Sansui 9090 Part 3 - Final

In this final part to the series, we look at transistor matching and how to set up test equipment for tuner alignment. We also discuss the dB scaling system and what it means. This was a long project!

[@VinceRFelix-vw1pm]

Wow! What a video!! I learn alot from Tony's repair and restoration. Nothing wrong with long videos..... Please keep them coming. I just discovered Tony's videos and have alot of catching up to do. Thank you Tony for these wonderful repair videos.

[@floydloonie4880]

I wish my Sansui 9090 was in the same condition that one is now in!! Looks brand new and functions even better than when it was brand new 45 years ago. Maybe at some time in the future I'll get lucky and find a tech who has some of the same skills as Tony. But until then I'll continue to operate my receiver occasionally without any type of high volume sessions that might pop the aged components inside and kill it . I love my Sansui 9090, and consider myself fortunate to have had such a reliable stereo receiver for so many years! Thank you for sharing this video with the viewers!

[@chrygore]

You are a legend in MY mind and sincerely appreciate your wealth of knowledge and wisdom . ive learned so much about my own vintage stereos. I'm in isolation and I've swung back to this series because I've now watched most of the rest of your videos and because I own a 9090. These were amongst the first of your vids that I'd watched when I had stumbled upon you as a "tuber" - thanks again for all your videos Tony.

[@TY-ob7fz]

Thank you Tony. Thoroughly enjoyed this series and always enjoy as you probe thru the problems encountered. Your restoration is priceless and especially on a unit like this. I know the blue dial face, priceless !!! Again thank you to take the time to put this together and sharing with us.

[@JelckedeBoer]

I really enjoy your detailed videos. Without the details it is impossible to do this stuff correctly. An extra video on impedance matching would be appreciated. Thank!

[@Bill-Rocker]

I wanted to add my thanks. To take the time to help people you don't know takes a certain kind of human. The 1 2 3 parts were very useful even for a newb to minor repairs. I hope this stays on youtube for eternity.

[@tompas11A3n52KkX]

Another great video. You explain what you are doing in a good and easy way. Thanks for sharing!

[@wobboonstra9290]

It was a long video but definitely worth it. Again learned a lot. I like a dated explanation. thanks.

[@mkpleco]

This has been a great series. Thank you.

[@frankgeeraerts6243]

Really enjoyed this videos , you're a very inspiring teacher ................you remembered me i have a series 999 Sansui amp and tuner to repair waiting somewhere on the shelves for years Thanks.

[@bustersinclair]

i enjoy and learn from your vids mr tony. thank you for sharing your knowledge and wisdom.

[@kylesmithiii6150]

Thanks for the video. Congratulations! It is super well done and professional work!

[@barryg41]

Really enjoyed this series on the Sanusi. Good info on using the sg165. Thanks!

[@rdss2010]

Great work , congratulations

[@rodantkapoor9721]

I enjoyed your videos, you're a very good teacher!

[@patriotu.s.elections7879]

What a MASTER Tech You Are Indeed ! TY

[@apollorobb]

Thats why i use a Kenwood SG-5155 for alignment one of the best purchases i ever made

[@GeorgeEI7KO]

Excellent Tony

[@philipcraig5821]

Great video series on the 9090. I was recently given an 8080 for free. It's protect relay, front row number 3 blade and contact were melted away,.. 3/4 of the blade is gone. A fused resistor on the relay board failed short, taking a diode and 2SC944 out. There are also failed Zener diodes and other out of tolerance resistors as well on the same relay board. The power amp and PS boards along with the main OP transistors are all OK. I'm replacing all electrolytics, filter caps, plus fused and drifted resistors with metal film, generally restoring it like new to add to the collection. The curve tracer is a great tool, I have one my short list. Perhaps I'll look into building one from a kit like yours. Unlike the DCA 55, the Atlas DCA-75 Pro plugs into the USB port of any computer. The included Atlas software on memory stick is loaded, then it uses the DCA 75, and software along with with test results to display all the test information . You get curve plots, measurements, any failures and more. The DCA 75 together with my laptop allows me quickly and efficiently check and compare reference transistor specs in PDF files to the measured numbers and plots from each component under test. No, it doesn't test using the same level of current or voltage as a Curve Tracer does, the parts don't get hot or stressed. However, it does give the user plenty of useful info to match transistors quickly as well as diagnose other components, Thyristors, SCR's, Diodes, and more.. you can't hook it up wrong and toast the components under test! Well worth spending an extra 70$ more than the DCA-55. You also have a video on the Realistic STA-2000, I have one of them here I also got for free. I'll be restoring it once the 8080 is finished. Your channel rocks, I'm subscribed and 'like' the videos I watch. Thanks for taking time to making them for people like us who love vintage gear!

