I love the current presentation the way you present it, even a season tech like myself, needs a brush up on new approaches.

Buenas estimado justo lo que comenta en el minuto

The problem with my SX- 939 is that after about 5 min or so it shuts off the sound. I've hooked up new type Plokauido speakers to it instead of my JBL 4311X speakers which I thought

Is there a list of old transistors to new ?

Tony another great Video, I have some SX- and they get really hot, How hot did it get after installing the new MJE3055T and MJE2955T ???? after 45 years, can these boards handle that much more heat before breaking or melting?

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I am in the process of restoring the same receiver sx-939 and have many of the same issues you have where someone had gotten into the unit and did a poor job. Also soldered the fuses in. I cleaned everything up and used Deoxit on all of the switches, now they work great. One of the things I would have loved to see is how you removed the boards. How did you unwind and rewind wires? How did you keep track of where everything goes so you know how to put it back in? I did not remove most of the wires and just loosened them from the tie downs and flipped the boards over or on their side to work on them but it was a pain in the ass and soldering was very difficult. I have recapped everything and replaced most of the known bad transistors but not all. I am currently at a stand still. I checked all of the power transistors and they are good. It lights up and everything appears to work fine with the exception of two blown bulbs in the display which I am going to replace. After I had done all of the work the receiver still does not work. On power up it does not make any sound out of the speakers. I am new to this as I took it up for a hobby in my retirement and have been working at it for about a year and a half but never took on a job like this, just simple things like fixing speakers, appliances, small radios and the like. I could use4 some help if you have the time.

Tony my favorite sounding pioneer receivers. Is the 30 series I think you said it’s yours as well what makes them sound better then other pioneer receivers just curious thanks

Tony is truly the ‘Bob Ross’ of restoration and repair - and I mean this in the absolute sincerest and best possible way. Like B. Ross (who makes his incredible paintings seem easy as he’s doing them) Tony makes these difficult and intricate repairs look relatively easy as well. Always patient, meticulously thorough and of course a shear pleasure to watch. Thanks Tony for these!

I just watched this video. you have a lot of useful information in here. I purchased my SX-939 when I was in the Army in Germany in 1974. It has the changeable plug for the AC input power. This receiver is fantastic. I love the sound. I have a set of JBL 4311 Control Monitors that I also purchased in Germany. Everythinf is working and sounding great. From time to time the protection relay will click out and then back in. From your video it sounds like it could be anyone of a couple of things. Right now it is not a big problem. When I turn up the volume to a nice listening level. (the little arrow on the volume knob points to 7 o'clock when the sound is all the way down. I turn it up to just about the 9 o'clock position) The protection relay will click out and then right back in. Sometimes I feel like a cap or transistor is a little leaky. What city are you located in or near? There is no way I will do anything more that clean the dust out it. After what you said at the beginning of the video. I'm taking your advice and leaving any kind of repairs to a professional like you. If I begin to have larger issues with this receiver I will contact you.

What would that cost em ? What city and state are you in ?

Hi xraytonyb, I'm taking your warning to heart about the Pioneer SX-939 is not for the beginner. I'm a beginner and would like to try to rehab a vintage receiver. Do you have a recommendation of a vintage Pioneer model to start on? Marantz? Sansui etc. Love your clear and well done videos. Thx Ed

GREAT pair of Video's, Tony! Sooo applicable to me as I still have my original owner SX1010, which I purchased in 1974, extra parts and Pioneer service manual books, brochures and 1978 Hi Fi mag review. This is from while I worked during HS and College holidays/vacations at Alltronics and later Acrosound Electronics in Flanders NJ, performing Authorized service for Pioneer, Sansui, and Revox. I had saved up all summer working there, getting the great price of $470 Employee Discounted cost (Fair Trade price was $699.95!!!). I later recapped the giant 18,000uF filter caps there under warranty, somehow they leaked a bit. I used to have a big FM Yagi on the TV tower atop my parent's house, with my Ham dipole antennas out to some trees. You could set the perfectly calibrated FM dial pointer at ANY FM channel, and hear 1-3 stations from Boston to Delaware pop in and out with the 1dB Capture Ratio as I rotated the antenna. I had this 120W/4 ohms/channel Receiver at college in IL, where I bought 2 OHM F Walsh Driver speakers for $900 thru the BU ARC Radio Club president's distributor business, in my Dorm room!

Are you using a different mike? Your voice is muffled...no highs.

I just got one of these amps passed down from my grandpa. I’m planning to do a restoration, and, while I’ve worked with other vintage electronics before, I’ve never worked with vintage audio. this project looked somewhat intimidating. Your video here is IMMENSELY helpful, thank you so much for sharing your personal experience and tips for parts like the relay.

I have one of these beasts that was given to me and needs restoring. One channel is intermittent so it looks like I have a bit of work ahead of me. Hopefully I can get all of the parts through DigiKey. Thanks for the video.

Love it when you are splitting hairs :)

Relays are (generally) not able to open a dc fault higher than about 30VDC...you get an arc instead. Isn’t it better to instead use two back to back low RdsOn FETs, which can interrupt high voltages and do it faster and less expensively?

how do you remove the wires? and do you mark them whilst removing? each board apparently has around 20 wires.

I have a sx 838 that has no sound,I'm thinking it's that protection circuit because I do not hear the click after turning it on. Last time I used it was like 10 years ago,everything worked when it was shut off !