Servicing a Friend's Pioneer SX-1250: Part 2

[@xraytonyb]

0:00 Tony's two cents 5:46 Power amplifier board service 6:55 Transistor leggings 12:52 Underrated relay issue 21:31 Power amp board is finished 22:31 Testing & adjusting the power amp board 31:15 Servicing & testing the equalizer amplifier (Phono Stage) 36:14 Testing the phono stage with the 3-30-300 test 41:26 A first look at the tuner section

[@NICK-uy3nl]

Have you given much thought about replacing contact relays with reed relays on the output path of the audio amp? reed relays have much higher current switching capacity and contacts don't suffer from oxidation and burn-outs because they operate in a vacuum - reed relays are also physically much smaller than contact relays.

[@xraytonyb]

Please note that my opening comments were NOT directed to anyone, but that I want to let everybody know that it is never my intention to offend or insult anyone.... especially those who come to this channel to offer their knowledge and experience and those who are just starting out in this hobby. I can't always answer every comment, but I do try to read them all. Thanks for watching!

[@mymessylab]

I’m writing this comment just after your intro. I couldn’t resist to tell you that I fully agree with all and each single word you’ve just said. Who love this hobby likes to share and learn everyday more. Your channel is one of the most educational I follow been always in the educated and gentle perimeters. Just keep like that. 👍

[@excentor]

Tony... you're a master and teacher for a lot of us, dont waste time explaining your intentions, we all know your intentions and we love your content and your person!!!!!!!! thank you so much for everything

[@nelsondog100]

I wish we lived in a different reality where they were more people like you possibly even leaders. Thanks for being you🙂

[@tommybewick]

Tony, I think you do need to say these things. We shouldn't be fighting with each other over anything about electronics. It's a hobby, It's fun, but that's all it is! Good for you to put out this video ! To quote Billy Preston, later used by Stephen Stills in his song; "Love the one you're with!"

[@WECB640]

Tony, your channel is fantastic and has given me great joy over the years. Keep up the GREAT work! 73 Bro.

[@thierrymallet1991]

bonjour de Paris en France...pour moi tu est un maitre en matière d'électronique!!! sur cette planète, il y en a toujours qui se chamaille ! c'est comme çà! tu fais un excellent travail!!!...pour moi! merci de tes vidéo ...je dois remettre en état mon SX1250 et vais suivre tes conseils et commander les pièces pour le miens !! Merci pour tout! Thierry.

[@Patrick-ke5qt]

I wish my biggest concern in this world was transistor corrosion 🤔

[@Homer19521]

You exemplify civility. Hope it rubs off on all of us.

[@jaybats7865]

You’re a good man “Charlie Brown”. It’s too bad that some people just can’t be happy no matter what the situation is and are argumentative about everything. All we can do is concentrate on good intentions and move on. Thanks for the fun that we share here. 😀

[@martyh9309]

Bravo on your "2 cents"!!!!

[@Spaceman-jo5mz]

Great channel Tony. Always peaceful, informative and good fun👍

[@alanvandusen76]

Well said opening and thank you for taking the time to address it. I can’t speak for everyone but imagine a overwhelming majority are here for the entertainment value and to occasionally gain some of your vast knowledge without the drama and hype that everyone is bombarded with on a daily basis. Personally I just like watching the repair and restoration of the equipment I like to work on and restore and get a different perspective on some of the same challenges and truly appreciate all the hard work you put into your content.

[@anandadesilva6558]

Tony, I came across your channel recently after it was honorably mentioned by Manual in his Electronics Old and New channel and I must say I am very glad I did. Like I told him also, you guys are repairing stuff I used to dabble in when I was 20+. Please keep it up. I am sure there are so many people who enjoy like I do and also learn from what you present. As for the black coating on the transistor leads, you are 100% correct. There was a time they were made like that. Probably to prevent oxidation. Those "top hat" type of transistors you just showed, were used in a lot of amps that were made in the '70s in the UK that I am familiar with. I am sure you know Clive Sinclair and his "cheap" stuff. Those were full of these transistors and very often the top used to fall off! Even though they had the gold plated leads, the failure was by the top falling off. There were also some metal can transistors like the 2N 2222s that had the legs made of "steel" like material. Along with the can, the leads would develop corrosion that looks like "tiny things growing" on them! If you scrape it, the material did not look like copper. Just some of the stuff I have come across. Thanks for what you do and the knowledge you are imparting!

[@nabun00bs]

I don't read or write comments on your channel often since your content is so good I watch it on a real TV. But yeah can't we all just get along? There are plenty of spaces on the internet to be a "sad ham". This ain't one of them! Thanks for all you do Mr. B!

[@apollorobb]

Those old TO-106 case transistors sure bring back memories I had a bunch of those as a kid my dad brought home from work he was a engineer for Honeywell back in the late 70's and 80's Those transistors got me my start in electronics Now what you do for a hobby i do for a living. Sansui had their relay game on with the G-22000 and 33000 amplifier they used huge ice cube relays in them .

[@mikepxg6406]

Good video and intro. Some people do get upset about trivial things. Well said. Keep up the fantastic work I look forward to your videos. Thank you Tony. Mike.