[@saarike]

Huh, what amount of information! Thanks, even though I didn't understand all. Thanks. There is a lot of things to learn in electronics. I have to be humble. :)

[@ElectoneGuy]

Just finished re-capping one of these for a friend. After adjusting the bias, when you try to put the fuses back in - major sparks (and yes, the power was off and it was unplugged). Residual capacitor charge on the fuse terminals? No damage, but scares the hell out of you.

[@raulsierra7414]

Very good video

[@sv7gbr]

Congratulations for your excellent work and everything you share. Now about the dB scaling system and the usual confusion between Japanese ''SG'' & American ''SG'', after searching the various internet converters-calculators I came to the conclusion that the Japanese ''SG'' values are in dbuV EMF, while the American ''SG'' values are in uV PD. This tell me that the Japanese ''SG'' values have to do with open circuit dbuV while the American ''SG'' with closed circuit uV, mV or V . Hope this helps.

[@kev-the-windsurfer.]

A great video!! From one Sansui expert to another!! I would like, if possible a little more detail on how you set up for the IF alignment, Sansui are the worst with their alignment instructions/methods, its Genescope or nothing from those guys!! I have been using my scope and sweep gen to look at the IF response, but when you did it, you kind of just peaked it out rather than looking at the IF response curve....It looked like a pretty good method to be honest. I am doing quite a few alignments these days, I am finding these old tuners are starting to drift somewhat, so really I am just interested to know a little more about how you set some of that up... I also have a Spectrum analyzer which I'm sweeping IF transformers with, which is another good way of doing it. I have a Sansui TU9900 on the bench at the moment, and that is certainly a complicated beast indeed, its been tampered with, alignment is way way off.....So anyways, I hope you may be able to find some time to do some more instructions on FM alignments, I really enjoy your approach, I have most of the gear you have, so I'm always interested in how you're setting some of these alignments up, especially with those Kooky Sansui alignment instructions. Thanks Tony and all the best!!

[@lawrencelivingston8869]

Incredible thorough Great work

[@RobertKohut]

Nice!! Thanks!

[@ronaldkastner5186]

I enjoyed all the videos. I have an 8080 and my function selector will not line up properly in order to play FM. I can hold it in between functions to get it to play however when I let go it falls into place and of course I lose the FM. I was wondering if you give me your recommendation as to how I can remedy my issue. Thanks Ron

[@suzakule]

This line of amp ( I have a 9090) has a horrid history of problems with the switches ( roatory ) and the potentiometers, I'm having major problems with mine, though I only scanned through your vid for now, I really did not notice if this problem was addressed.

[@JelckedeBoer]

I managed to fix my 8080 with your instructions! The hfe of the MJE2955T is 228 and the hfe of the MJE3055T is only 75 , should these be better matched?

[@Mr_Meowingtons]

i found a B&K transistor beta tester that would work fine for matching transistors?

[@pdppanelman5889]

Nice Video, Nice Receiver, Nice Guy - what more could you want?

[@plcamp1]

Have you ever implemented FET speaker disconnects to replace speaker relays? On amps with B+ and B- above 30Vdc...relays cannot break such a fault without arcing...but FETs can handle that protection, and perform it vastly faster with no arcing risk. The relay attempting to short speakers to ground is an attempt to protect speakers even if an arc destroys the relay...but I would think it vastly better solution to get rid of relays entirely in this application?

