat sink with the outputs installed before you put power to it.

By the way, do you know how to use a DBT?
 
Yep I have a DBT, took output transistors out to test as one channel was not working. Purchased MJ201194/93 to replace existing.

I was looking for the visual verification but will trace through schematic.

Cheers
 
70smidfiguy said:
Yep I have a DBT, took output transistors out to test as one channel was not working. Purchased MJ201194/93 to replace existing.

I was looking for the visual verification but will trace through schematic.

Cheers
Click to expand...
Are the ones you took out blown are they?
 
70smidfiguy said:
Yes 1 x PNP and one NPN was blown, my component tester shows them as unknown part
Click to expand...
That'll do it.
Any idea what might have caused the failure?
have the driver boards been rebuilt?

Recently I did a major restoration on a SX1010 and the driver board is a potential point of failure with some of the old transistors used in that circuit.
The other one to have a look at is the regulated supply underneath, if that hasn't been done, I'd suggest getting in there and doing that too.
 
Power supply brd I redid the caps, with output trs out unit turns on fine.

Is there any chance you could save me some concern by tell me the output tr order for npn vs pnp? I simply dont want to make a mistake. (I almost always tale pics!)
 
Are you still needing an answer to your question? I believe I have this written down as I just finished replacing all 8 in a customers unit. Let me know and I can post pics if you need them.
 
I am and would be very grateful!

I'm sitting here with my new Tr's and would love to move on.

Anything would be great, even just a pic.

Thanks in advance.
 
We have told you how to confirm it, get your meter and measure from the collector back to the Main Filter caps. Not sure why you need a diagram it will take 5 mins to do what I already suggested earlier in the thread.
Collector to Positive Supply = NPN
Collector to Negative Supply = PNP.
Its that simple....
The collector is the body of the transistor, so find the terminal that connects to that and clip one end of you meter on to it, then try the Negative Supply cap, and then the Positive supply cap, which ever one gives you continuity, will tell you what polarity transistor goes there.
 
Not to piss anyone off but just for future reference, here is what I have from the unit in front of me. Feel free to correct any of my findings. Looking at it from the rear, the left board is the right channel power amp and the middle board is the left channel power amp. The order of the power transistors goes NPN, NPN, PNP, PNP.............PNP, PNP, NPN, NPN. I think if I am correct, it is Q3,Q4,Q8,Q7.....Q6,Q5,Q1,Q2. Again, from the rear, left to right.
Wire colors are:

Q3 Collector (9) Red, Emitter (15) Blue, Base (10) White/Green
Q4 Emitter (14) White/Yellow
Q8 Collector (12) Orange), Emitter (17) White/Brown, Base (13) Gray
Q7 Emitter (16) White/Black
NOTE: I am not putting collector and base in every second line as they are common to the one above it.
Q6 Collector (12), Emitter (17) Blue, Base (13) Violet
Q5 Emitter (16) White
Q1 Collector (9), Emitter (15) Blue, Base (10) Green
Q2 Emitter (14) Yellow

As kevzep mentioned above, best to meter it out to confirm my findings but this should be the correct order.
I found it is always worth a few minutes of work to just take some pictures and keep a file of them so that you can refer back to them later. Makes life a lot easier. Good luck with your unit
 
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