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It's Halloween - SX-1980 monster in my house! Thoughts welcome!

brainbanger

brainbanger

Member
Hi guys,
after endless searches and missed opportunities I was quick (and lucky) enough to score an SX-1980 on Ebay Classifieds. Called the seller five minutes after he posted the add, fixed a reasonable (but no bargain) price and agreed to pick it up on the other end of the country... 900 miles and 13 hours later the beast sits on my bench:

2016-10-29 10.21.48.jpg

The guy bought it new in 1979 and rarely used it for only three years until 1982. He moved house and kept the receiver unused in his home office ever since. It is in mint condition with only a mini-tiny dent on the frame above the meters. Cabinet, top cover and faceplate are dusty, but do not show signs of usage. The unit is a July 1978 HG-model with the rare FM de-emphasis switch on the backpanel. It has never been serviced, repaired or even opened!

A thorough check showed that everything performs as expected, even the quartz-lock of the tuner works like charm after all these years! Having read numerous threads about SX-1980 restorations / overhauls and given the fact that this receiver is a real investment I would love to have your opinions on which things need to be done (eg power supply) and which are more or less optional (filter caps?). I have fully rebuild two SX-1280s and recaped several other Pioneer receivers, but would not want to fully rip apart a working SX-1980 unnecessarily.

Excited greetings from Germany, :banana:
Andreas
 
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If its not broke then don't fix it, you know the old saying. that is one gorgeous receiver! you can just look at that and tell it sounds wonderful! great buy...........:music:
 
brainbanger said:
Hi guys,
after endless searches and missed opportunities I was quick (and lucky) enough to score an SX-1980 on Ebay Classifieds. Called the seller five minutes after he posted the add, fixed a reasonable (but no bargain) price and agreed to pick it up on the other end of the country... 900 miles and 13 hours later the beast sits on my bench:

View attachment 811819

The guy bought it new in 1979 and rarely used it for only three years until 1982. He moved house and kept the receiver unused in his home office ever since. It is in mint condition with only a mini-tiny dent on the frame above the meters. Cabinet, top cover and faceplate are dusty, but do not show signs of usage. The unit is a July 1978 HG-model with the rare FM de-emphasis switch on the backpanel. It has never been serviced, repaired or even opened!

A thorough check showed that everything performs as expected, even the quartz-lock of the tuner works like charm after all these years! Having read numerous threads about SX-1980 restorations / overhauls and given the fact that this receiver is a real investment I would love to have your opinions on which things need to be done (eg power supply) and which are more or less optional (filter caps?). I have fully rebuild two SX-1280s and recaped several other Pioneer receivers, but would not want to fully rip apart a working SX-1980 unnecessarily.

Excited greetings from Germany, :banana:
Andreas
Click to expand...
Hallöchen Bärliner,
I always check kleinanzeige, but I guess I missed this one. Just joking, I dont need another monster in my house. :)
Even though it is not broken yet, I think you should start reparing before using. Some old caps can short and create damage. Filter caps should be first one to go, even when they are not leaky. Then the other board, except tuner board. Offset and bias should be adjusted by pro when you are not confident.
It is a nice warhorse, they dont build it like this anymore.
 
mark warren said:
If its not broke then don't fix it, you know the old saying. that is one gorgeous receiver! you can just look at that and tell it sounds wonderful! great buy...........:music:
Click to expand...
So true!!! Just carefully listening to vinyl recordings that I thought I would know in every detail - WRONG! This machine produces a sound carpet of another dimension. I swear it feels like I am sitting in the middle of Madison Square Garden listening live to Clapton and Winwood :music: This receiver is a big step ahead from everything I listened to before. It beats a Yamaha AX-1050 in clarity and produces an even better punch than my SX-1010. I love my new favourite! :rockon:
 
What a smile you should have!
I'm thinking that a good tune up is needed.
Bare minimums:
Deox the controls.
Take care of the outputs by replacing the old paste.
Think about replacing the CS's N-Channel FET's, 2SK34's with EW's work-a-round.
Pioneer's Service Letter on the PS has you replace the 35v zeners for a 17 and an 18v in series.
Replace the old paste on the PS large regulator's
The PS is the life source and should be your focal point.
Not sure about the large filters, they do get old but they almost never see any rated use. (They are easy to replace)
Glückwünsche :thumbsup:
 
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zebulon1 said:
Glückwünsche :thumbsup:
Click to expand...
Thank's alot!
I will Deox and clean everything tomorrow and then start with the power supply. I do have 80% of the required parts on hand and will order the missing ones (for all boards and mods) from Mouser later today.

