PIoneer SX 450 Repair and Restore

This SX-450 was a bit rough when it arrived on the bench. After replacing the capacitors, and two transistors, It began to work pretty well. All of the switches and pots got cleaned and then we replaced the incandescent bulbs with LED's. The tuner really came to life after a proper alignment! I was amazed how good this little 15 watt per channel receiver sounds. I can now say that all of the '50 series receivers sound similar. The only difference is power and volume, but this "baby SX" really holds it's own!

[@rrangana11]

I spent my 1.5 hours of my life on watching your Great work on troubleshooting a great piece of vintage electronics. Nice work xraytonyb!!! I am on youtube since 2007, but I don't know how I missed your videos. In the coming days I am going to binge-watch your videos.

[@Royalbigness]

I wished I learned this trade when I was young. Starting out in my mid 40s is a little more challenging. But, I am a willing student. Thanks again for the time you take to make these videos. You and the others out there are providing an invaluable service to all us noobs. Thank you Sir !

[@ovi_4]

Nice instructional video. By the way, I have found a way to spray those hard to reach pots without desoldering them. You make yourself an S shaped plastic pipe and that will fit t right underneath the pots and do it tat way. Is really no need to dismantle all that metal work and desolder all pots just to have them cleaned. It'll save you a substantial amount of (otherwise) wasted hours on each restoration. However it will take some practice to bend the plastic tubing to the required shape. It took me about 7 tries until I came up with the right shape and now it works like a charm no problem whatsoever.

[@nycitalianess7825]

Audio Surgeon!! Your intelligence and abilities FAR EXCEEDE most of Today's "so-called" Doctors. SALUTE YOU!! Fabulous! Great to watch you work, and learn from you, at the same time! When I was about 8 years old, just for fun, I wanted to pretend that I was a "Surgeon" or an Electrician or a Mechanic, so I took apart my Brother's brand new 1966 Sony Transistor Radio (which was covered in a gorgeous removable black "real leather" casing!) Incredibly, I was able to put it right back together just as it should be. My Brother thought; "Wow, Impressive Kiddo!!"... but what he STILL doesn't know to this day (unless he's reading this KZbin comment) is that it was, actually, the FEAR of what he might do to me, that made me put it back together so efficiently! FEAR TRULY IS A MOTIVATOR ;) Great vid on an amazing vintage alltime Pioneer favorite!! Thank you!

[@hugeelen]

nice comment! tx

[@defaultname4397]

Tony....I have made my living for over 37 years working on stereo and guitar amps.you would think I would enough of it at my shop....found you by accident last week...I find your videos very entertaining....great work keep it up Charlie Harris

[@Craig_Spurlock]

I still have my father's SX-450 and it all still works, except for the radio strength dial and the lights are dead except for the stereo indicator. It is time to do a restoration. I am happy to have found your video!

[@mdzacharias]

I clean those push-button switches all the time just spraying D5 using the little tube down the side of the push-button shaft where it goes into the body of the switch while holding the receiver at an appropriate angle to use gravity to help get the cleaner to the contacts, then of course work the switch vigorously. (Front panel has to come off first.) Works every time except when there is corrosion inside the switch, at which time of course the switch must be dis-assembled and the locking pawl, spring, etc removed, and the switch shaft pulled out from the front (ugh - easy to lose parts). In the business for 35+ years - just retired. In my experience the channel imbalance is more likely caused by the volume control and/or vol control tracking issues. Merely adjust the balance slightly; that 's what it's there for. In testing, adjust the balance for equal clipping also. :-)

[@guachito33]

i didn’t understand 98% of the terms he used , but i still watched it

[@Nuno.A]

Just started seeing your videos, bought a Pioneer SX636 and I am researching whatever I can before I start working on it, really like your videos, good work

[@syedmahdi8947]

Sir, I have a CARVER M500 dead power supply problem, I checked the DV 74& DC 40rails r low pl advise me how to check the power supply.

[@hugeelen]

It must be a very satisfying job to be able to repair it! Greetings from Belgium!

[@patrickoconnell3896]

I picked up a SX-450 that had the power cord cut off and the glass was broken. I tossed it on the shelf never thinking much of it. I think now I will look into it to see if it can be saved. Nice video.

[@xraytonyb]

Don't hesitate to put some time into it to fix it up. You won't regret it!

[@ralph7585]

The SX-450 is a fantastic elegant looking little receiver. I have two of them, fully restored 5 years ago and one of them plays every day, in the weekend the whole day. No problems, very sweet sounding great receivers! They have low outputs, but the 15 Watts are real and strong! In comparrison with the SX-850 I also have for serious listening they sound just the same. Thanks for the great upload!