[@xraytonyb]

I remember seeing circuits that used similar technology to switch the power rails off very rapidly, rather than breaking the speaker output line through a relay. It does work much faster and effectively than a relay, but if the FET (or solid state switching device) shorts, there is no protection. The advantage would be that if something shorts, the power would be cut to the transistors and the rest of the circuit, hopefully reducing the amount of components that fail. The relay method only protects the speakers, but with the power still stays applied to the circuit. This is why a shorted transistor can take out additional circuitry when using the traditional relay protect circuit. Maybe this would be an interesting subject to experiment with someday ;)

[@roberto9666]

Tony, many thanks. I acquired a 771 back in 1975, and now have a bit of a collection of 7070s and 8080s going. My 9090 arrived yesterday and unfortunately got smashed in transit. You mentioned a new faceplate glass - where did you get that?

[@xraytonyb]

The owner purchased it somewhere. I'm not sure where, but I suspect he found it on eBay. I know some people are still making them for select models of receivers.

[@roberto9666]

xraytonyb thank you. I’ll attempt to have one made here in Melbourne Australia.

[@TheChipMcDonald]

I grew up listening to one of these as a child, and I can no longer afford a used one. There must be something to the nature of the transformer + output transistors - what is the closest to this new? The bass even in the video seems... Incredibly warm as I remember, it's got to be some resonance aspect of the transformer... Ahrgh

[@stefandegraaff1817]

Hi, i like your video's and really learned some things here. One thing i would like to see wich i haven't yet is how do you clean things? Like the pcb's or cabinets of the recievers. Thanks allot

[@jovanj.9400]

Hi, I have 8080 model and im just wondering should I adjust VU meters pots? It seems to me when I am on low volume below 10% meters needels are barely moving, if I turn volume upper they move, but im not sure if the readung is good, so some tip would be helpful. By the way great work on this reciever.

[@floydloonie4880]

@ Jovan J.- In my opinion the meters sound like they are functioning fine... Unless you have the necessary test equipment and actually have been properly trained, so that you know what you are doing, ( Watching a video online is NOT "training") most likely you will do nothing but screw up a wonderful looking and sounding unit!. Do you really need to know exactly how much power is being produced? I doubt it!! I have a 9090, and I have almost never concentrated on the meters for exact wattage being used. If you break a meter you will not easily or cheaply find a replacement for it so why mess around?? What is the purpose?? The meters will barely move at low volume because almost no power is being used until the knob is turned past half way up. But it's your receiver, so go for it!!

[@jovanj.9400]

@@floydloonie4880 Thanks for the reply, I still have this unit working and didnt mess around with meters. I post this question year ago because then i got this unit and didnt know mutch about it, especialy meters i tought they should move the needels like analog meters on cassete decks, but now i realized there is a diference, this reciever has POWER merers which measure power in watts and it is fine if they not move on low volume, decks have VU meters and measure signal streinght in decibels and they move on lower volume...so that is all about my question before because i didnt have amp with power meters before. Anyway i still have it and works great, I had problems with left channel was droping i couldnt resolve so i clean controls, replace speakers relay with new one, resolder some joints till i finali found bad solder conecton on one small signal wire, basicly wire copper was bearly touching a solder connection, factory fault...now it works like a charm, even with two pairs of speakers, (Sony SS G3 and JBL LX55) On 4 ohm load, seams it never goes tired. If you have 9090 it is even better, top of the line along with 9090db, analog recievers and amps are great from that era, much better than new stuff in my opinion but they require maintence.

[@wayneg296]

👍👍😎✌️🤟

[@SantanKGhey1234]

watched all your videos... where are you located? id love you to service my 9090 and G7500!!

[@jrockofages5413]

Did Tony ever respond to you? I have a 9090 still going strong but would like it overhauled. Thank you

[@sweetybean1]

@@jrockofages5413 same here, i dont think he responds to any one

[@jrockofages5413]

I think you're right. I used to have a friend that did this...but he passed suddenly. Still looking for someone who has the passion and really "gets it".

