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View Full Version : Resurrecting an oldie



Donald
12-15-2013, 09:01 AM
In 1976 I bought this beast. Pioneer SX-1050. Don't know what it weighed then but now it is 50 lbs. :) It was used with my JBL Dorian S12 speakers which I bought in the late 60s and still have. Apparently it sold for around $700 then. Which was almost a months take home pay for me. Now they are on eBay for $260 and up.

What I love about the Pioneer was the feature set. 3 sets of speakers, main IN-OUT jumpers, 4 band EQ, tape loop, 120 watts, etc.

http://www.classicaudio.com/forsale/pio/SX1050.html

It has not been used for 10+ years. I bought a Variable Voltage Regulator just to fire this thing up.

How should I fire this up and what should I look, listen, smell for as I move up to 120 volts?

6088960890

BMWCCA
12-15-2013, 12:31 PM
Granted, I know nothing about this subject but somehow I feel I remember hearing a Variac is not just unnecessary on a solid-state device but may even cause some harm? :dont-know:

SEAWOLF97
12-15-2013, 12:56 PM
Granted, I know nothing about this subject but somehow I feel I remember hearing a Variac is not just unnecessary on a solid-state device but may even cause some harm? :dont-know:

I'm with Phil on that one.

Just had an SX-1010 , plugged it into the wall , no hum, smoke or noise, so put in headphones to check it out. All seemed fine, so tried cheap speakers. fine again.

So then better speakers. All good. Those old Pioneers are really built well , I personally would not hesitate to "give it 120 & see what happens"

Mr. Widget
12-15-2013, 01:56 PM
Those old Pioneers are really built well, I personally would not hesitate to "give it 120 & see what happens"
:yes:

I also agree with Seawolf on using robust or disposable speakers.


Widget

Donald
12-15-2013, 03:04 PM
All my speakers are JBL. None of them are disposable. :)


:yes:

I also agree with Seawolf on using robust or disposable speakers.


Widget

Donald
12-15-2013, 03:18 PM
Well, I guess I will just fire it up with nothing attached and hope for no smoke or flames. :banghead:


I'm with Phil on that one.

Just had an SX-1010 , plugged it into the wall , no hum, smoke or noise, so put in headphones to check it out. All seemed fine, so tried cheap speakers. fine again.

So then better speakers. All good. Those old Pioneers are really built well , I personally would not hesitate to "give it 120 & see what happens"

1audiohack
12-15-2013, 03:47 PM
If you don't find an answer here that makes you comfortable, take it to a trusted repair shop and pay them to wake it up for you.

Barry.

Earl K
12-15-2013, 03:57 PM
FWIW, my trusty Sherwood S-7200 receiver that I bought new in 1973 ,( as well as a duplicate for my parents ) both still have good power supply caps .

Still, I guess one can't be too careful if you truly love the gear .

If you bought a Variac, I would use it to ( possibly ) reform the electrolytics ( power caps ) as directed all over the internet ( do I need to the googling ? ) .

http://orgchem.colorado.edu/Technique/Equipment/Images/Variac.jpg (http://orgchem.colorado.edu/Technique/Equipment/Communityequip/Variac.html)

:)

Donald
12-15-2013, 04:52 PM
Well, the variac method seems to involve getting the caps out of the unit and creating a DC current limited circuit then building up the voltage to the caps working voltage.

i thought the process was to just slowly ramp up the AC voltage to the whole unit.


FWIW, my trusty Sherwood S-7200 receiver that I bought new in 1973 ,( as well as a duplicate for my parents ) both still have good power supply caps .

Still, I guess one can't be too careful if you truly love the gear .

If you bought a Variac, I would use it to ( possibly ) reform the electrolytics ( power caps ) as directed all over the internet ( do I need to the googling ? ) .

http://orgchem.colorado.edu/Technique/Equipment/Images/Variac.jpg (http://orgchem.colorado.edu/Technique/Equipment/Communityequip/Variac.html)

:)

jbl
12-15-2013, 05:32 PM
You won't hurt anything using a Variac. The Varac is used to bring the voltage/current up slowly on gear with a known problem. Bringing up your Pioneer slowly will only result in the relay engaging at a certain voltage point as you advance the voltage dial. Under normal conditions, the circuit would stabilize before the relay engages. Of course if there is a problem with the amp it would stay in protection, (Relay not engaged) where as it would engage a few seconds after firing up at the AC outlet voltage of your location if everything is ok.

BMWCCA
12-15-2013, 06:18 PM
Just saying that my Crown owner's manuals all caution against running any equipment outside a window of 10% variance from rated power requirement. I suppose if you're just turning it on and not using it, it might be okay. I have no idea.

More thoughts here: http://www.audioheritage.org/vbulletin/showthread.php?4256-Varic-on-solid-state

SEAWOLF97
12-15-2013, 06:27 PM
Maybe Phil I are just recalling this old post ?