[@xraytonyb]

I agree. Awesome receiver! I really like all of the SX - '50 series receivers. Great design and build quality.

[@brig.4398]

Good job, this video was a bit long but you carefully explained everything you were doing. Thx for uploading this.

[@xraytonyb]

Thanks for the comment! I'm still getting a feel for how much I should put into these videos. This one was definitely a bit long. Thanks for watching!

[@InquisiitorWH44K]

Tony, bought one of these new with a PL-514 turntable way back when I was in high school. Lasted me many years with no problems. Eventually, stopped using it and gave it away, but kept the turntable. Wish I'd never gotten rid of it. But just picked up another one. Looking to go through it first before turning it on. Thanks!

[@danielross868]

Hi Tony. I realise this is an old video, but thought to add my experience with the SX450 for Bias adjust and DC Offset for others who may visit this. I had to replace some outputs - originals were SD313- used MJE15032G (same pinouts). Had to replace some driver transistors (Q207/Q208 2SC1318A with KSC2383Y) same pinouts and (Q209/Q210 2SA720) with KSA1013Y same pinouts. Now for BIAS adjust, I replaced the 82R resistors ( R221 and R222) with 100R multiturn posts (middle leg soldered to one of outer). I could adjust bias down to approx 20mV. Scope sine test , just prior clip, achieves approx 12.88Vac RMS into 8ohm load = approx 21W one channel. Nice clean sine... For the DC offset, I took the advice of service manual and connected 8ohm load. One channel had circa 30mV, the other, a rather large 300mV. I replaced the 2SA725 transistor sets Q201/203 and Q201/204 with carefully matched Vbe / Hfe type KSA992. NOTE: Watch the pinouts of replacements. Thank goodness the screen printing on component side of PCB indicates correct orientation. I now have circa -18mV both right and left, so good success. Thanks for the video. Now I have to get onto the tuner, like yours mine seems dead... Keep up the videos. Your knowledge is vast and your presentation and "simplification" is invaluable...cheers from Sydney, Australia.

[@marvieachanzar4674]

Essential to our hobby and passion - Thank you for what you are doing !!!

[@Royalbigness]

When I have to clean out a very dusty unit, I use pressurised Dry Nitrogen from a D sized cylinder. I am a commercial Air Conditioning Tech and have these cylinders at my disposal. So outside I go with a nice medium sized paint brush and the Nitro, i blow the crap right out. Then I spray some electrical cleaner and repeat the process until it's nice.

[@doxierottenbreath5773]

This is great stuff for those that are into this stuff, and I am into it - thanks Tony...

[@jasonthejawman5442]

Tony appreciate You, Learn so much you expalne it so well, Thank You.

[@KevinCoop1]

I have a Technics from 1977 that pretty much looks like that Pioneer. Found out it was made by Pioneer. Still works great and sound! I run it at 3 on 5he volume knob. Pretty loud there.

[@danbasta3677]

Technics stereo receivers and component systems as I know it, is a subsidiary of Panasonic Electronics. It couldn't have been made by Pioneer Electronics, two different companies, Pioneer and Panasonic. Panasonic electronics inc. Has recently bought out Sanyo Electronics as all my tv sets are Sanyo wide screen tv sets and and I love them very much. They all have been very reliable and work perfectly all the time.

[@bobmulhiemer7564]

Tony ! I loved this video so much ! Thank You

[@RegiPavan]

Excellent video, learned a lot here... Thanks and please keep bringing then up! Take care.

[@robinfereday6562]

I so admire people with this kind of knowledge and such a fascinating video even if I didn’t understand any of it😉😉😳

[@qprhooligan]

First thing you should do before starting this is clean all the pots and switches. Wow.

[@kennynvake4hve584]

Is it possible to use your pin drill and drill a small hole thru the circuit board at the point where you would spray your cleaner into the pot....thus not having to remove the pot at all...to clean it, and save all the time doing it. I know this is thinking outside the box but that is the way I am.

[@johnschroeder9910]

Had the sx450 back in 70 s80s.

[@f.k.burnham8491]

Always check "new" parts before installing. I would have used my signal tracer to follow the signal right after testing the PS. Much quicker, IMHO, (but then again I have only 5+ decades in the field). I use an old el cheapo soldering iron with a thinned down tip to melt a tiny hole in the back corner of the switches. Just barely melt thru, spray cleaner & lube in then cover hole with a dab of RTV. I modified a spray tube to get into the pots from the bottom. Saves mass time & hassle. The brown glue should all be removed. They even used that crap on the bottom of some of the caps to hold them in place. It WILL turn conductive after many years. Good trick on using the LED's!

