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Pioneer SX-535 re-cap with pics

leesonic

leesonic

Captured on security camera...
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Funny how threads have a way of mutating. My crackly Pioneer SX-535 thread has mutated into a full re-cap of the thing.

This first picture shows how advancement in capacitor technology has made all of the caps that much smaller. This caused the greatest problem with the main power supply caps, which required a "MacGyver" type solution. Caps used were Nichcon KW series.

PioneerSX-535recap00.jpg


Here is the power supply board before and after. Those caps look a lot smaller don't they?

PioneerSX-535recap01.jpg


PioneerSX-535recap02.jpg


PioneerSX-535recap03.jpg


Next up was the replacement of the two main power supply caps. As the replacements were a lot smaller than the originals, they wouldn't fit inside the mounting brackets. What I did was take a couple of rubber lined P-clips, straighten the mounting tabs out, and use these to clamp the new caps. I formed the clips around a 1/2" socket first, just to make sure they were as round as I could get them, so they wouldn't crush the cap.

PioneerSX-535recap04.jpg


PioneerSX-535recap05.jpg


Next up was the power amp board. The little transistor circled in yellow was responsible for the crackling, and also for the huge DC offsets when the receiver was first turned on. I plan to replace all these transistors.

PioneerSX-535recap06.jpg


PioneerSX-535recap07.jpg


After all these replacements, I powered the receiver up, and it sounds really great now, no crackling at all.

Watch this space for replacement of the caps on the control board and tuner board.

Lee.
 
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Nice job!

Now I am curious. I had a friend help me replace a bad tape monitor button on a Pioneer RG-2. You know... the long switch with about 12 prongs per side. He used a metal braid to remove the old solder which I think I could do. My question is: Are replacing these caps about the same process...if not maybe a little easier? I would love to try my hand at this if I could be sure to get the right replacement caps. Is there a certain way these caps need to be installed and how do you tell? I have mostly Pioneer gear.

Thank you..... I loved the before and after pics...Well done!
 
Bstable said:
Now I am curious. I had a friend help me replace a bad tape monitor button on a Pioneer RG-2. You know... the long switch with about 12 prongs per side. He used a metal braid to remove the old solder which I think I could do. My question is: Are replacing these caps about the same process...if not maybe a little easier? I would love to try my hand at this if I could be sure to get the right replacement caps. Is there a certain way these caps need to be installed and how do you tell? I have mostly Pioneer gear.

Thank you..... I loved the before and after pics...Well done!
Click to expand...

You could use a solder braid, yes. I prefer to use a solder sucker, or desoldering pump, something like this. Replacing the caps would be easier than a switch since there are only two wires, not 12 prongs. But there are more of them.

The caps most people replace are the electrolytic ones. Without getting into too much detail, these are the ones that deteriorate with age. They are polarized, which means they only go in one way. Get them wrong, and they WILL explode, with quite considerable force especially the larger ones. The Pioneer receiver I'm working on has the + terminal marked on the component side of the board, but I always mark on the track side which goes where. The capacitors have a stripe on them, or a black terminal, indication the minus side.

Lee.
 
Did the control board and phono equalizer today. Sometimes it's difficult getting the same camera angle for the before and after pics. I forgot to take a picture after replacing the transistors, but I did these as well.

PioneerSX-535recap08.jpg


PioneerSX-535recap09.jpg


Here is the phono equalizer board. Keen eyed observers will also notice I replaced the transistors as well. The original ones have the black corrosion on their legs, and this is what made the receiver crackle in the first place (although this was caused by a transistor on the power amp board).

PioneerSX-535recap10.jpg


PioneerSX-535recap11.jpg
 
Thank you leesonic for the info...you have inspired me, and your before and after pics are excellent. Keep us posted, and of course, let us know about the before and after sound.
 
Bstable said:
Thank you leesonic for the info...you have inspired me, and your before and after pics are excellent. Keep us posted, and of course, let us know about the before and after sound.
Click to expand...

Oh, I can already tell you about the sound, and I'm still not finished yet (have to do the tuner board, and then I might replace all the small signal transistors on the power amp board).

