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SX phono stage

Jovinyl

Jovinyl

AK Subscriber
Subscriber
Does the SX series have a known issue with phono stage, I am trying to find route of problem which the main culprit could be turntable. I have SX 737 and SX 950 all functions work except the phono stage has out of control static on both units. at one time I had turntable hooked up to SX 737 it was fine for awhile though I hardly used it. Last time I went to use turntable, when I switched to phono, nothing but terrible static. I still have DVD/CDplayer and VHS connected and all is fine, took table out, still static just when I switched to phono. Wanted to hear 12" 45 so I hooked turntable to SX 950 that I had CD + Cassette connected to. All sounded good, been a few weeks I wanted to hear a cassette tape. Turn on 950 still in phono stage and problem with 737 I was now having with 950 which is also the first time I had TT connected. The turntable played fine when I used it and was turned of when done. I just left it connected as everything worked and sounded good until I wanted to use system today. I noticed nothing wrong with the turntable as it worked as it should. Could It be because both systems have'nt had a signal pass through it in maybe a year or more?
Thanks
 
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sx737 sx950 awf011 phono board rebuild

The sx-737 and sx-950 use the same phono board, AWF011.

The 2sa725 transistors on them tend to get noisy and fail with age, the failure then hurts the power supply.

Replacing the transistors and electrolytic caps brings them back to full glory.

It's an easy and inexpensive DIY fix.

This thread handled the same problem:
http://www.audiokarma.org/forums/showthread.php?p=2017537&highlight=AWF011#post2017537

This thread shares insights on transistor lead arrangements (the replacements are a different lead arrangement than the originals)
http://www.audiokarma.org/forums/showthread.php?p=2145019&highlight=AWF011#post2145019

and yet another thread:
http://www.audiokarma.org/forums/showthread.php?p=1871074&highlight=AWF011#post1871074


these are the replacement parts:

From mouser.com
Q1, Q2 : 512-KSA992FBU (low noise)to-92 ecb 120v .05a .5w 100mhz 150-800hfe $0.06 ea
Q3, Q4, Q5, Q6: 512-KSC1845EBU (low noise)to-92 ecb 120v .05a .5w 100mhz 150-800hfe $0.06 ea
C1, C2: 1uf 25v 647-UPW1H010MDD 1uf 50v $0.14 ea
C7, C8: 330uf 6v 647-UPW0J331MED 330uf 6.3v $0.24 ea
C11, C12: 3.3uf 25v 647-UPW1H3R3MDD 3.3uf 50v $0.14 ea
C17: 100uf 35v 647-UPW1H101MPD 100uf 50v $0.36 ea
C18: 220uf 25v 647-upw1h221mpd 220uf 50v $0.48 ea

The prices are from July 2008....
edit: I just checked stock, and prices, and some prices (the list's prices are updated) have come DOWN!!
 
Thank You Mark. I went to mouser.com. I see that I just enter part# it comes up. This will be my first attempt at something like this. What I do not understand is the Q1,Q2 >Q6 and the C1,C2 etc. part of the list. I am thinking of ordering the parts for both units. Probably more than I'll need, might as well start a parts bin. I will have the parts on hand when I'm ready to go for it.
 
Shot in the dark. let me see if I figured it out:


Q1, Q2 : 512-KSA992FBU (low noise)to-92 ecb 120v .05a .5w 100mhz 150-800hfe $0.06 ea (2)

Q3, Q4, Q5, Q6: 512-KSC1845EBU (low noise)to-92 ecb 120v .05a .5w 100mhz 150-800hfe $0.06 ea (4)

C1, C2: 1uf 25v 647-UPW1H010MDD 1uf 50v $0.14 ea (2)

C7, C8: 330uf 6v 647-UPW0J331MED 330uf 6.3v $0.24 ea (2)

C11, C12: 3.3uf 25v 647-UPW1H3R3MDD 3.3uf 50v $0.14 ea (2)

C17: 100uf 35v 647-UPW1H101MPD 100uf 50v $0.36 ea (1)

C18: 220uf 25v 647-upw1h221mpd 220uf 50v $0.48 ea (1)

Would the numbers in ( ) after price, be the quanity of each part I need per board?
 