[@ronjarosch8287]

Because the power knob is also the speaker selector, I would've checked for sound out of the headphones right after the cleaning. My SX-450 has connection problems in that switch. It always turns on, but the connection to the speakers is iffy.

[@TheGregWallace]

Looks like you have enough high tech tools to build a rocket ship..LOL!

[@stevegreenwood7837]

Hi Tony great vid interesting too, you sure know your stuff. nice one thanks

[@tommygreist9560]

Great video.It was very educational for me.

[@csleeut]

I bought an SX 680 where the tuner does not work. Probing the supply to the tuner board, I see not 13.6V. Then I started probing the transistor supplying that 13.6V. After a few probes around the transistor, it started working. It's been working since. I suspect a capacitor near it is bad as I see some black crud near the base. Does anyone ever experience such a phenomenon that fixes itself by just probing with a voltmeter.

[@musicstevecom]

Yes! A lot of times it a bad solder joint, by probing or moving components, is a good way to troubleshoot and also pushing in\Out the board also can find lose components and then look from the bottom of the board for cracked or holes in solder joints.

[@martyjewell5683]

This was the last of the Pioneer 15wpc receivers. Pity they didn't keep this wattage in their line. I had an SX-434 purchased in 1975 for $127 but traded up in 1978 to an SX-650. I had purchased two cassette decks and wanted to edit tapes and the SX-650 had two tape monitors. The 50 series was better spec wise than the 30's. I thought the vented metal top on the 450 made more sense than the solid top SX-434. Did miss the PIONEER BLUE dial lights of the 30 series. Nice touches on the SX-450? A mic input, almost no other company offered this on their bottom line units. An aux input in addition to the tape monitor, good FM front end and phono input, plus that classy new look. These receivers weren't for loud music thru big inefficient speakers in large rooms. More for use with efficient speakers like the Boston Acoustics A-40's, in rooms 3 meters x 3 meters. Funny, you can lift a new 500 watt surround receiver with one hand.They're all plastic. Try lifting an SX-450, (19 lbs.) you'll need TWO hands. A great receiver, good value and worth the price.

[@xraytonyb]

You almost can't believe how well these performed unless you hear one in person. They also go quite loud for 15 watts! If they had an adjustable bias and DC balance, they would be perfect, but they work really well as they are. Back then, low cost didn't necessarily mean cheap!

[@antraciet]

Many thanks for this great video ! I am waiting for my (broken) SX 450. MAybe it has the same faulty components as yours. I am not an electronic technician, but i am learning, just as a hobby.

[@ShawnHolman77]

Where can I get the tuning instruction print out's? Thanks for you time an effort here.

[@Danman4000]

Nice Work!

[@ate508]

Great job! Now I have more to study about. What model number of HP signal generator are you using? I have two SX-680's to restore and this will help with some of it. Please make more videos, they're great. Sincerely, Doug

[@Poppinwheeeeellllllieeeeez]

I have one of these in my dining room with a pair of Bose 301 II. Fresh capacitors in the speakers. Sounds wonderful. The unit finds stereo, but after it warms up you need to retune the station a smidge. Wondering if it would be a minor tweak or a whole alignment procedure?

[@bobdoritique7347]

Merci for this video.

[@MC-ph7gr]

Hi. Do you know where I can buy vintage hifi, such as sony lbt v902, sony mhc 551, etc, online in the US? THX

[@nycitalianess7825]

I asked the same question! I actually was hoping I could buy a Vintage Stereo from the Gentleman in this video. I think his work is wonderful and trustworthy. I'm waiting to hear back from him on that. But in the interim... today I found a place in Maryland (I forget the name) but you can look it up easy bcuz they specialize only in vintage stereo systems!! You can ask for Mike who does all of the repairs & sales. I spoke to him today and he was super knowledgeable and very friendly and informative! They ship out anywhere in the USA & worldwide. Best to you!

[@SylvainThuret]

Hi im trying to replace the bulbs. Grabbed some new ones but don't know how to replace them :(

[@TheWarped45]

I work on commercial power amps that fail for various reasons I see mj15024 mj15023 tip42 2sc5200 and a mess of others short out either kicking the breaker or blowing the main fuse usually a 8 or 10A slow blow. I hate the yamaha 2500 when distortion is present on side 2 sometimes a bias issue.