[@sweetybean1]

@@jrockofages5413 yes. I dont get it. Wish I did though

[@SantanKGhey1234]

he did respond back withan email that he has scaled back not taking too much work due to wanting to spend more time with his family... i respect that... he is too far from me anyways

[@bryanm3532]

could i send you my 9090db to be recap

[@johnsweda2999]

Seems strange why they didn't put the heat sinks on the transistors directly! they just floating in the air..! can't see this is a good idea? The heat is only transmitted from the chassis of the amplifier not directly off the transistor, maybe some mica and copper shims on top of the transistors so it's making contact with the heat sink might be better. Anybody know why they've done it like that

[@xraytonyb]

It actually uses a two-piece heatsink. The inside half has the fins facing in towards the inside of the amp. The transistors attach to that half. The outside half attaches to the inside half with 12 screws. That said, I totally agree with you. It's not a very good design. These amps tend to run rather hot when playing at high volumes. I think a larger standard style heatsink would have been a better option.

[@johnsweda2999]

xraytonyb yes. I was thinking you can get these Circular heat sinks this might be better just to put them on individual power transistors, with no connection to the chassis, or any other transistor's. Or if you want to be really radical make a enclosed container with a partition down the centre for the transistors to bolt to attached to the outside of the chassis, feeding the wires out through rubber grommets and sealed in with silicone adhesive, and fill the container with oil this would have the best heat dispersion I would have thought. I've always thought this would be the best idea for the transformer in especially in amplifiers to be immersed in oil in its own container, this should cut down any acoustic vibrations caused by hum from a transformer being sent down the circuitry into the amplifier circuit do you have an opinion on this?

[@johnsweda2999]

There is royalty free music you can play. What would be nice is if you recorded it before a restoration/modification and record it after the restoration to here if there's any difference.

[@mannyblue265]

Hi tony I have a 9090 needed to be service .how do I contact you ,thanks

[@xraytonyb]

Please read the note at the beginning of all my videos ;)

[@JVerschueren]

Amazing how just thermal cycles over years of use can 'walk out' screws, isn't it, especially in aluminium. I know I'm late watching this, but, for future reference, get a stick of Loctite 248 to prevent that from happening again. Edit: 2SC984 transistors are getting a little bit rare? -they were unobtaneum when I was repairing these sets in the early 1990's, so, obviously, either knock-offs were produced since then or reserves were somehow unearthed... I'd guess the first explanation. Not saying the copies were/are bad, just not original. Edit of edit: so you just happened to have an original, eh? -that's cheating!!

[@lawrencelivingston8869]

I have the same amp Should send it to you

[@gregorymcgee100]

This amp was obviously built back when amplifiers and receivers were conservatively rated, and rated at 20-20,000Hz. None of this 1Khz.@10% T.H.D. crap to pad the specs.

[@almo8989]

I totally agree. Modern receivers are like 10 lbs and need those BS specs to trick noobies. I hate it when multi channel receivers will add up all the watts per channel to come up with this big number and they put it on the front as a sticker. 500 watts!

[@rajandransinnappan335]

think only two amps are the best ever vintage marantz and vintage kenwoods

[@kylemccourt663]

You must not be familiar with the SX 1250 and 1280 by Pioneer then. Notoriously the best receivers of the 70's and were copied by almost every manufacturer.

[@johnsenchakinternetnetwork2025]

STOP SENDING EXCESSIVELY LONG VIDEOS ENOUGH IS ENOUGH

[@1959Berre]

You don't have to yell. If you don't like what you see, STOP WATCHING.

[@TY-ob7fz]

John Senchak Internet Network Security John Senchak Internet Network Security You really don’t have to watch. What tony does is fine, and the experience he shares is invaluable. Beats staring at a blank wall any time !!

[@caroman6761]

I couldn't understand what you like? You don't need to watch them? Or you can do it like me, watch them im Parts, absolutely no problem in time of Internet. But: Never ask a high qualified KZbinr for short Videos. I'm so happy about the lot of work of xraytonyb. I could learn a lot in his vids, much more, than in the 10 or 20 Min vid of other youtubers.

[@johnsweda2999]

John Senchak Internet Network Security you need alphabetical spaghetti electronics

[@TheChipMcDonald]

Even for a troll that's idiotic.

[@rajandransinnappan335]

think only two amps are the best ever vintage marantz and vintage kenwoods