Just got a Pioneer sx-1050 Yay! Would like to know if there are any known issues.

I just aquired my second beastie ever last night, A Pioneer SX-1050! I'm so happy with my purchase! Seller was great and everything.
Unit is in great shape just needs a little deoxit in the volume and balance area, but not much. Of course, I'm going to deox everything anyway.
Everything works perfect, switches, speaker channels, lights, meters, all controls. Cosmetically in great shape: wood case nice and sharp no peices missing or anything, face is clean and scratch free and shiny, fair amount of dust in the case vent so I will be popping the hood to clean it inside....carefully as always. Unit sounds great.

I'll be popping over to the docs section later to find the manuals. I'd like to know if there are any "known issues" I should be aware of.

Thank you.

~Eric

Welcome to the club, enjoy it

not really, just the usual, recap (maybe retransistor) the baked power supply and protection circuits for reliability, the protection already HAS the "extra diode" across the coil for longevity.

There are a pair of 2sa725's in the flat amp that could get noisy, but don't seem to be run hard enough to do it a lot in this model.

recap everything else for the best sound..... when you're feeling feisty....

markthefixer said:

not really, just the usual, recap (maybe retransistor) the baked power supply and protection circuits for reliability, the protection already HAS the "extra diode" across the coil for longevity.

There are a pair of 2sa725's in the flat amp that could get noisy, but don't seem to be run hard enough to do it a lot in this model.

recap everything else for the best sound..... when you're feeling feisty....

Click to expand...

Thanks Mark. Sounds like I will do the "if it's not broken don't fix it" for now. "Baked power supply and protection circuits"? The thing works fine, if those things were baked wouldn't not work? That said though, I have not looked inside yet.
I've lost all I was taught in electronics many moons ago (except basic soldering) and have never done a recap or anything like that. I'm really scared of hurting a peice of gear..poor things. That said though I fully trust you and the other experts here and I know you guys will guide me every step of the way as long as I do exactly what I am told and no more and not jump ahead should I get brave enough to do it. (I know I have a Yamaha CR-2020 with the recall on the power supply board thingy I may face someday, but I'm taking the same approach: not broken, don't fix, wait until the problem shows up).

Long term poor ventilation around the receiver could trap heat inside, the power supply board will show variable visible discoloration, transistor metal on the power transistors will look blackened, the transistor epoxy will gray a bit...

We can talk you through it. Just look at the old steve_1050 thread, that got involved but with deliberate care had a very happy ending.

markthefixer said:

Long term poor ventilation around the receiver could trap heat inside, the power supply board will show variable visible discoloration, transistor metal on the power transistors will look blackened, the transistor epoxy will gray a bit...

We can talk you through it. Just look at the old steve_1050 thread, that got involved but with deliberate care had a very happy ending.

Click to expand...

Thanks again Mark. I'll try to pop the hood this weekend and take a look. Then if things need to be done we can go from there when I'm ready.

I am posting my list that I have put together. I am also Recapping my
2nd SX-1050. Your in Great Hands here and Ask Questions...

CohibaJoe said:

I am posting my list that I have put together. I am also Recapping my
2nd SX-1050. Your in Great Hands here and Ask Questions...

Click to expand...

Hey thanks Joe, appreciate it.:thmbsp:

I had to update the List again. Missed for Power Supply Circ. A 220uf 100v
cap that replaces 220uf 80v.

That list has TANTALUM capacitors!!!! what else I don't know, saw some digikey numbers.

sheesh, you guys are killin me.... bench time is suffering too

I posted a list for the 1050 a while back, I JUST ran it into the BOM entry and a few are backordered, so I'll look into it...

markthefixer said:

That list has TANTALUM capacitors!!!! what else I don't know, saw some digikey numbers.

sheesh, you guys are killin me.... bench time is suffering too

I posted a list for the 1050 a while back, I JUST ran it into the BOM entry and a few are backordered, so I'll look into it...

Click to expand...

YES. I was going to post what I consider to be a known issue. And that is the TANTALUM capacitors.

Wanna improve the sound by a very hearable order of magnitude? Replace the tantalums with quality electrolytics. spend $4 on replacement caps. If these were the only caps you changed, I am quite confident you would be very happy with the result. The SX1050 is an excellent design, in many ways one of the best Pioneer ever made. However, the unit is crippled by the tantalums. As are the other Pioneer TOTL receivers.


Mark, I don't know how you do it. Where do you find the time to make and upgrade all the lists you post here? I want you to know I appreciate it. You da man. Now, could I get you interested in Sansui's? We could use some parts lists over on that list.