Also, some SS amps with brick-wall power supply regulation can have their voltage regulators damaged by too little input voltage. Unless you're SURE that you DON'T have regulators or switch mode components, I'd be careful about running a SS amp at lower-than-spec voltage for more than a few moments...

Regards,
Gordon.

Mr. Widget
12-15-2013, 06:55 PM
You won't hurt anything using a Variac.I damaged the power supply of a preamp doing this... I won't be using a variac to bring up any equipment in the future.


Widget

mech986
12-16-2013, 01:11 AM
May be wise though to build a Dim Bulb tester that will limit inrush current - if something has or will fail shorted, could save extreme damage and give some protection while everything is starting up and stabilizing. A lot of AK techs use that to bring an old unit up for troubleshooting. And with a unit sitting idle for that long, you don't want to chance turning it into an expensive door stop.

Donald
12-16-2013, 04:32 AM
Is there not a voltage across the bulb thereby reducing what is available to the unit being tested? I understand the variac may not limit current.

I hope everyone has a stash of incadescent bulbs. http://money.cnn.com/2013/12/13/news/economy/light-bulb-ban/

I did see an article that used a 3-way bulb. May stock up on them. :)

Earl K
12-16-2013, 04:57 AM
I damaged the power supply of a preamp doing this... I won't be using a variac to bring up any equipment in the future.


Widget

Thanks for that !

Good to know the procedure isn't accepted on a fully ubiquitous level .

FYI, I searched ( Variac ) briefly over at AudioKarma & DIY ( solidstate ) and from my quick perusals it seems that a Variac is typically used "hand-in-glove" with the ( current limiting ) light-bulb .

Some manufacturers ( such as Adcom ) specifically mention ( in their service manuals ) not to Variac .

:)

jbl
12-16-2013, 02:55 PM
I damaged the power supply of a preamp doing this... I won't be using a variac to bring up any equipment in the future.


Widget

What was damaged? Why did you try it with a Variac? What was the original problem?

Mr. Widget
12-16-2013, 08:33 PM
What was damaged? Why did you try it with a Variac? What was the original problem?Not sure if there was a problem, the preamp hadn't been powered up for several years.

As I brought up the power, a rectifier tube blew and I sent the preamp to a tech to repair it.


Widget

Donald
12-18-2013, 04:34 PM
Saw one mentioned in my searches regarding old caps. One was on eBay and I won it. May have to fix it before I use it. :)

http://www.ebay.com/itm/281225554799

Lee in Montreal
12-20-2013, 02:42 PM
I think the only prep I would do before turning the on/0ff switch would be to pop the cover and vacuum as much dust and "angel hair" as possible. Then turn the amp on with the cover off and check for smoke ;-) Using cheap drivers would be wise. Even $5 car speakers will do.

Donald
12-27-2013, 07:04 PM
It arrived. I checked the circuit side. While the rectifier had not come apart like one blogger's did mine did have a detached lead. Both wires the rectifier were attached with were over an inch long and not insulated. I added some shrink tubing on the leads. Saturday I will clear some bench space and fire up the oldie using this oldie. :)


Saw one mentioned in my searches regarding old caps. One was on eBay and I won it. May have to fix it before I use it. :)

http://www.ebay.com/itm/281225554799

Mike Caldwell
01-06-2014, 11:05 AM
I would plug it in and turn it on, having said that I would not have it connected to any "good speakers". For amp function testing I have some old junker garage sale speakers as well as a moderately high power dummy load. Sometimes I will not even hook up the junk speaker for the initial power up, I'll first measure the speaker outputs with a meter to see see if there is any deadly DC voltage present and then just quickly touch the test speaker leads to the outputs before making the final connection.

Some electrolytic cap replacement may be in order.

I just did a complete electrolytic re-capped my 80's era Hafler pre amp and it took care of the slight hum I was starting to notice and the mid range graininess I had noticed appearing in the left channel.

Donald
01-08-2014, 03:21 PM
Well, set up my new\old electric tester and fired up the Pioneer. No smoke. Neither unit. :) Measured DC at each of the speaker terminals. Highest was .014 volts. Tuned in an FM station and was getting AC on speaker output A. Have not tried an actual speaker yet. All the toggle switches work fine except the power on. A first I thought it was broken but it turns out the lube has just gone beyond molasses. Will open it up to clean all the pots and switches and lube the tuning system. I feel the 70s coming on. :applaud:

Eaulive
01-09-2014, 11:25 AM
May be wise though to build a Dim Bulb tester that will limit inrush current - if something has or will fail shorted, could save extreme damage and give some protection while everything is starting up and stabilizing. A lot of AK techs use that to bring an old unit up for troubleshooting. And with a unit sitting idle for that long, you don't want to chance turning it into an expensive door stop.

I agree, use a 100W incandescent bulb in series, the purpose is to limit the current in case of a component failure, not to decrease the voltage in a working unit.

I use a 100W bulb on big domestic amps like this, a 60W bulb on smaller (25-35W) units and a big 500W PAR64 bulb for kilowatt commercial amps.