[@josephlalock8378]

👍 on the tony rant! well said and thank you for what you do.

[@EdwardLehman]

This is all for learning, from Tony or one of the viewers, that moves all of us to a higher place. We all can enjoy these great videos and just learn new and great things. Can't wait till I can start fixing my own stuff.

[@philipslighting8240]

Cant beleive someone would get upset about transistor Leads. !!

[@barryf5479]

I stopped getting on to Reddit for this same reason. Life's too short to get worked out about trivia. Keep up the good work.

[@stevent3450]

I agree with everything you said today :)Good Job !

[@isoguy.]

So true, People stand on their parapet shouting how right they are and will defend their stance to the last person standing without listening to reason are just afraid of losing their self perceived importance. (fingers in ears, shouting la, la, la) Back to the 60s please. Make love, not war.

[@petertimp5416]

Love your channel….thank you.

[@alexw890]

Tony, as someone who is new to this, your long form videos are incredibly helpful! From a fellow audio enthusiast and an XRAY tech: thank you so much for taking the time to make these. I got my bench set up yesterday and I’m about to take the plunge on my first amp, a Sansui AU-101!

[@keithtrauner1738]

Hear! Hear! life is too short for petty nonsense. Perfectly okay to hear that once in a while. Kind regards..K

[@jdmccorful]

Good session, learned lots;3,30 ,300mv. Will try it. Thanks again.

[@juliohormilla3862]

I totally agree with you on watching the news, that's why I prefer to watch channels like yours Tony. Thank you.

[@Uuuuuuurrgggggghhhhh]

I love your videos Tony. Just ignore the "haters".

[@sguttag]

Hey...relay guy here (again). The spec sheets are definitely, seemingly, contradictory. On the Omron MY4, they list it as 0.8A as the rated inductive "load." That is what drew my attention. And you are correct, the UR rating is 3A (AC or DC), per contact. They also state that its "switching" max is 176VA...which should be safe for the receiver...particularly since the contacts are doubled up. The Omron LY2 you showed does offer a significant current capability 7.5A on an inductive load (compared to 0.8A) and the UL rating is up to 10A. In the same package style as the LY2, the P&B (TE) K10 series can get you up to a 15A in that same package (K10P-11D15-24). I think the trade off when moving to the higher current contacts is that the contact formulation is different to handle that higher current. As such, it also will have a minimum current rating, in the case of the K10 series, 300mA @12V. So, the trade-off is do you want to protect for a worst case on high-output or better one's odds of handling lower-power situations? As most audio people know, the RMS output, particularly in a home setting is in the 1-watt or less with brief instances in the 5-10 watt range (of course, depending on the speaker sensitivity, room and individual listening preferences). So, when choosing the relay, do you go with ones that will handle the bulk of the use or perpetually concern oneself with the worst-case? It isn't like the relay you used will burst into flames when running the amp at rated output...it WILL carry it...just not forever. And, the breakdown of that relay showed that it did suffer, over time...a long time. I've seen various designs on higher powered amplifiers, including having large electrolytics in-line to block DC in addition to the monitoring circuits that will shut down the output if things go wrong. Great videos and I love seeing how you work through the problems and the cleaning. Can't wait to see you troubleshoot the Tuner section.

[@andybonneau9209]

Nice intro. Right on!

[@bretthibbs6083]

I've watched a lot of tech youtubers the repair electronics tony and I have to say that out of all of them you. 12voltvids, dlab electronics are the best in what you guys do and I'm not that much younger than you guys I'm 49 and I enjoy watching you guys videos a lot as myself I have audio equipment that's approaching 30 plus years now and I haven't used it much but I have it set up anyways due to the fact that my main system outside of the speaker were gifts from my mother who sadly passed away back in 2013. once in awhile I will go and open the stereo receiver up to make sure the caps haven't gone physically leaky but the last time I used it it sounded great.

[@jamesclawson9156]

Bravo

[@knifeswitch5973]

Thankyou Tony!

[@radio-ged4626]

The protection circuit is relay interesting. Great info on the current switching capabilities of the relays. I guess if they have been fitted from new and are only now being replaced the underrated relays are probably good enough for the amp.

[@solidstate90]

Love the intro Tony, So very True

[@t1d100]

Thank you, so much, for all that you do for us!

[@honestaquarian]

WELL SAID AT THE BEGINNING!!🎉Like Rodney King once said “Can’t we all just get along?”Oh and yes Copper tarnishes green color.

[@sirsuse]

I love tuner troubleshooting videos. Thank you Tony. ❤️

[@CulichorHimself]

When you know, you know!

[@kenmohler4081]

It is my understanding that gold does not tarnish. Almost by definition. That does not mean that everything that looks like gold is gold.

[@leaveempty5320]

Thanks for the videos. Love this old tech and how surprising good it is.