Today I do enjoy listening to the amazing sound. As said, Clapton, Winwood and JJ Cale are here tonight. Stevie Ray Vaughan, Jeff Beck and some other guitar gurus can't wait to please my ears, too. :rflmao:

I am in vintage HiFi heaven! :beerchug:
 
Holy monster Batman!!!!!!!!!!!! Nice find. Careful restoration with your experience should make that Godzilla stomp Tokyo. Enjoy the classic rock.
 
Congratulations !! A long "stalk" pays off!! (I see you also wasted NO time in updating your signature line!! lol...)

If it has truly set all these years unpowered, the boards will not be baked to death, e-caps also will be in better shape than usual.

Still, air pollution will extract it's toll upon the switches and pots.

I would just "death proof" the power supply for now. INCLUDING getting the two hot power pass (80v) transistors off the board and over on the big heat sinks.
 
Thank you all for the kudos and hints.

I have opened the 'Holy Grail' and taken lots of pictures. This set must have truly been used very seldom. The PS board has only very minor burn marks:

P1100964.JPG

I will work my way to the back of the board and decide after a thorough inspection if I recap/mod the original board or probably go with txturbo's re-design?

Definitely more attention is required for the power amp boards:

P1100956.JPG

While taking them out for cleaning I will recap and renew the thermal paste. And yes, Mark's 'number 2 pencil trick' will be used at the connectors. :biggrin:

So: challenge accepted! This beauty will get some wellness treatment and a moderate facelift to become a true diva! ;)

Andreas
 
That's a MONSTER receiver!!

Have fun plumbing newer things under that hood and the peace of mind you'll have when you finally sea trial her and truly open it up.
I stumbled across an SX-950 in the local paper back in June that was original owner, receipt, stories and all, and been in storage 25 years.
I took it easy on her all Summer with bookshelfs and Dynacos and sounded wonderful, until....... it met the Infinities and vinyl together one fateful day.
Though seemingly not driven hard and fanned, she went out with a little puff of smoke.
Local guy bench'd it, but said he just didnt want to do it (he does old tube stuff now mostly) and that it burned a few transistors and some caps on the phono board which is connected somehow to the power supply board he showed me (original fold-out schematic) but all the 8 output transistors and preamp side was all good.
Just replace everything you can while in there is my motto now....... everything.....except the important vintage-sound stuff that probably NEVER burns up..

A Winter project for me and certainly I too will be searching the archives here for whatever "Bulletproof / Infinityproof" buildup-buildout to for something I only heard for a few months but became totally worth fixing right and keeping another 30 years or at least passing it on in working condition.P1080101.jpg

The lesson I learned is that it's true what's said about those electronics stored all those years if even in great storage conditions.
They try, but somethings GONNA break eventually when it's at the 12 o'clock position.
A 50 cent part takes the whole operation down and it's time for open heart surgery.
Great thing is that they're substantial, solidly built and worth maintaining.
Though I'm no master solderer, it sure makes it nice when the enginers layed things out for repair access that doesn't involve doing heart surgery through the patients back!
 
Congrats, Andreas, glad to hear you found what you were looking for. I scored a QX-9900 of late, it is a nice looking unit. Something to play with this winter.
Nice to hear the the jfet phono eq amp is a step above the rest of the class.
So as a test, if you do not mind, if you connect the 1980 phono stage, using the 1980 tape rec output, to your other amps inputs (aux or tape mon play-in) do you notice the improvement of the phono stage as well? I assume you tried varing the cartridge load C, did you notice the tonal quality change?
Zeb and MTF offer good suggestions to make it more reliable.

Enjoy
JJ Cale Crazy Mama
 
Congrats!!

Love the Pioneer monsters. Again Congrats, that's quite a find, and would love to be part of the club one day. :)
 
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