Trnsfmr said:

Mark, I don't know how you do it. Where do you find the time to make and upgrade all the lists you post here? I want you to know I appreciate it. You da man. Now, could I get you interested in Sansui's? We could use some parts lists over on that list.

Click to expand...

I'm dancing with burnout...

Did you ever see the movie "The Prestige"? Magicians ? Nikola Tesla? "getting your hands dirty?"

Know what the plot twist was?

spoiler alert:
























Need one mtf for Pioneer, one for Sui's, One for Marantz, and so forth...

edit - that's also why I save the intermediate steps of my work, grab the middle, update and forge ahead.

current recap master list sx-1050

markthefixer said:

That list has TANTALUM capacitors!!!! what else I don't know, saw some digikey numbers.

sheesh, you guys are killin me.... bench time is suffering too

I posted a list for the 1050 a while back, I JUST ran it into the BOM entry and a few are backordered, so I'll look into it...

Click to expand...

updated, just verified no backorders in list...

board cap uf v desig uf v part number
power supply reg-a
awr-103 c1 220 80 cea 220 100 647-UHE2A221MHD
awr-103 c3 47 16 cea 47 35 647-UPW1V470MED
awr-103 c6 47 35 cea 47 35 647-UPW1V470MED
awr-103 c7 10 35 cea 10 50 647-UPW1H100MDD
awr-103 c8 1 50 cea 1 100 647-UPW2A010MDD
awr-103 c9 220 80 cea 220 100 647-UHE2A221MHD
awr-103 c12 47 16 cea 47 35 647-UPW1V470MED
awr-103 c14 47 35 cea 47 35 647-UPW1V470MED
awr-103 c15 100 35 cea 100 35 647-UPW1V101MPD
awr-103 c16 220 25 cea 220 25 647-UPW1E221MPD
awr-103 c17 47 10 cea 47 35 647-UPW1V470MED
awr-103 c20 100 25 cea 100 35 647-UPW1V101MPD
awr-103 c22 47 10 cea 47 35 647-UPW1V470MED
awr-103 c23 2.2 50 cea 2.2 50 647-UPW1H2R2MDD
awr-103 c24 220 16 cea 220 25 647-UPW1E221MPD

surge suppressor
awx-098 c1 10 63 cea 10 100 647-UPJ2A100MED

power supply -b
awr-104 c9 470 100 ach-038 470 100 647-UPW2A471MHD
awr-104 c10 470 100 ach-038 470 100 647-UPW2A471MHD
awr-104 c11 2200 25 cea 2200 35 647-UPW1V222MHD

protection
awm-090 c1 0.22 25 cssa 0.22 50 598-DSF050J224
awm-090 c2 0.22 25 cssa 0.22 50 598-DSF050J224
awm-090 c3 470 6 cea 470 10 647-UPW1A471MPD
awm-090 c4 470 6 cea 470 10 647-UPW1A471MPD
awm-090 c5 2.2 50 cea 2.2 50 647-UPW1H2R2MDD
awm-090 c6 47 50 cea 47 50 647-UPW1H470MED

power amp
awh-047 c1 0.68 25 csza 0.68 50 667-ECQ-V1H684JL
awh-047 c2 0.68 25 csza 0.68 50 667-ECQ-V1H684JL
awh-047 c5 10 16 cea 10 50 647-UPW1H100MDD
awh-047 c6 10 16 cea 10 50 647-UPW1H100MDD
awh-047 c25 470 6 cea 470 10 647-UPW1A471MPD
awh-047 c26 470 6 cea 470 10 647-UPW1A471MPD
awh-047 c27 470 6 cea 470 10 647-UPW1A471MPD
awh-047 c28 470 6 cea 470 10 647-UPW1A471MPD

filter amp
awm-089 c3 4.7 25 csza 4.7 25 647-UKL1E4R7KDDANA
awm-089 c6 10 25 csza 10 50 647-UKL1H100KDDANA
awm-089 c9 4.7 25 csza 4.7 25 647-UKL1E4R7KDDANA
awm-089 c12 10 25 csza 10 50 647-UKL1H100KDDANA

