Pioneer SX-434 Vintage Receiver Restoration 

Those metal knobs in old receivers have such satisfying weight, unlike the cheap plastic knobs on today's models.

Got my first hifi system in 1974. It consisted of this Pioneer SX-434 receiver, BIC-920 turntable and KLH model 31 speakers all for less than $250. A few years ago at work they were throwing out this receiver. I took it to my fixit guy and for $60 he restored it. Now the Pioneer SX-434 sits in my kitchen and powers a Nakamichi BX-1 cassette deck and Boston Acoustics A-40 speakers. A very happy ending.

My Dad had this exact receiver, it was a pretty good unit, I grew up with this machine!

very nice! i don't know my way around servicing vintage Hi-Fi besides changing caps and check for right voltages, but i like watching stuff getting repaired.

Thank you very much for the walkthrough. Just got finished recapping my SX-434. Wouldn't have been able to do it without you. Great tip on cleaning the potentiometers. My balance was always a little crunchy but its perfect now. No need to replace it.

Thanks for the good video.Regarding changing 6 bulbs on the radio.

What a really beautiful receiver! Great job!

I enjoyed watching this. Thanks for sharing with us. I wish I had the knowledge on how to do it.

When you're replacing a single cap with two that don't exactly match the original, it's good practice to write on the board what that should have been (like .47uF), for future reference :)

Great Video! Thank You for the detailed information and innovations! THIS WAS VERY HELPFUL!

Very informative and fun to watch!

Excellent work Jan. I enjoy this type of content very much.

Loving the retro repair really built to last these amps not like the throw away hifi of today with custom ic etc which cost the earth if you can get hold of them to replace. Great Job looking forward to other repairs.

This is great. About to search for the Marantz rebuild. I just acquired a 2240 that needs love.

had one of these when I was a kid. hooked my NES up to it and an old composite color monitor. later a betmax for some TV. fun times

13:40 I got the successor of the desoldering station, the ZD-985, but it's basically the same. It's the BEST TOOL EVER - so much better than solder sucker & wick. Thanks for the recommendation!

Amazing video like always. Thanks a lot.

My vintage stereo project (were I going to attempt it) would be a couple of 8-track decks. One is a full player plus radio receiver (belt good, no playback) for a friend, and the other is my own 8-track *recorder* that I finally found where I had stashed it away (same problem, belt is good, no playback).I just don't have a good soldering setup (irons *or* place to do it)

Loving the LED mod !

The power transformer is wound normally. The copper wrap, that lies over the windings, is to act as a shorted turn outside of the core of the transformer, which reduces the effect of any magnetic field from the transformer, that would induce hum into the nearby electronics.

Nicely done Sir, 10/10 would watch again \m/ :)

My first serious audio equipment was a Pioneer SX626 that I received as a gift in 1971. It was a nice little unit, a lot like this. By the mid-80’s, the sound was getting weary so I donated it. Hopefully someone knew how to service it and got more enjoyment from it. If it is still around, I have seen people asking $350-$400 for one.

Great video Jan. I didn't know you're also into vintage audio receivers. I enjoy your Commodore 64 videos but seeing this is also very cool. I'll check out your Marantz and Sansui resto videos. Danke!

Bravo extra !

I like the part where you convert the bulbs to LED's. Wish you spent a few minutes going over why you added the capacitor between the rectifier.

I would replace small caps (1uF and less) with film capacitors. You can get them in small sizes and they last forever.

One thing you should have done is adding thermal paste between the mica and the heat sink, and between the mica and the transistor. Rest of the work was really good 👍👍

i replaced the light bulb on my saba RS 910 with a LED as well (because i had 2 bulbs die in under 3 months already) - good thing the saba has DC for the bulb so all i did was add a resistor before the LED and some mechanical modifications (LED diameter was larger than the bulb so i had to make the hole bigger)

All we see is Jan BETA Jan BETA, when are we going to see the Jan STABLE version 1.0?

Excellent project. Can I ask where you got the very small wire stripper you used for the bulbs?

Great video. I have the same one, the right channel has 24mv and the left 0mv and it sounds distorted, how can I adjust the bias so that it sounds good

@Jan Beta... just a tip..... as you see at minute 39:01 ... the numbers 94.. 104 and 108 of the dial... are illuminated with a much clear tone of blue.... because it hits directly the brightness of the LEDs on those numbers ..... I got better result in my amplifier.. pointing the LEDs to the back.... pointing to the silver plate behind.... so the numbers get illuminate with the light that bounces on that silver plate more smoothly...

Great video, one question pls. Where i can buy that sanyo a5870 transistors?

The transformer isnt "flat wound" but the copper strap you see around it is quite common on EI transformers used to power audio circuitry. It is simply a screening band to keep emissions down. The main bugger with these amps (and many Pioneer made) is that they use an odd "multiple diode" device as part of the bias current feedback. If the output transistors fail, these diode strings frequently get toasted, and it is impossible to get them... so you either have to make a hack with several 1N4148/zener diodes, or create a VBE multiplier using a BD139 or something like it. It's a nice little receiver you've got here though.. i'll carry on watching now (I got 5 minutes in before commenting ;))

I have one and the nob to turn it on is super stiff how do I make it not super stiff. And this one of mine has the original capacitors and they work fine every thing works on it. And the balance nob and volume make a scratching nose. How do I clean them because it sat in a room where I put my hand on the top and the dust made my hand go brown.

