a new Pioneer SX1010 admirer

G

graftdesign

Active Member
Hey guys. Long time lurker and not much of a poster.

I guess I was excited with my new acquisition.. a pretty minty SX1010 so I had to post.

I love this unit. It sounds very articulate, authoritative, powerful and makes beautiful music. I wasn't really into Pioneers but can honestly say this is going to turn me into a fan. These things are pretty impressive considering I had some pretty nice gear running my speakers prior to this (Accuphase C200 and vintage restored SONY TA3000F amp) but this Pioneer really holds its own. I'm not going to say it sounds better, but it really gives the other gear a run for their money and to me sounds at least as good and in some respects better (bass).

The seller told me that the later model SX1010's had a redesign of the faulty PS board that mitigated the heat issues associated with these. Is that true? I was going to address that but this unit appears to need nothing at the moment.

Here's some pics...
 

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I am jealous. My 1010 has been getting worked on by another AK member since January. Hopefully I will have it back and working one day soon.
 
The amp boards have had factory changes but not the PS. At least I haven't seen any and I have done more than a few 1010's.
 
zebulon1 said:
The amp boards have had factory changes but not the PS. At least I haven't seen any and I have done more than a few 1010's.
Click to expand...

Oh, I think you are correct. I now remember the seller saying something about the amp board being changed. I think he said it was to mitigate the heat issue but I'm not 100% sure that's correct. I wonder why they didn't put the heat sinks on the outside on these.
 
The PS's do suffer two things. Heat dissipation but it's mitigated by MTF's upgraded component list. Some guys have installed small finned self adhesive heatsinks which I have used. Second: Transportation related damage when the bottom cover pushes against the PS heatsink and cracks the board in half.
 
graftdesign said:
Hey guys. Long time lurker and not much of a poster.

I guess I was excited with my new acquisition.. a pretty minty SX1010 so I had to post.

I love this unit. It sounds very articulate, authoritative, powerful and makes beautiful music. I wasn't really into Pioneers but can honestly say this is going to turn me into a fan. These things are pretty impressive considering I had some pretty nice gear running my speakers prior to this (Accuphase C200 and vintage restored SONY TA3000F amp) but this Pioneer really holds its own. I'm not going to say it sounds better, but it really gives the other gear a run for their money and to me sounds at least as good and in some respects better (bass).

The seller told me that the later model SX1010's had a redesign of the faulty PS board that mitigated the heat issues associated with these. Is that true? I was going to address that but this unit appears to need nothing at the moment.

Here's some pics...
Click to expand...

I picked up my 1010 a few weeks back. I agree, they are pretty impressive.
 
Pioneer updated the amp board by relocating one of the two STV-3 diodes from the driver stage heatsink to the output heatsink helping the amp better stabilize the heat related output current control. I think there was three different mods through out the production run. Maybe even four. The amplifier doesn't really run that hot just the PS. Mostly due to its location.

One of the all time classic receivers.
 
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Thanks zebulon:

I think my excitement on this unit is short lived. I turned the unit on this morning and after about a half hour of pleasurable listening I get a very startling and loud crackle and pop on my left speaker. It scared the hell out of me cause the unit wasn't playing very loud at all.

There's definitely an issue with this unit... perhaps the dreaded PS issue? Anyway, I guess I have to set the unit aside and out of rotation until I get it sorted. I think I purchased someone else's problem now that I think about it. Was hoping to enjoy this unit for a while.

I guess that's always a risk with these vintage pieces.
 
Most likely the 2sc1451's in the AMP BOARD are letting go. And when they do, it's CATASTROPHIC! Best not to run it until it's been repaired. There are 2 of them on the 1010, 1 ea on the amplifier boards. These are #1 on MTF's TOP TEN WANTED List. #'s 2 & 3 are the 2sa725 and 726. You'll find these thruout all the eq and preamp/control/amp boards. Replace them also.

2sc1451 replace with KCS3503
2sa725/726 replace with KSA992

Be aware that the pinout's WILL BE DIFFERENT from the originals. So download the Datasheets, and correlate them with the MARKED HOLES for the legs on the boards. 6 ways to install, only 1 is correct.