control amp
awg-041 c1 4.7 25 csza 4.7 25 647-UKL1E4R7KDDANA
awg-041 c2 4.7 25 csza 4.7 25 647-UKL1E4R7KDDANA
awg-041 c3 4.7 25 csza 4.7 25 647-UKL1E4R7KDDANA
awg-041 c4 4.7 25 csza 4.7 25 647-UKL1E4R7KDDANA
awg-041 c11 2.2 25 ceanl 2.2 50 647-UKL1H2R2KDDANA
awg-041 c12 2.2 25 ceanl 2.2 50 647-UKL1H2R2KDDANA
awg-041 c13 2.2 25 ceanl 2.2 50 647-UKL1H2R2KDDANA
awg-041 c14 2.2 25 ceanl 2.2 50 647-UKL1H2R2KDDANA
awg-041 c17 100 16 ach-312 100 35 647-UPW1V101MPD
awg-041 c18 100 16 ach-312 100 35 647-UPW1V101MPD
awg-041 c19 2.2 25 ceanl 2.2 50 647-UKL1H2R2KDDANA
awg-041 c20 2.2 25 ceanl 2.2 50 647-UKL1H2R2KDDANA
awg-041 c27 2.2 25 ceanl 2.2 50 647-UKL1H2R2KDDANA
awg-041 c28 2.2 25 ceanl 2.2 50 647-UKL1H2R2KDDANA
awg-041 c29 2.2 25 ceanl 2.2 50 647-UKL1H2R2KDDANA
awg-041 c30 2.2 25 ceanl 2.2 50 647-UKL1H2R2KDDANA
awg-041 c33 100 10 ach-312 100 35 647-UPW1V101MPD
awg-041 c34 100 10 ach-312 100 35 647-UPW1V101MPD
awg-041 c35 2.2 25 ceanl 2.2 50 647-UKL1H2R2KDDANA
awg-041 c36 2.2 25 ceanl 2.2 50 647-UKL1H2R2KDDANA
awg-041 c37 100 16 ach-311 100 35 647-UPW1V101MPD
awg-041 c38 100 16 ach-311 100 35 647-UPW1V101MPD
awg-041 c39 100 16 ach-311 100 35 647-UPW1V101MPD
awg-041 c40 100 16 ach-311 100 35 647-UPW1V101MPD
awg-041 c43 10 25 csza 10 50 647-UKL1H100KDDANA
awg-041 c44 10 25 csza 10 50 647-UKL1H100KDDANA

flat amp
awg-040 c1 1 25 csza 1 50 647-UKL1H010KDDANA
awg-040 c2 1 25 csza 1 50 647-UKL1H010KDDANA
awg-040 c3 1 25 csza 1 50 647-UKL1H010KDDANA
awg-040 c4 1 25 csza 1 50 647-UKL1H010KDDANA
awg-040 c5 4.7 25 ceanl 4.7 25 647-UKL1E4R7KDDANA
awg-040 c6 4.7 25 ceanl 4.7 25 647-UKL1E4R7KDDANA
awg-040 c7 220 35 cea 220 35 647-UPW1V221MPD
awg-040 c8 220 35 cea 220 35 647-UPW1V221MPD
awg-040 c13 2.2 25 csza 2.2 50 647-UKL1H2R2KDDANA
awg-040 c14 2.2 25 csza 2.2 50 647-UKL1H2R2KDDANA
awg-040 c15 100 10 ceanl 100 10 647-UKL1A101KEDANA
awg-040 c16 100 10 ceanl 100 10 647-UKL1A101KEDANA
awg-040 c23 100 10 ceanl 100 10 647-UKL1A101KEDANA
awg-040 c24 100 10 ceanl 100 10 647-UKL1A101KEDANA
awg-040 c25 220 35 cea 220 35 647-UPW1V221MPD
awg-040 c26 220 35 cea 220 35 647-UPW1V221MPD

equalizer amp
awf-020 c1 4.7 25 csza 4.7 25 647-UKL1E4R7KDDANA
awf-020 c2 4.7 25 csza 4.7 25 647-UKL1E4R7KDDANA
awf-020 c5 220 35 cea 220 35 647-UPW1V221MPD
awf-020 c6 220 35 cea 220 35 647-UPW1V221MPD
awf-020 c9 220 10 cea 220 25 647-UPW1E221MPD
awf-020 c10 220 10 cea 220 25 647-UPW1E221MPD
awf-020 c17 33 35 cea 33 35 647-UPW1V330MDD
awf-020 c18 33 35 cea 33 35 647-UPW1V330MDD
awf-020 c21 10 35 ceanl 10 50 647-UKL1H100KDDANA
awf-020 c22 10 35 ceanl 10 50 647-UKL1H100KDDANA