[@EdKy101]

3:33 People can be so nasty to each other for the smallest of reasons. I've personally left audiophile groups because of the nastiness and massive egos. This hobby and the music that goes with it is supposed to be RELIEF from the day to day and the stress it brings. My 2¢

[@jedi-mic]

I don't understand why somebody should be angry and hate just because of components, is more about them they're not happy in their mind. Disagreement is fine but you don't need to be hateful or critical you need to find your happy place What about using a diode network and transistor instead of the relay? I've got that on my speakers to protect the tweeter from DC why don't they use that type of network instead? Wouldn't it be better to replace the filter capacitors each one with 3 or 4 individual lower values giving you the same value as the original each

[@dhpbear2]

24:04 - I just have to laugh at the labeling on those input jacks, "POWER IN". I can imagine someone asking "is this used in case AC isn't available?" :)

[@marcodoria]

We all make mistakes. We (at least I think so) learn from them. If not so, then we're not learning anything! I learn as much from my mistakes as I do from other people's mistakes. It makes me think! So, please Tony, let other talk! It's an opinion, and as such, everyone is entitled to have one (even if it's wrong 🤣) thank you very much! Keep them coming! As always, and learning from you I wish peace, joy and all that's good for everyone! Cheers!

[@nabman_]

Someone got upset over tarnish or paint? Really??? Tony has enough experience to tell one from the other. Anyway, it's not that difficult to distinguish between them. Paint is shinier and it's square and even around the leg where it stops. Tarnish kind of fades out or shows pitting.

[@davidgriffin79]

29:54 10V/Div; 4 graticules to top of grid, Vp = 40V, Vrms=√(2)/2*Vp = 28.28V, Z = 8Ω, P = Vrms^2/Z = 100W.

[@dhpbear2]

9:45 - If it's dull (matte), it's tarnish.

[@fernarias]

The black leads are black lacquer used as an insulator just as clear lacquer is still used today for insulating copper wire still today. They used black so that, during installation, you could see where the lacquer stopped and bare leads started for soldering.

[@TheTarrMan]

I see your using the discontinued Fluke 187. Would a Fluke 87V MAX work for this job? I was doing research and just bought one with the combo kit and everything. I hope I picked the right one because this was supposed to be a "buy once, cry one" type purchase.

[@robertwoodruff6608]

Hello. This is a great video. I have a question with a problem I have for my freinds 1250. I was sent here from a Facebook post for help where someone claimed you had a video about constructing or replacing the Bias Diode on the 1250? I noticed the one in your video here has a different number on it than the one I have here that’s 72A. I opened to dust out the one for my friend and the condition of the lead on one was ready to go and broke off flush from just spray can air and I am now looking for a replacment or to rebuild it. The info these around has been hard to come by or over my head sadly.

[@g.fortin3228]

I really was waiting to see what the gain was on the new 992's for the phono boeard. I've had no luck getting higher gain FB they are always on the lower end of their bracket rating. Sourced from digikey and mouser too. If they are lower ( like 378 ) but still matched are we still ok ??

[@Katrina_L]

Hi,are you interested in trying a thermal camera to locate electrical faults and inspect energy efficiency?

[@jaghifi]

hey Tony, sorry for another question. I have a 1250 that ive repaced the filter caps, repopulated the stablizer board, and the bottom power supply board with new caps and silcon. Before all that there was a large inrush noise from the transformer when switched on. Now that problem still is there but its much less. transformer continues to buzz sligtly if you put your ear right up to it. is this normal and should i not be concerned. voltages are good.

[@josephlalock8378]

31:28 riddle me this: on the bottom of that board is a black capacitor which is obviously different from what is used in the other channel. bad pull during assembly i assume, yet you replaced that black one with a upw or upm but left the yellow low leakage in the other channel, in the same position. why not replace both with ukl so the channels are matchedf?

[@NovaluxStereophonic]

I have seen this occasionally on the SX-1250, those caps are actually part of the +/- regulated supplies for the phono and line sections. Not sure if this was "bad grabs" or maybe different parts were specified for the + and - rails??? In any case I have only seen the mismatch on about 20% of the units that I have worked on.

[@josephlalock8378]

@@NovaluxStereophonic do you leave them mismatched? i have yet to do a 1250.

[@xraytonyb]

You did it....you had to go and bring my attention to that! Now I'll have to go in there and replace them with like types, or it will trouble me for the rest of my days :) In all seriousness, thanks. Those yellow caps seem to not fail as the some of the other ones do, but I may go ahead and change it out just to match the other side. It seems to be just fine, however.

[@josephlalock8378]

@@xraytonyb there's a saying that you use about the wheel turning😁 thank you for replying, now i will be able to sleep knowing they will both be like parts.😝

[@NovaluxStereophonic]

@@josephlalock8378 I usually do full rebuilds on SX-1250s when they come in so I replace all of the electrolytics and tantalums on that board. Its a bit overkill, the majority of cap failures in the SX-1250 are in the stabilizer as xraytonyb covered. Cancel Reply

[@Gpray75]

@xraytonyb Hi I was looking for a refurb/restoration on my Sansui au717 and tee-jay sent me your way. I was hoping you'd be interested in helping me out! Thanks 🙏

[@xraytonyb]

Go over to Jordan Pier KZbin Channel. He does this for a living and is excellent. I spoke with him a while back and he said it's OK for me to refer people to him.

[@Gpray75]

@@xraytonyb Thank you sir 🙏