Also note that the bias voltage should be 50mv NOT 100mv as stated in the manual. PIONEER Engineers did the math wrong.....(they should have gotten their $$$ back from college).
 
Thanks Larryderouin:

Yeah, I think i will change the Transistors out that you mentioned along with updating the PS board. I did read about the orientation being different and how you have to twist the legs into their respective holes. I'll just have to be extra careful when I put the new ones in. It can get confusing working from the underside of a PC board. I'll have to compare the E,C,B with the schematic.... but then aren't those (schematics) sometimes wrong? Hopefully there will be something on the board where I can tell where the E,C,B goes.

I annoy myself sometimes. What I thought was a great purchase turned out to be another headache I don't need....
It's so hard to pick a vintage unit sometimes. It worked great at the sellers place before I bought it ... and then just a few hours later this happens.

different
larryderouin said:
Most likely the 2sc1451's in the AMP BOARD are letting go. And when they do, it's CATASTROPHIC! Best not to run it until it's been repaired. There are 2 of them on the 1010, 1 ea on the amplifier boards. These are #1 on MTF's TOP TEN WANTED List. #'s 2 & 3 are the 2sa725 and 726. You'll find these thruout all the eq and preamp/control/amp boards. Replace them also.

2sc1451 replace with KCS3503
2sa725/726 replace with KSA992

Be aware that the pinout's WILL BE DIFFERENT from the originals. So download the Datasheets, and correlate them with the MARKED HOLES for the legs on the boards. 6 ways to install, only 1 is correct.

Also note that the bias voltage should be 50mv NOT 100mv as stated in the manual. PIONEER Engineers did the math wrong.....(they should have gotten their $$$ back from college).
Click to expand...
 
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I had the same issue crop up after a year. Except the crackling came from both sides. Turns out it was a cracked tone board. I saw it.
 
I have been babysitting Larry's rebuilt SX 1010 at my house for just over three years. He went thru it with a fine tooth comb. It sounds fantastic and hasn't burped once in that time. (Thanks again Larry.)

Follow Larry's lead and what looks like a headache now will turn into great sound reproduction very soon.
 
DrTim said:
I have been babysitting Larry's rebuilt SX 1010 at my house for just over three years. He went thru it with a fine tooth comb. It sounds fantastic and hasn't burped once in that time. (Thanks again Larry.)

Follow Larry's lead and what looks like a headache now will turn into great sound reproduction very soon.
Click to expand...


Well I did get to enjoy it for a few hours anyway and it sounded wonderful so I know it has potential. Too bad it was so short lived. A few hours of pleasure wasn't enough! :)
 
Decided I'm going to give fixing the SX1010 a shot. I'm very adept at soldering having built many electronic kits back in the day and recently many, many crossovers so I'm not a newbie per-se .. just new to recapping etc.

I have a very simple question regarding the plastic clips that hold the circuit boards. Do I just compress the ends with a needle nose and remove the PS board that way or do I have to access the clips from the other side and take apart a bunch of stuff to get at them? These things look pretty fragile and I would hate to break them or worse, crack the PC board. They look like they expand into the holes and prone to damage. Are new ones like these easy to get?

Photo attached.


Thanks guys.
 

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needle nose pliers is what i use. haven't broken any yet. but there has to be a better way. willing to bet pioneer had a special tool. someone chime in with a diy tool please. thinking a simple tube the right size would do ?
 
I think your making a science project out of this standoff thing. I don't blame you in a way. Learning to disassemble an old crusty set is a learned endeavor. Sears sells a small pliers set. One needle nose is bent at almost 90 degrees. Use that one at the mid section of the exposed standoff pin. Squeeze carefully checking for any elasticity left in the standoff pin. If it breaks then an order is made and more work is required. No getting around it. If its still workable squeeze and pull up on the board at the same time. Once you move the board past the sweet spot remove the pliers and completely lift the board from the pin. A good practice is to work all the pins a little it a time and walk the board out never putting to much bend in the board.
 
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