tuner
awe-067 c35 100 16 cea 100 35 647-UPW1V101MPD
awe-067 c36 1 50 cea 1 100 647-UPW2A010MDD
awe-067 c38 10 16 ceanl 10 50 647-UKL1H100KDDANA
awe-067 c39 47 16 ceanl 47 25 647-UKL1E470KEDANA
awe-067 c40 100 16 cea 100 35 647-UPW1V101MPD
awe-067 c42 4.7 25 ceanl 4.7 25 647-UKL1E4R7KDDANA
awe-067 c43 10 16 ceanl 10 50 647-UKL1H100KDDANA
awe-067 c44 10 16 ceanl 10 50 647-UKL1H100KDDANA
awe-067 c47 1 25 ceanl 1 50 647-UKL1H010KDDANA
awe-067 c50 0.22 25 cssa 0.22 50 598-DSF050J224
awe-067 c51 1 10 cssa 1 50 647-UKL1H010KDDANA
awe-067 c52 3.3 10 cssa 3.3 50 647-UKL1H3R3KDDANA
awe-067 c54 220 16 cea 220 25 647-UPW1E221MPD
awe-067 c59 47 16 cea 47 35 647-UPW1V470MED
awe-067 c60 4.7 25 cea 4.7 50 647-UPW1H4R7MDD
awe-067 c64 10 16 cea 10 50 647-UPW1H100MDD
awe-067 c67 0.1 25 cssa 0.1 50 598-DSF050J
awe-067 c70 1 25 ceanl 1 50 647-UKL1H010KDDANA
awe-067 c71 0.1 25 cssa 0.1 50 598-DSF050J
awe-067 c72 0.47 50 cea 0.47 50 598-DSF050J474

main caps
none c1 22000 80 ach-056 22000
none c2 22000 80 ach-056 22000



bom: (verified no backorders):
647-UPW2A471MHD
647-UPW2A471MHD
647-UPW1V101MPD
647-UPW1V101MPD
647-UPW1V101MPD
647-UPW1V101MPD
647-UPW1V101MPD
647-UPW1V101MPD
647-UPW1V101MPD
647-UPW1V101MPD
598-DSF050J474
647-UPW2A010MDD
647-UPW2A010MDD
647-UPW1H2R2MDD
647-UPW1H2R2MDD
647-UPW1H4R7MDD
647-UPW1H100MDD
647-UPW1H100MDD
647-UPW1H100MDD
647-UPW1H100MDD
647-UPJ2A100MED
647-UPW1V330MDD
647-UPW1V330MDD
647-UPW1V470MED
647-UPW1V470MED
647-UPW1V470MED
647-UPW1V470MED
647-UPW1V470MED
647-UPW1V470MED
647-UPW1V470MED
647-UPW1H470MED
647-UPW1V101MPD
647-UPW1V101MPD
647-UPW1V101MPD
647-UPW1V101MPD
647-UPW1E221MPD
647-UPW1E221MPD
647-UPW1E221MPD
647-UPW1E221MPD
647-UPW1E221MPD
647-UPW1V221MPD
647-UPW1V221MPD
647-UPW1V221MPD
647-UPW1V221MPD
647-UPW1V221MPD
647-UPW1V221MPD
647-UHE2A221MHD
647-UHE2A221MHD
647-UPW1A471MPD
647-UPW1A471MPD
647-UPW1A471MPD
647-UPW1A471MPD
647-UPW1A471MPD
647-UPW1A471MPD
647-UPW1V222MHD
647-UKL1H010KDDANA
647-UKL1H010KDDANA
647-UKL1H2R2KDDANA
647-UKL1H2R2KDDANA
647-UKL1H2R2KDDANA
647-UKL1H2R2KDDANA
647-UKL1H2R2KDDANA
647-UKL1H2R2KDDANA
647-UKL1H2R2KDDANA
647-UKL1H2R2KDDANA
647-UKL1H2R2KDDANA
647-UKL1H2R2KDDANA
647-UKL1H2R2KDDANA
647-UKL1H2R2KDDANA
647-UKL1E4R7KDDANA
647-UKL1E4R7KDDANA
647-UKL1E4R7KDDANA
647-UKL1H100KDDANA
647-UKL1H100KDDANA
647-UKL1H100KDDANA
647-UKL1H100KDDANA
647-UKL1H100KDDANA
647-UKL1E470KEDANA
647-UKL1A101KEDANA
647-UKL1A101KEDANA
647-UKL1A101KEDANA
647-UKL1A101KEDANA
598-DSF050J
598-DSF050J
598-DSF050J224
598-DSF050J224
598-DSF050J224
647-UKL1H010KDDANA
647-UKL1H3R3KDDANA
667-ECQ-V1H684JL
667-ECQ-V1H684JL
647-UKL1H010KDDANA
647-UKL1H010KDDANA
647-UKL1H010KDDANA
647-UKL1H010KDDANA
647-UKL1H2R2KDDANA
647-UKL1H2R2KDDANA
647-UKL1E4R7KDDANA
647-UKL1E4R7KDDANA
647-UKL1E4R7KDDANA
647-UKL1E4R7KDDANA
647-UKL1E4R7KDDANA
647-UKL1E4R7KDDANA
647-UKL1E4R7KDDANA
647-UKL1E4R7KDDANA
647-UKL1H100KDDANA
647-UKL1H100KDDANA
647-UKL1H100KDDANA
647-UKL1H100KDDANA