[@walkingrobin9965]

Great video

[@steventownsend4557]

i was a tech way back i know how to repair all that old equitment i wonder if i could be use full again troubleshoot to componemt level and all the easy repairs like tape monitor switch one side out ?

[@Conscious1967]

Hello sir! I have Pioneer sx 737 which makes notice from one channel what could be the problem

[@juanpablosoto7357]

This video is AWESOME !!!! THANKS !!

[@lesbrown331]

K

[@coreyfellows9420]

I got one but no lights .. No power to lifhts . hit it with a meter and no juice to the lights . Any idea?

[@coreyfellows9420]

Hey Tony , big fan. I have this amp and while attempting to upgrade to a l.e.d bulb kit I blew out the entire light system. Any pointers?

[@hugeelen]

Hello, I think he explained in the video what he did for it.

[@northlake732]

So in actuality could you do all that work in one hour, which is probably all you could put into a $200 unit that is 40 years old. You are obviously very good at what you do, but is it cost effective for a customer? In the computer world, one hour is all you can invest before throwing it out and getting a new one.

[@Chrissy4605]

I have a Pioneer VSX-D6O8 that doesn't pass any signal down to my subwoofer. Any help with that would help.

[@dommy1715]

Hi, I received a used Pionner sx450 from facebook marketplace, my main issue is that one set of the speaker terminals require some type of pressure in order for them to output sound, can anyone tell me what could potentially be the problem?,

[@dcganske]

I have the SX 450 and works and sounds really good. Only thing that i see wrong is the volume dial on it must be getting dirty because it makes some type of static sound to it. Is there a way to clean that?

[@gioscervelo]

Gon one of these. Its pooched. Cant find replacement transistors so it will be a big deal to fix it up.

[@DavidBerquist334]

I have sx 980 and sx750 receiver i also have sa8100 and 8500mark 2 it has 2 power transformers

[@DavidBerquist334]

I see many tape decks and cd players dont have a line fuse so i put one in i have many videos of me doing that check them out let me know what you think i put disclaimer in discription saying consult a authorized service center before doing

[@kennynvake4hve584]

A thermal camera sure would help at 36:00 in the video...they are nice but to me expensive.....

[@victorsalcedo8127]

great video. I just got a hold of one same model. F.M does not tune. Would you be so kind and direct to a source to acquire the print.....Thanks in advance....Victor

[@Milsolen]

What are those lifht called becaus i got an sx550 here with broken bulbs and i cant find out what light these are

[@anthonydc3714]

How did you replace the original wedge lamps with LEDs wedge lamps. Did you have to solder them? thanks

[@johnathaneve1097]

I would like to know what type of transistor you replaced around minute 51 to 54 the transistor I'm thinking you pointed at is C12 223 e66 a I could be wrong but It is right below a little circular light brown I'm thinking transistor I know nothing about any of this If you could help me out that would be great Where can I find them

[@Hefty54]

Why not use air to plow out the dust?

[@dougguthrey2329]

Great videos! I'm currently in the process of ordering from Mouser to recap an SX-450. Is there a reason not to replace the current ceramic caps with MLCC (Multi Layer Ceramic Capacitors)? Thanks for your informative videos. A little envious of your work station!

[@xraytonyb]

Ceramics usually don't drift. Also, if you change any of the ceramic caps in the tuner section, it could throw the tuner out of alignment. Sometimes it even throws off the dial accuracy, as the caps are sometimes selected specifically for that tuner. Just do the electrolytics.

[@dougguthrey2329]

Thanks for your input. I'm not mixing electrolytics with ceramics. I noticed however there are variations of ceramics.

[@victorsalcedo8127]

thank you for sharing..

[@javierpeixable]

Hi, very good video !! Thanks for sharing knowledge I need help!! To repair an AM / FM Tuner Universum Model T3296 that you can not hear the audio, I can not find the fault :( I've been searching for the online repair manual and I can not find anything.

[@geoepi321975]

Javier pp i will help you

[@charleslaine]

I had one of these when I was in high school and all through college. But it burned out decades ago. I don't even remember what I did with it. Probably just tossed it being an idiot.

[@DavidBerquist334]

I have a sx 980 i paid 600$ for it November 1980 close out sale it was 650$ originally i like it they dont make this good quality any more i work wear they collect ewaste i saw a sx 1980 come in i couldnt have it

[@florenciomendez5529]

Is it too difficult to replace the dial cord?

