How to fix Sansui AU-7700 Integrated solid state stereo amplifier channel pops Output problem

Do you have random pops in your vintage stereo amplifier. Is it bad enough, that you fear damage to your speaker system? Well, more than likely the issue is due to a worn out speaker protect relay. When the contacts do not mate properly, the amp looses the speaker load, then when it makes connection again, the current surges resulting in a giant pop! Very irritating and over time could damage your speakers. Here is a possible solution! There could be other issues. Take it for whats its worth. If you do not feel comfortable doing this type work, take it to a reliable shop.

[@peterjmcgee4680]

I especially like the fact that you work on mostly vintage gear which is one of my hobbies

[@sean-ci3tv]

I have had that relay spacing issue and I took the old relay and pulled the bottom o.f it and soldered it to new one,always great when you upload a new video

[@nolimit7]

good video now I know what to look out for when diagnosing common issues.

[@bobblum5973]

Nice fix there, Terry! You make me want to dig out my old Sansui AU-555A amp and fix the one channel that went out years ago. As I recall I won't need to worry about the protect relay; it doesn't have one! It had always been a beautiful sounding amp, and I appreciated it having Bass, Midrange and Treble controls. Paired up with a Lafayette LT-D10 Dolby FM tuner, it sounded great as my main system in the late '70s / early '80s.

[@bobblum5973]

@Redrooster Thanks for the encouragement! I agree it was certainly a quality sounding amp. I've still got it and the LT-D10 tuner. The amp was given to me by one of my instructors at a tech college where I studied electronics. The channel was out then; I fixed it but it went out again while my brother was "borrowing" it. I think I found the schematic and service manual online some time ago, and confirmed I can still get the correct power transistors for the output stage. I just need to set aside the time and do it!

[@wedoshotz6645]

Wow, I never get easy repairs like that......lol. Good improv on the relay.

[@wizardx4187]

glad my 2x sansui au3900s from the orig owners (brothers who purchased in 1977~) are happy again

[@Techrewinds]

Super nice setup loving it keep up the good work!😍

[@jmcgatkinson]

I did find on one of the earlier Sansui Amplifier models 'noisy' small signal transistors around the tone controls; treble, bass, etc. It had IC's which were 'difference amplifiers' for low noise. You could detect the fault by using the Rx1kohm across c-e junction, and watch the needle 'bounce around'..

[@electrolytics]

Solid State wackiness is more like it. Thanks for the videos.

[@larrydering1598]

Excellent repair. I like the relay mod, nice work.

[@williamcarboni2614]

I love it, Terry you should be an actor love the comedy touch. Thanks

[@marcosribeiro1252]

Hello, how are you? I need the output transistors and the Sansuo G5700 icitators. Would you have it for sale or would you know of any contacts? Here in Brazil I can't find them. I also need those two plates that come out of the price plate, and go to the dicipator, where the output transistors go. If you can please help me..

[@amedeunuabona]

I have no right output from my Sansui au2022, regardless of the the input. Does anyone know what the problem could be???

[@danlampton]

It was good to see you with a nice Chardonnay.

[@chillidogkev]

I love solder wick and use it but I disagree that it protects your solder tracks unless you are very careful and don't have too many bites of the cherry when using it. Iron temp is critical versus number of hits needed to remove all the solder. All that said, it really has its place on the bench.

[@johnsimms3957]

I have a Pioneer receiver that does the exact same thing. Good video!

[@stevesus3295]

Sansui had this bad habit of using the bolts that hold the transistors to the heat-sink as the collector conductors through the PCB . Then over the years, the thickness of the PCB would shrink and corrosion would build up around the head of the bolts. They got to be taken out and cleaned up.

[@christurner1226]

Awesome channel, I was wondering if you could point me in the right direction, I need a bass potentiometer for a Technics SU V16 amp. Thanks

[@davidlindsey3007]

GReat video... huge help! Thanks

[@rciancia]

That was one awesome video Terry..... I'd say Marcia does not get enough of screen credit LOL..... Good fix to a common problem.. I did the same with my Marantz a few years back except I disassembled it and cleaned it. The contacts were all fouled.... :)

[@deadmusik9969]

I have a JVC AK300 where the right channel intermittently going in and out, any ideas? It will self correct if i turn the volume up or in a couple hours it will turn on the right channel, not even the VU meter shows any output, is it in my pre amp section? Thank you

[@killerta87]

I need to find someone to figure out my sansui 7070 receiver. Powers up, tuner is powered, there power into amp 2624 board but absolutely no output😔

[@mikesmuseum]

My 7700 is still working like a champ. I've babied it for over 25 years, I was lucky to find one. I'm impressed how easy that heatsink and board slid out of there. What is the part number of the relay that you had on hand? What a wonderful amp - one of my favorites! Well done Terry!