I connected it up last night, and had a listen. Obviously, it's hard to do a real comparison, you would really need two receivers side by side, one re-capped and the other on the old caps. What I do remember is the bass seemed to sound a little soft before, if I remember correctly.

Well, last night, it was thumping through my Advent Legacy 2s. On a track with a drum machine (like "Turn it around" by Gino Soccio, this YouTube link should work), the bass drum beat has more of a click to it than a real drum. It sounds clichéd, but that click kick was there like I don't remember before.

Then I tried some female vocals, "Say I'm your number one" by Princess, probably the best record ever to come out of the awful Stock Aitken Waterman "hit machine" in the 1980/90s. Her vocals were clear and soaring, and the bass line sounded solid. One interesting thing, I have this track on a CD that was recorded from the 12" single. I put the record on and the CD, and the phono input was louder than the CD. I'm pretty sure, when I recorded the tracks on there, I boosted the volume levels using the Maximise feature on the Goldwave software.

Finally, I tried "Your Song" by Elton John (everyone knows that one). The soundstage got bigger as more instruments came into the mix, but the vocals were slap bang in the middle like they should be.

Note to self : must get those Advents up off the floor...

Lee.
 
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I would like to just say, reading this and your thread on the 901's, not only very informative but the photography is very precise. Bravo mate.
 
Here is the tuner board before and after pics :

PioneerSX-535recap12.jpg


PioneerSX-535recap13.jpg


So, to re-cap (no pun intended), I have replaced all the electrolytic caps in this baby. I have also replaced the small signal transistors in the control board, the phono EQ board, and the first four in the signal path on the power amp board.

Phew! Onto the next project...
 
A couple notes about the repair process. When using the braid, be very careful. I use it alot, but it is pretty easy to mess it up. People tend to use too much heat and then cook the board or lift the run(the circuit). Practice on a peice of junk first. Use a good flux to help transfer the heat and keep the solder clean. Make sure your solder tip is clean. After you have wicked the solder, clean the area with alcohol before trying to remove the part. You can get away with doing some of this stuff halfway, but attention to detail is very important with electronics repair. I too prefer a solder sucker, but I got spoiled with a good Pace unit when I was doing this stuff daily.
 
I checked out the JVC thread. That JVC has a nice clean look. Again, you take some mighty fine pics.

What was the total cost of the caps for the Pioneer? I just want to get a ball park figure for my first project, which will be a SX-680. I'm guessing (dangerous) that it will be similar in cost.
 
Bstable said:
I checked out the JVC thread. That JVC has a nice clean look. Again, you take some mighty fine pics.
Click to expand...

Thank you. It doesn't help wrestling with a camera that makes me want to throw it over the other side of the room. Actually, it's not the camera that's the problem (it's a Nikon Coolpix L100), it's the crappy rechargeable batteries. These Duracells never last long when they were new, and they're even worse now. I need to do some research and find some Sanyo Eneloops.

Bstable said:
What was the total cost of the caps for the Pioneer? I just want to get a ball park figure for my first project, which will be a SX-680. I'm guessing (dangerous) that it will be similar in cost.
Click to expand...

Probably no more than $30. The project actually started because I hate making orders to Mouser, Parts Express or Allied Electronics for 25 cents, and then paying $10 for shipping. I only needed one transistor to fix the crackling problem, but since the shipping was going to be a lot more, I decided to order the caps as well.

Lee.
 
I see that you left the original tantalum bead caps in place on the phono preamp board. They're probably not defective, but the preamp might very well sound cleaner with some good low-leakage aluminum lytics instead.
 
This thread gives me confidence in my upcoming recap! Doing a SX-580 as soon as my caps arrive. Your 535 looks great. The SX-x3x series is a great looking run. Funny how much smaller modern caps are than original stuff, I have a feeling the 2 power caps I ordered for mine are going to be much smaller, and the originals are small. Its going to look kind of sad now. But, hopefully, sound better at the same time.
 
That receiver should be on the "most beautiful gear" thread, but then again, I am a sucker for Pioneer gear in general. That blue dial really does it for me. :drool:
 
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