[@musicstevecom]

YES

[@jp040759]

I was hoping you could help me. I am repairing my 1970s HH Scott 380R receiver. Something failed and took out 5 transistors on one channel. I am thinking a capacitor must have shorted and over biased something and caused an avalanche of destruction. Can you or anyone else steer me to a website app or website for getting cross-referenced replacements for the Japanese transistors that were used in this receiver? Thank you.

[@xraytonyb]

No doubt that the receiver could use a re-cap, but that is only one possibility for the failure. Many times, the small pre-amp transistors will begin to leak. As they warm up, the leak goes almost to a short. That causes the transistor to throw off the bias to the transistor connected to it, which throws off the bias of the next and so on. Because the amp is a DC (direct-coupled) design, there are no capacitors to decouple one stage from another. When one transistor fails, most or all of the transistors down the line fail as well. The little transistors are easy to find replacements. The outputs are a bit harder to find. The 2sa798 dual-package low noise transistors are really hard to find. If you watch my SX750 video, you'll see where I got counterfeit 2sa798s that were wired backwards. Anyways, sounds like you need to order some transistors and caps! Good luck!

[@jp040759]

Thanx.

[@adamwolfram6126]

Ha! "I'm smelling some electrons over here."

[@saddle1940]

I wish I could afford a Flir camera. It'd make this type of electron loss more visible!

[@williamstaten8102]

this is some good stuff

[@michaelscottcutler3627]

Great, informative video. I'm a novice but want more knowledge. I just found an SX 550 in the trash and would appreciate a video on repairing this model. Its interior looks different than the 450. Will you have a video on the 550? Hope so. (Also found a SX 1050, but haven't touched it yet.) Thanks again.

[@xraytonyb]

The 450 and 550 are very similar circuits. Download a manual for the 550 and you should be OK.

[@jasonthejawman5442]

The video's Rock

[@pattybuie5878]

where did you get the big blue tool holder

[@Chrissy4605]

I have a can of DeOxit 5!

[@elmersalinasovando1234]

Yo tengo un fisher lo malo q hoy dia ya no hay buenas estaciones ak en mexico pura porqueria pasan ya no hay aquellos programas q asta daban gusto oir se akabo lo bueno

[@davidvigil7720]

I own this very receiver, and needs some repair work, can you help me out?

[@xraytonyb]

Currently, I am not taking on any more jobs. I may start to do some repairs for others in the winter when things slow down a bit. If you are doing your own repairs, I would be happy to answer any questions you may have. Thanks for the comment!

[@davidvigil7720]

+xraytonyb I would love to do my own repair, but unfortunately I have limited access to the proper tools,,,, when you do start doing repairs again, I would like you to take a look.

[@justinsachs7270]

Great video. What would you suggest for someone that wants to start getting into this kind of stuff? I have no electrical engineering background, but I want to start taking apart receivers and figuring out how to fix them. Any good resources for understanding the foundations for this kind of work?

[@davedillard1]

I have a SX-450 was a Great stereo until someone pressed the Tape button with no Tape Deck hooked up! I was told it has a Channel blown out, so DONT press the TAPE DECK BUTTON WITHOUT A DECK HOOKED UP.

[@65Superhawk]

Hmmm. This seems unlikely to hurt anything. Maybe a coincidence?

[@davedillard1]

@@65Superhawk I think the owners manuel said not to?

[@65Superhawk]

@@davedillard1 very interesting! I will check the schematic and see why that would be. Thanks for the tip

[@davedillard1]

@@65Superhawk do you happen to repair them?

[@Lutzki140]

Super Corona Dope ;-)

[@int53185]

What was the power output of the amp?

[@xraytonyb]

15 watts per channel

[@Electrolab28Ag]

Where do you get your schematic from?

[@xraytonyb]

Lots of online sources for them. I think I got this one from HIFIENGINE.com. You need to get an account to be able to download schematics.

[@Electrolab28Ag]

Thanks. Great Videos by the way.

[@studamanduncan9728]

Get some fresh air man

[@johncano8745]

Call

[@MrTommy4000]

I got deez speakers taking all they give. whatfore deez swell up and make a big mess. wires cross and need to be spliced right ya know? i can only see what deez can role with till the extra man come up and says he gonna swap with the power amps from ac to dc, now ize jusy waking up from dreaming about 500rms per channel and he says its gonna happen right now ya see? you all heard of mach 3's from old radio shack? they come with 15's and a whole lot a deez. i recommend not for the beginner.