[@liquidatodovenegas9491]

Hello, thanks for the video. I have tha same problem, but i clean the relay and problem persist. The only difference is that this pops only appear when I active the tone control. If the tone control is not activated the pops sound not appear. Any suggestion? Thanks

[@dengsiao]

Hi Terry, i am searching for a service manual for a Vox Conqueror solid state amp (50 Watt) from the 1960's. The amp is dead. i got the circuit diagram but a service manual would be great for additional information.

[@Nirky]

Solid, D-Lab, very solid.

[@Asian_Connection]

You look like a master. Can you just me in the right direction? I have a Mark Levinson no.27 amp. When I turn it on I heard a strong pop on the right speaker and then the unit went into protection mode. Even time I turn it on the power switch would pop back to off with only pwr cable plugged in. The power light still lights, fuse is good. Any guidance from anyone would be greatly appreciated.

[@EngineeringVignettes]

Now that's class... D... lab. Cheers,

[@dal160]

Hi, just wondering if you can help please - I have a Arcam Alpha 10 that is going into protection mode (Red flashing light) not all the time though - sometimes i can power it up and play music for a good few hours with no problem then other times it will go into protection mode after 15mins, 30mins no exact timing to it - any help would be massively appreciated. Thanks

[@donmoore7785]

A replacement for the original relay with the correct spacing is in fact available.

[@sam127001]

right, but as he noted, not at your neighborhood electronics store.

[@robinsattahip2376]

Pregnant caps, cute, never heard it put that way before.

[@fardaz9116]

hi i have problem on my sansui au20000, that it has strange sound like wiizzz on woofer , when turn sound up, no difference for this strange sound, and it is in One channel. It is possible for you to tell me , where i can find the problem??

[@tubeDude48]

Terry...your one crazy dude! :) Have you done a video on your *audio* *test* *set* device?

[@sonnylou8087]

Bottoms up⚡️🍸.

[@zack4president]

I just inherited my father's old Sansui 9090 (Late 70's). It needs some TLC if you want to do a video on one of those. The left channel is very weak and it pops quite a bit. Not looking for free work, just found your channel and thought you might be interested.

[@jeremiahlyleseditor437]

You're a funny man. Great Job.

[@tigerbalm666]

Amazing!

[@russredfern167]

No crackles just blinking protector light. Changed out a few open resistors. This is for 9090db.

[@TroyPosey]

Blackstar, huh?... Never had their wine, but they make good guitar amps! 😏 Love my Blackstar S1-100 EL34B head & S1 412 Pro cab.

[@RobertKohut]

Nice!!

[@cabronesse386]

LOL... Great work!

[@westelaudio943]

I have had a channel popping but there wasn't even a protection relay. An intermittent AC128 was the cause.

[@jmcgatkinson]

It was getting to the point of the 'tin whisker' phenomenon. Germanium transistors (the earlier PNP types in the AC and AF prefixes) were noted for firstly being 'noisy', then shorting internally. Many AF 117 transistors in the RF stages of radios have been replaced...

[@preiter20]

Your feed mechanism needs a bias adjustment.

[@d-labelectronics]

That was Marcia at the helm

[@preiter20]

D-lab Electronics then everything was perfect! 😉.

[@donaldheitger6731]

Your a very lucky man to have such a nice wife

[@hestheMaster]

I need a white lab coat👨🏻‍⚕️🍷🍷🍷

[@hectorraigosa7149]

I have a sansui A 909 that stopped working after I pulled it out of storage. Everything fires up except no sound now.. with speakers disconnected.. meter lights do bounce slightly.. worked for about 5 minutes and then done with... I've read some feed back posts as it being basically low end or not worth repairing. Nut I disagree.. this unit is heavy and putting 80 watts per channel and very crip.. I had a 9090 years ago.. sound isn't much of difference.. speaker pairing has a ton to do with it.. A 909 or A 910 are under the radar sansui amps... people I noticed go after appearance rather than sound quality.. I started to search for replacement and was astounded asking prices for sansui. Marantz etc unit's.. so I decided to just have mine repaired as only fools pay extortion money.. sansui 9090 in my book in mint isn't worth anything above 400.. it's not a low production classic vehicle.. end of the story.. I found a 9090 to keep as back up for 260 in perfect working condition but needing a good cleaning..

[@8xlaxx]

Awesome gesture!...BUT... a thumbs down,...thought Terry was red wine guy? : )

[@bmh67wa]

So pouring a small amount of wine into the hole of the old relay cover wouldn't have served the same purpose as replacing it with a new relay? Now you tell me. I could have used that wine to lubricate a tube socket. Such a waste of good wine! You live and you learn I guess. 73

[@hadebui]

this sansui amp is not bad but the 7900 series was much better great sound and dynamic scene

[@daveogarf]

AHHHHHH! "Clippity-Doo-Dahh"

[@peterjmcgee4680]

Love your broadcast but sometimes you're a little dippy LOL been watching you for years

[@embreesmith7613]

Hhmmmmm White wine today !

[@kd5ozy]

I hear a little wine in the audio