I had put both TANTALUM capacitors:nono: and the replacement in the list. I will remove the TANTALUM capacitors from the list tonight.

CohibaJoe said:

I had put both TANTALUM capacitors:nono: and the replacement in the list. I will remove the TANTALUM capacitors from the list tonight.

Click to expand...

CJoe, Hey, there's way more than 2 (or two pairs) tantalums in there. I'd have to go check my box of caps from the 1050, but I think it was more like 20 or so. They start in the phono preamp and go all the way through. I'm away for the weekend on a friends computer, so I don't even have my schematics to look at, but if you want, I can tell you where they all are after I get home on Tue. AND, they are all in the signal path.

:tears:

Trnsfmr said:

CJoe, Hey, there's way more than 2 (or two pairs) tantalums in there. I'd have to go check my box of caps from the 1050, but I think it was more like 20 or so. They start in the phono preamp and go all the way through. I'm away for the weekend on a friends computer, so I don't even have my schematics to look at, but if you want, I can tell you where they all are after I get home on Tue. AND, they are all in the signal path.

:tears:

Click to expand...

The two tantalum caps he was talking about are the ones on his list, of which there were only two. Pioneer loved the little guys and thought they were slicker than c** s*** on a linoleum floor and used them all over. They were a bit off on that...

I WISH they weren't.... they have some desirable qualities, but the undesirable ones outweigh them - I even pull them from the power circuits of my Tektronix test equipment. I get MORE TEK test equipment cheap because of failed power supply bypass tantalum capacitors than anything else.

Trnsfmr said:

YES. I was going to post what I consider to be a known issue. And that is the TANTALUM capacitors.

Wanna improve the sound by a very hearable order of magnitude? Replace the tantalums with quality electrolytics. spend $4 on replacement caps. If these were the only caps you changed, I am quite confident you would be very happy with the result. The SX1050 is an excellent design, in many ways one of the best Pioneer ever made. However, the unit is crippled by the tantalums. As are the other Pioneer TOTL receivers.


Mark, I don't know how you do it. Where do you find the time to make and upgrade all the lists you post here? I want you to know I appreciate it. You da man. Now, could I get you interested in Sansui's? We could use some parts lists over on that list.

Click to expand...

Thanks for the additional info! Heck, the parts are so inexpensive it's worth going for the better caps.

PICS! NUDIE ALERT! Dirtiest receiver I've ever seen inside!

Ok, the first thing I need to do is clean the inside before I even power the thing up again. (Only powered it up at sellers).
As you will see in the pics this thing is a mess inside. Beat my sx990 in dirt hands down and I thought that was bad!

Questions about pics:
1) I hope that big round thing is the power supply/transformer and not a cap!
2) See the pic with the outer coating damage on one of the coke cans = Is that something to be concerned with? (Yes, I am afraid of the coke cans. I've never seen caps that size).

See the tuning string? It looks new to me, it's that way all the way down the string.
Notice no discoloration on inside of wood case, a good sign.

So as I said, first thing is cleaning then I can look for those other signs you mentioned Mark.
I have my work cut out for me.

One more nudie.

The caps are hard to check. Usually, if they don't look right, they are not. Look on the bottom of the caps and see if they have opened up and are leaking. Right between the binding posts.

If there are no leaks, here's how you can check them for capacitance. Remove the wires from them. With your meter attached, charge one of them up with a 9v battery. Hold the battery there for 10 sec or more. When you take the battery off, meter still connected, do they hold charge, ie. no more than .01 volt down in 5 sec or so? Then, multiply whatever voltage you have X .37, and note the result. Then. with meter still connected, discharge the cap through a 10K ohm resistor, counting the seconds for the cap to discharge to the computed 37% level. number of seconds X 100 = capacitance. If that takes too long, you can use a 1Kohm resistor and multiply seconds X 1000. This is very accurate, if you are careful and do your measurements accurately.

Usually if they are bad the capacitance will measure way down, 40-50% low. I've had a lot that were ok, but when they are bad, there is usually a visual indication also.