Great video! I used this to change the lamps on my Pioneer SX-434 and worked great. Still the sound is failing from time to time (specially after 5/10 minutes of usage )either on left or right channel. I ear a sound like an explosion really loud or just fades and becomes intermittent... I already cleaned it and used the Teslanol contact spray Could it be the capacitors? Any ideas? Thank you!

New subscriber. Love your videos. I have a sx-650 pioneer. Changed the display bulbs to led was fine for about six months now they flash. Help.

I always replace incandescent lightbulbs with regular automotive LED’s and never had a problem. With out the rectification circuit. Can you explain. Please

Would you mind telling me roughly how much a restoration like that would cost, I just bought a Pioneer sx-770, would like to get it restored.

What termination style does the filter caps have?

Hi, I bought one of this a week ago, exactly same model, it was working fine only minus was only half of the front radio quadrant was lighted, and the bass knob was making a static noise but just when increasing and decreasing the bass. I removed the knob and sprayed some electrical contact cleaner inside of it, and the result was lost of bass and and almost all the sound, now only little sound is coming out from all outputs. what can I do? please give me some advice, I will really appreciate it. ☺

Nice video. Thank you. I have the same receiver, bought used last week. It's in almost mint conditions. When I listen to the radio and the station is in stereo the red light appears and shows "stereo". However, if I push the button "mono" on the receiver, the light does not change. The sound does change but not the indicator light. Is that normal for this receiver? (With my Realistic gear, when I do that the stereo indicator light goes off.)

Hallo. Ich habe einen Pioneer SX-636 und möchte auch gerne die Kondensatoren tauschen. Habe leider noch nicht ganz so viel Erfahrung damit. Gibt es zusätzliche Tipps, wo welche Kondensatoren geändert werden müssen / sollten? In einschlägigen Foren wird ja oft davon abgeraten, wenn das System an sich funktioniert. Und wo bekomme ich das Material her? Wurden jetzt Kondensatoren mit höhrerer Temperatur- und Spannungsfestigkeit verbaut? Und: alles Elkos oder auch Papierkondensatoren o.Ä.? Wie ist das mit den großen Netzfiltern? Bin etwas besorgt, dass die irgendwann mal hochgehen und ich an einem Herzinfarkt sterbe. :'D Und wie sieht es aus mit den Transistoren? Auch tauschen oder lassen? Desweiteren bin ich besorgt um den Trafo. Dieser ist auf 220V~ ausgelegt und kann bei meinem Modell auch nicht verstellt werden. Kann ich mein Gerät trotzdem gefahrlos verwenden, obwohl die Netzspannung heutzutage höher ist? Ich weiß, viele Fragen. Aber ich freue mich trotzdem auf eine (kurze) Antwort. Bin durch meinen Pioneer auf dieses Video gestoßen und schaue mir gerne noch andere Videos auf dem Kanal an. :)

I have a similar one but one channel has a scratchy sound output. Shop says not worth repairing. Can you help?

10:51 can you believe the construction of that audio unit........ I mean.. have more solid metal than many modern cars... :-D @ramdileo take a look to this one.. ..

Hi from Spain. Do you know how to say in English to the welding or joining of spiral cables? And what tool is it made with? Thanks and best regards.

Master, how many volts for 6 lamps for the radio?

I had the same, but now there's a lot of humming on the AUX and TAPE IN inputs. Do you know what might be wrong and how to fix it?

I am looking for the best place to buy the cord that is used for the tunning of a SX727 I live in Qld Aust

where fm and am antenas must be conected?

Bom dia amigo ,tenho um sx424 como é possível adquirir 2 botões de ajuste porque aqui não encontro..obrigado

The Pioneer SX-434 was made from 1974 to 1976 - Yeah I cheated and Googled it.

Jan I was wondering don't the amplification FETs not need replacing after 40 years of hard labour ?

i think your yellow led is so dim, because you actually forgot you rectified your nine volts down to five volts, so you need a ~150 ohms resistor instead.

Here is a link to the Service Manual. It is a free site, but you must register before downloading. www.hifiengine.com/hfe_downloads/index.php?pioneer/pioneer_sx-434_service.pdf

is there not a worry that the replacement caps wont last anywhere near as long? after all they are working, they may work another 40 years! many old caps are larger as they dont rely so much on the electrolyte, and it boils out less anyway, there in fact used to be dry caps which seem to last forever, but too large to fit in modern devices

I have a funny feeling that it was probably possible to unscrew the heat sink from the frame and leave the transistors attached.

I guess these ,47µF caps are not THAT exotic... From somewhere I got a whole bunch (100+) of them, never used them and found them always being in the way in my parts bin - i would donate them if you gave me any contact data via PM ;-) (just contacted you on Twitter)

Wieder ein tolles Video. Für 99% ist so ein Receiver Schrott und wird irgendwann weggeworfen. Manchmal überlege ich solch einen Stereoreceiver mit zwei alten Boxen für meinen Computer zu verwenden, da man heutzutage keine vernünftigen Boxen mit ausgeglichenen Klang (Hoch/Mittel/Tief) zubekommen scheint. Aber da bekomme ich wohl Probleme mit der Abschirmung von Receiver und Boxen...

Since I've been watching a lot of Mr Carlson's Lab (ru-vid.com) I'm a little disappointed you didn't recap and retune the radio.

" these things were made to be serviced"....... NOT !!!!!...... anything put together can come apart....that does not mean you should....unless you know what the heck you're doing....which this guy does....but again you can always say you did all of this so you can B.S. yourself through some " audiophile " chat room...