Jovinyl said:
Shot in the dark. let me see if I figured it out:


Q1, Q2 : 512-KSA992FBU (low noise)to-92 ecb 120v .05a .5w 100mhz 150-800hfe $0.06 ea (2)

Q3, Q4, Q5, Q6: 512-KSC1845EBU (low noise)to-92 ecb 120v .05a .5w 100mhz 150-800hfe $0.06 ea (4)

C1, C2: 1uf 25v 647-UPW1H010MDD 1uf 50v $0.14 ea (2)

C7, C8: 330uf 6v 647-UPW0J331MED 330uf 6.3v $0.24 ea (2)

C11, C12: 3.3uf 25v 647-UPW1H3R3MDD 3.3uf 50v $0.14 ea (2)

C17: 100uf 35v 647-UPW1H101MPD 100uf 50v $0.36 ea (1)

C18: 220uf 25v 647-upw1h221mpd 220uf 50v $0.48 ea (1)

Would the numbers in ( ) after price, be the quanity of each part I need per board?
Click to expand...

Looks spot on to me. This might sound trivial, but get yourself a new or have a very clean tip for your soldering iron. It helps out tremendously. Needlenose pliers also come in handy because those capacitors get HOT. Trust me on that one :D
 
Ordered Parts. :thmbsp: A few more items I need to get. I think the shack will have them. Got to solve data base mystery now.
 
Jovinyl said:
Shot in the dark. let me see if I figured it out:


Q1, Q2 : 512-KSA992FBU (low noise)to-92 ecb 120v .05a .5w 100mhz 150-800hfe $0.06 ea (2)

Q3, Q4, Q5, Q6: 512-KSC1845EBU (low noise)to-92 ecb 120v .05a .5w 100mhz 150-800hfe $0.06 ea (4)

C1, C2: 1uf 25v 647-UPW1H010MDD 1uf 50v $0.14 ea (2)

C7, C8: 330uf 6v 647-UPW0J331MED 330uf 6.3v $0.24 ea (2)

C11, C12: 3.3uf 25v 647-UPW1H3R3MDD 3.3uf 50v $0.14 ea (2)

C17: 100uf 35v 647-UPW1H101MPD 100uf 50v $0.36 ea (1)

C18: 220uf 25v 647-upw1h221mpd 220uf 50v $0.48 ea (1)

Would the numbers in ( ) after price, be the quantity of each part I need per board?
Click to expand...

Absolutely correct, for example you would buy two ksa992's per board
Look up the AWF011 board in the sx-737 or sx-950 service manual, in which it will identify two transistors and their positions as Q1 and Q2 that are originally 2sa725's , Then one replacement ksa992 (the transistor will probably be marked: "a992") will go in position Q1 and the other replacement ksa992 will go in position Q2.

notice that a's replace a's , and thus c's replace c's.....

Also you notice in THE OTHER THREADS:

2sa725 to-92 BCE 50v 0.1a 0.2w 100mhz 500hfe watch out, the replacement is ecb
2sc1313 to-92 BCE 50v 0.1a 0.2w 150mhz 350hfe watch out, the replacement is ecb

512-KSA992FBU (ln)to-92 ecb 120v .05a .5w 100mhz 150-800hfe $0.06 ea
512-KSC1845EBU (ln)to-92 ecb 120v .05a .5w 100mhz 150-800hfe $0.06 ea

Q1 is originally a 2sa725 with an bce lead arrangement (left to right - looking at the transistor's lettering)
while the replacement ksa992 is an ecb lead arrangement (left to right - looking at the transistor's lettering)

Thus you have to compensate for the reversed lead arrangement when installing it - usually by facing the flat face with the lettering in the opposite direction.
 
Thanks.
When I get all I need for the task, I'm going for it. I'll start with the 737. Can't seem to get into database. Where can I get the better copy of a service manual. I odered one online for a marantz once and it was a sloppy copy and I don't remember where or who. I just don't want to buy from them again.
 
The database is accessable. Take your time and read the whole first post by Njord and follow instructions.
You'll figure it out. Lots of good manuals there.
 
The database is having a problem - I couldn't get the pioneer page a short time ago.


edit: wheeeew Lee , you scared the bejibbers outta me.....

If the database stays down, I can upload the two manuals to sendspace and send you the download link.
 
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